System and Method for Non-Blocking State Synchronization Between Services

A method, computer program product, and computer system for implementing a backend service for blocking free processing of physical entities events, including add, remove, update, query. Physical entities blocking delays may be delegated to maintenance tasks, which may run under a single thread with a scheduler and may merge successive pending events.

BACKGROUND

Consider an application that manages a set of logical objects corresponding to some physical entities with substantial response times such as network elements or hardware (HW) components. A non-limiting example of such application is an NVME/TCP auto discovery solution that maintains a set of NVMe/TCP ports, each one communicating with a centralized discovery controller through mDNS protocol in conjunction with a TCP/IP based kickstart protocol.

Such application could be split into several microservices. In the above example, it may make sense to split the network interaction including mDNS and kickstart messaging into a “backend” service. The client logic, namely the “frontend” service may control the backend service using some management commands, including at least, e.g., add, remove, update commands. Additionally, it may periodically query the object's state using a query command.

In order to implement the above management protocol, a standard RPC messaging system may be suitable. For simplicity, assume that the frontend service is the initiator of all commands, while the backend service is a responder only. Thus add, remove update are “push” commands, while query is a “pull” command. For each command, the backend service processes the command and replies when finished. The complication is that some commands may block for a substantial period of time so the RPC reply can be delayed. It may be possible to have the backend service queue the incoming commands and process them in background. This way RPC is non-blocking but the command processing is delayed. This is the case, for instance, with the remove command in the example. Notice that during the delete processing backend service may still reply queries regarding the object being deleted as if it still exists. Moreover, if subsequent add command arrives on the same object, backend service may refuse to add this port as the same port still exists and even may confuse the frontend service by adding the stale object info to query replies. Therefore, it may be beneficial to provide non-blocking RPC add, remove, update commands with the microservices maintaining a mutually consistent view of the objects.

BRIEF SUMMARY OF DISCLOSURE

Example embodiments of the present disclosure may include methods for implementing a backend service for managing a set of managed objects. The backend service may consist of a single “management task” that is responsible for processing client commands including at least, for example, add, update, remove, query commands, and a “maintenance task” per each management object. Each management object blocking processing (given its substantial delay times) may be delegated to its respective maintenance task. At times when some maintenance task is blocked, the respective managed object may be reported to the rest of the system as busy thus prohibiting the full use of that object. At all other times the respective managed object may be available for use to the rest of the system. Some backend service implementations may use (but are not limited to the use of) cooperative multitasking (i.e., async/await technology). This way thread allocated cost and locking overhead may be reduced. Note, however, that alternative concurrency technologies such as multithreading or multiprocessing may be used. Most backend service implementations do not require add, update, remove, query commands queuing. In effect, memory footprint is reduced.

In one example implementation, a method, performed by one or more computing devices, may include but is not limited to executing, by a computing device, a management task by a backend service, wherein the management task does not block on managed object response delays of a plurality of managed objects. A maintenance task may be executed per managed object of the plurality of managed objects by the backend service, wherein the maintenance task may be a background task that blocks on respective managed object delays.

One or more of the following example features may be included. All code of the backend service may run in a single thread that includes a scheduler. The management task may process user commands, wherein the user commands may include at least one of an add command, an update command, a remove command, and a query command. When the management task is one of the add command and the update command, one of: the update command may be overridden if an ID associated with a managed object of the plurality of managed objects exists in a data structure stored in a system memory, and a first flag may be unset in the data structure, an entry for the ID may be added in the data structure to be stored in the system memory if the ID associated with the managed object of the plurality of managed objects does not exist and starting a new maintenance task for the ID, and an event for the maintenance task corresponding to the ID may be triggered. When the management task is the remove command, one of: a first flag may be set and a second flag may be unset if an ID associated with a managed object of the plurality of managed objects exists in a data structure stored in a system memory and the first flag is unset, and an event for the maintenance task corresponding to the ID may be triggered. When the management task is the query command, one of: information of all the plurality of managed objects may be collected, and a status may be set for each respective managed object of the plurality of managed objects to active if the respective managed object is idle, and the status may be set for each respective managed object of the plurality of managed objects to inactive if the respective managed object is not idle. Information may be removed from a system memory based upon, at least in part, information in a data structure stored in a system memory. A connection may be torn down based upon, at least in part, information in the data structure stored in the system memory. A new connection may be brought up based upon, at least in part, information in the data structure stored in the system memory.

In another example implementation, a computing system may include one or more processors and one or more memories configured to perform operations that may include but are not limited to executing, by a computing device, a management task by a backend service, wherein the management task does not block on managed object response delays of a plurality of managed objects. A maintenance task may be executed per managed object of the plurality of managed objects by the backend service, wherein the maintenance task may be a background task that blocks on respective managed object delays.

One or more of the following example features may be included. All code of the backend service may run in a single thread that includes a scheduler. The management task may process user commands, wherein the user commands may include at least one of an add command, an update command, a remove command, and a query command. When the management task is one of the add command and the update command, one of: the update command may be overridden if an ID associated with a managed object of the plurality of managed objects exists in a data structure stored in a system memory, and a first flag may be unset in the data structure, an entry for the ID may be added in the data structure to be stored in the system memory if the ID associated with the managed object of the plurality of managed objects does not exist and starting a new maintenance task for the ID, and an event for the maintenance task corresponding to the ID may be triggered. When the management task is the remove command, one of: a first flag may be set and a second flag may be unset if an ID associated with a managed object of the plurality of managed objects exists in a data structure stored in a system memory and the first flag is unset, and an event for the maintenance task corresponding to the ID may be triggered. When the management task is the query command, one of: information of all the plurality of managed objects may be collected, and a status may be set for each respective managed object of the plurality of managed objects to active if the respective managed object is idle, and the status may be set for each respective managed object of the plurality of managed objects to inactive if the respective managed object is not idle. Information may be removed from a system memory based upon, at least in part, information in a data structure stored in a system memory. A connection may be torn down based upon, at least in part, information in the data structure stored in the system memory. A new connection may be brought up based upon, at least in part, information in the data structure stored in the system memory.

In another example implementation, a computer program product may reside on a computer readable storage medium having a plurality of instructions stored thereon which, when executed across one or more processors, may cause at least a portion of the one or more processors to perform operations that may include but are not limited to executing, by a computing device, a management task by a backend service, wherein the management task does not block on managed object response delays of a plurality of managed objects. A maintenance task may be executed per managed object of the plurality of managed objects by the backend service, wherein the maintenance task may be a background task that blocks on respective managed object.

One or more of the following example features may be included. All code of the backend service may run in a single thread that includes a scheduler. The management task may process user commands, wherein the user commands may include at least one of an add command, an update command, a remove command, and a query command. When the management task is one of the add command and the update command, one of: the update command may be overridden if an ID associated with a managed object of the plurality of managed objects exists in a data structure stored in a system memory, and a first flag may be unset in the data structure, an entry for the ID may be added in the data structure to be stored in the system memory if the ID associated with the managed object of the plurality of managed objects does not exist and starting a new maintenance task for the ID, and an event for the maintenance task corresponding to the ID may be triggered. When the management task is the remove command, one of: a first flag may be set and a second flag may be unset if an ID associated with a managed object of the plurality of managed objects exists in a data structure stored in a system memory and the first flag is unset, and an event for the maintenance task corresponding to the ID may be triggered. When the management task is the query command, one of: information of all the plurality of managed objects may be collected, and a status may be set for each respective managed object of the plurality of managed objects to active if the respective managed object is idle, and the status may be set for each respective managed object of the plurality of managed objects to inactive if the respective managed object is not idle. Information may be removed from a system memory based upon, at least in part, information in a data structure stored in a system memory. A connection may be torn down based upon, at least in part, information in the data structure stored in the system memory. A new connection may be brought up based upon, at least in part, information in the data structure stored in the system memory.

DETAILED DESCRIPTION

In some implementations, the present disclosure may be embodied as a method, system, or computer program product. Accordingly, in some implementations, the present disclosure may take the form of an entirely hardware implementation, an entirely software implementation (including firmware, resident software, micro-code, etc.) or an implementation combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, in some implementations, the present disclosure may take the form of a computer program product on a computer-usable storage medium having computer-usable program code embodied in the medium.

In some implementations, any suitable computer usable or computer readable medium (or media) may be utilized. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. The computer-usable, or computer-readable, storage medium (including a storage device associated with a computing device or client electronic device) may be, for example, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer-readable medium may include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a digital versatile disk (DVD), a static random access memory (SRAM), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, a media such as those supporting the internet or an intranet, or a magnetic storage device. Note that the computer-usable or computer-readable medium could even be a suitable medium upon which the program is stored, scanned, compiled, interpreted, or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory. In the context of the present disclosure, a computer-usable or computer-readable, storage medium may be any tangible medium that can contain or store a program for use by or in connection with the instruction execution system, apparatus, or device.

In some implementations, computer program code for carrying out operations of the present disclosure may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Java®, Smalltalk, C++ or the like. Java® and all Java-based trademarks and logos are trademarks or registered trademarks of Oracle and/or its affiliates. However, the computer program code for carrying out operations of the present disclosure may also be written in conventional procedural programming languages, such as the “C” programming language, PASCAL, or similar programming languages, as well as in scripting languages such as Javascript, PERL, or Python. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the internet using an Internet Service Provider). In some implementations, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGAs) or other hardware accelerators, micro-controller units (MCUs), or programmable logic arrays (PLAs) may execute the computer readable program instructions/code by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present disclosure.

In some implementations, the flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of apparatus (systems), methods and computer program products according to various implementations of the present disclosure. Each block in the flowchart and/or block diagrams, and combinations of blocks in the flowchart and/or block diagrams, may represent a module, segment, or portion of code, which comprises one or more executable computer program instructions for implementing the specified logical function(s)/act(s). These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the computer program instructions, which may execute via the processor of the computer or other programmable data processing apparatus, create the ability to implement one or more of the functions/acts specified in the flowchart and/or block diagram block or blocks or combinations thereof. It should be noted that, in some implementations, the functions noted in the block(s) may occur out of the order noted in the figures (or combined or omitted). For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved.

In some implementations, the computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed (not necessarily in a particular order) on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions/acts (not necessarily in a particular order) specified in the flowchart and/or block diagram block or blocks or combinations thereof.

Referring now to the example implementation ofFIG.1, there is shown a backend service process10(also referred to as backend service10) that may reside on and may be executed by a computer (e.g., computer12), which may be connected to a network (e.g., network14) (e.g., the internet or a local area network). Examples of computer12(and/or one or more of the client electronic devices noted below) may include, but are not limited to, a storage system (e.g., a Network Attached Storage (NAS) system, a Storage Area Network (SAN)), a personal computer(s), a laptop computer(s), mobile computing device(s), a server computer, a series of server computers, a mainframe computer(s), or a computing cloud(s). As is known in the art, a SAN may include one or more of the client electronic devices, including a Redundant Array of Inexpensive Disks/Redundant Array of Independent Disks (RAID) device and a NAS system. In some implementations, each of the aforementioned may be generally described as a computing device. In certain implementations, a computing device may be a physical or virtual device. In many implementations, a computing device may be any device capable of performing operations, such as a dedicated processor, a portion of a processor, a virtual processor, a portion of a virtual processor, portion of a virtual device, or a virtual device. In some implementations, a processor may be a physical processor or a virtual processor. In some implementations, a virtual processor may correspond to one or more parts of one or more physical processors. In some implementations, the instructions/logic may be distributed and executed across one or more processors, virtual or physical, to execute the instructions/logic. Computer12may execute an operating system, for example, but not limited to, Microsoft® Windows®; Mac® OS X®; Red Hat® Linux®, Windows® Mobile, Chrome OS, Blackberry OS, Fire OS, or a custom operating system. (Microsoft and Windows are registered trademarks of Microsoft Corporation in the United States, other countries or both; Mac and OS X are registered trademarks of Apple Inc. in the United States, other countries or both; Red Hat is a registered trademark of Red Hat Corporation in the United States, other countries or both; and Linux is a registered trademark of Linus Torvalds in the United States, other countries or both).

In some implementations, as will be discussed below in greater detail, a backend service, such as backend service10ofFIG.1, may execute, by a computing device, a management task by a backend service, wherein the management task does not block on managed object response delays of a plurality of managed objects. A maintenance task may be executed per managed object of the plurality of managed objects by the backend service, wherein the maintenance task may be a background task that blocks on respective managed object delays.

In some implementations, the instruction sets and subroutines of backend service10, as well as any of the data/information described throughout, which may be stored on storage device, such as storage device16, coupled to computer12, may be executed by one or more processors and one or more memory architectures included within computer12. In some implementations, storage device16may include but is not limited to: a hard disk drive; all forms of flash memory storage devices; a tape drive; an optical drive; a RAID array (or other array); a random access memory (RAM); a read-only memory (ROM); or combination thereof. In some implementations, storage device16may be organized as an extent, an extent pool, a RAID extent (e.g., an example 4D+1P R5, where the RAID extent may include, e.g., five storage device extents that may be allocated from, e.g., five different storage devices), a mapped RAID (e.g., a collection of RAID extents), or combination thereof.

In some implementations, network14may be connected to one or more secondary networks (e.g., network18), examples of which may include but are not limited to: a local area network; a wide area network or other telecommunications network facility; or an intranet, for example. The phrase “telecommunications network facility,” as used herein, may refer to a facility configured to transmit, and/or receive transmissions to/from one or more mobile client electronic devices (e.g., cellphones, etc.) as well as many others.

In some implementations, computer12may include a data store, such as a database (e.g., relational database, object-oriented database, triplestore database, etc.) and may be located within any suitable memory location, such as storage device16coupled to computer12. In some implementations, data, metadata, information, etc. described throughout the present disclosure may be stored in the data store, including the data structure noted below. In some implementations, computer12may utilize any known database management system such as, but not limited to, DB2, in order to provide multi-user access to one or more databases, such as the above noted relational database. In some implementations, the data store may also be a custom database, such as, for example, a flat file database or an XML database. In some implementations, any other form(s) of a data storage structure and/or organization may also be used. In some implementations, backend service10may be a component of the data store, a standalone application that interfaces with the above noted data store and/or an applet/application that is accessed via client applications22,24,26,28. In some implementations, the above noted data store may be, in whole or in part, distributed in a cloud computing topology. In this way, computer12and storage device16may refer to multiple devices, which may also be distributed throughout the network.

In some implementations, computer12may execute a storage management application (e.g., storage management application21), examples of which may include, but are not limited to, e.g., a storage system application, a cloud computing application, a data synchronization application, a data migration application, a garbage collection application, or other application that allows for the implementation and/or management of data in a clustered (or non-clustered) environment (or the like). In some implementations, backend service10and/or storage management application21may be accessed via one or more of client applications22,24,26,28. In some implementations, backend service10may be a standalone application, or may be an applet/application/script/extension that may interact with and/or be executed within storage management application21, a component of storage management application21, and/or one or more of client applications22,24,26,28. In some implementations, storage management application21may be a standalone application, or may be an applet/application/script/extension that may interact with and/or be executed within backend service10, a component of backend service10, and/or one or more of client applications22,24,26,28. In some implementations, one or more of client applications22,24,26,28may be a standalone application, or may be an applet/application/script/extension that may interact with and/or be executed within and/or be a component of backend service10and/or storage management application21. Examples of client applications22,24,26,28may include, but are not limited to, e.g., a storage system application, a cloud computing application, a data synchronization application, a data migration application, a garbage collection application, or other application that allows for the implementation and/or management of data in a clustered (or non-clustered) environment (or the like), a standard and/or mobile web browser, an email application (e.g., an email client application), a textual and/or a graphical user interface, a customized web browser, a plugin, an Application Programming Interface (API), or a custom application. The instruction sets and subroutines of client applications22,24,26,28, which may be stored on storage devices30,32,34,36, coupled to client electronic devices38,40,42,44, may be executed by one or more processors and one or more memory architectures incorporated into client electronic devices38,40,42,44.

In some implementations, one or more of storage devices30,32,34,36, may include but are not limited to: hard disk drives; flash drives, tape drives; optical drives; RAID arrays; random access memories (RAM); and read-only memories (ROM). Examples of client electronic devices38,40,42,44(and/or computer12) may include, but are not limited to, a personal computer (e.g., client electronic device38), a laptop computer (e.g., client electronic device40), a smart/data-enabled, cellular phone (e.g., client electronic device42), a notebook computer (e.g., client electronic device44), a tablet, a server, a television, a smart television, a smart speaker, an Internet of Things (IoT) device, a media (e.g., video, photo, etc.) capturing device, and a dedicated network device. Client electronic devices38,40,42,44may each execute an operating system, examples of which may include but are not limited to, Android™, Apple® iOS®, Mac® OS X®; Red Hat® Linux®, Windows® Mobile, Chrome OS, Blackberry OS, Fire OS, or a custom operating system.

In some implementations, one or more of client applications22,24,26,28may be configured to effectuate some or all of the functionality of backend service10(and vice versa). Accordingly, in some implementations, backend service10may be a purely server-side application, a purely client-side application, or a hybrid server-side/client-side application that is cooperatively executed by one or more of client applications22,24,26,28and/or backend service10.

In some implementations, one or more of client applications22,24,26,28may be configured to effectuate some or all of the functionality of storage management application21(and vice versa). Accordingly, in some implementations, storage management application21may be a purely server-side application, a purely client-side application, or a hybrid server-side/client-side application that is cooperatively executed by one or more of client applications22,24,26,28and/or storage management application21. As one or more of client applications22,24,26,28, backend service10, and storage management application21, taken singly or in any combination, may effectuate some or all of the same functionality, any description of effectuating such functionality via one or more of client applications22,24,26,28, backend service10, storage management application21, or combination thereof, and any described interaction(s) between one or more of client applications22,24,26,28, backend service10, storage management application21, or combination thereof to effectuate such functionality, should be taken as an example only and not to limit the scope of the disclosure.

In some implementations, one or more of users46,48,50,52may access computer12and backend service10(e.g., using one or more of client electronic devices38,40,42,44) directly through network14or through secondary network18. Further, computer12may be connected to network14through secondary network18, as illustrated with phantom link line54. backend service10may include one or more user interfaces, such as browsers and textual or graphical user interfaces, through which users46,48,50,52may access backend service10.

In some implementations, the various client electronic devices may be directly or indirectly coupled to network14(or network18). For example, client electronic device38is shown directly coupled to network14via a hardwired network connection. Further, client electronic device44is shown directly coupled to network18via a hardwired network connection. Client electronic device40is shown wirelessly coupled to network14via wireless communication channel56established between client electronic device40and wireless access point (i.e., WAP)58, which is shown directly coupled to network14. WAP58may be, for example, an IEEE 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, Wi-Fi®, RFID, and/or Bluetooth™ (including Bluetooth™ Low Energy) device that is capable of establishing wireless communication channel56between client electronic device40and WAP58. Client electronic device42is shown wirelessly coupled to network14via wireless communication channel60established between client electronic device42and cellular network/bridge62, which is shown by example directly coupled to network14.

In some implementations, some or all of the IEEE 802.11x specifications may use Ethernet protocol and carrier sense multiple access with collision avoidance (i.e., CSMA/CA) for path sharing. The various 802.11x specifications may use phase-shift keying (i.e., PSK) modulation or complementary code keying (i.e., CCK) modulation, for example. Bluetooth™ (including Bluetooth™ Low Energy) is a telecommunications industry specification that allows, e.g., mobile phones, computers, smart phones, and other electronic devices to be interconnected using a short-range wireless connection. Other forms of interconnection (e.g., Near Field Communication (NFC)) may also be used.

In some implementations, various I/O requests (e.g., I/O request15) may be sent from, e.g., client applications22,24,26,28to, e.g., computer12. Examples of I/O request15may include but are not limited to, data write requests (e.g., a request that content be written to computer12) and data read requests (e.g., a request that content be read from computer12).

Data Storage System:

Referring also to the example implementation ofFIGS.2-3(e.g., where computer12may be configured as a data storage system), computer12may include storage processor100and a plurality of storage targets (e.g., storage targets102,104,106,108,110). In some implementations, storage targets102,104,106,108,110may include any of the above-noted storage devices. In some implementations, storage targets102,104,106,108,110may be configured to provide various levels of performance and/or high availability. For example, storage targets102,104,106,108,110may be configured to form a non-fully-duplicative fault-tolerant data storage system (such as a non-fully-duplicative RAID data storage system), examples of which may include but are not limited to: RAID 3 arrays, RAID 4 arrays, RAID 5 arrays, and/or RAID 6 arrays. It will be appreciated that various other types of RAID arrays may be used without departing from the scope of the present disclosure.

While in this particular example, computer12is shown to include five storage targets (e.g., storage targets102,104,106,108,110), this is for example purposes only and is not intended limit the present disclosure. For instance, the actual number of storage targets may be increased or decreased depending upon, e.g., the level of redundancy/performance/capacity required.

Further, the storage targets (e.g., storage targets102,104,106,108,110) included with computer12may be configured to form a plurality of discrete storage arrays. For instance, and assuming for example purposes only that computer12includes, e.g., ten discrete storage targets, a first five targets (of the ten storage targets) may be configured to form a first RAID array and a second five targets (of the ten storage targets) may be configured to form a second RAID array.

In some implementations, one or more of storage targets102,104,106,108,110may be configured to store coded data (e.g., via storage management process21), wherein such coded data may allow for the regeneration of data lost/corrupted on one or more of storage targets102,104,106,108,110. Examples of such coded data may include but is not limited to parity data and Reed-Solomon data. Such coded data may be distributed across all of storage targets102,104,106,108,110or may be stored within a specific storage target.

Examples of storage targets102,104,106,108,110may include one or more data arrays, wherein a combination of storage targets102,104,106,108,110(and any processing/control systems associated with storage management application21) may form data array112.

The manner in which computer12is implemented may vary depending upon e.g., the level of redundancy/performance/capacity required. For example, computer12may be configured as a SAN (i.e., a Storage Area Network), in which storage processor100may be, e.g., a dedicated computing system and each of storage targets102,104,106,108,110may be a RAID device. An example of storage processor100may include but is not limited to a VPLEX™, VNX™, TRIDENT™, or Unity™ system offered by Dell EMC™ of Hopkinton, Mass.

In the example where computer12is configured as a SAN, the various components of computer12(e.g., storage processor100, and storage targets102,104,106,108,110) may be coupled using network infrastructure114, examples of which may include but are not limited to an Ethernet (e.g., Layer 2 or Layer 3) network, a fiber channel network, an InfiniBand network, or any other circuit switched/packet switched network.

As discussed above, various I/O requests (e.g., I/O request15) may be generated. For example, these I/O requests may be sent from, e.g., client applications22,24,26,28to, e.g., computer12. Additionally/alternatively (e.g., when storage processor100is configured as an application server or otherwise), these I/O requests may be internally generated within storage processor100(e.g., via storage management process21). Examples of I/O request15may include but are not limited to data write request116(e.g., a request that content118be written to computer12) and data read request120(e.g., a request that content118be read from computer12).

In some implementations, during operation of storage processor100, content118to be written to computer12may be received and/or processed by storage processor100(e.g., via storage management process21). Additionally/alternatively (e.g., when storage processor100is configured as an application server or otherwise), content118to be written to computer12may be internally generated by storage processor100(e.g., via storage management process21).

As discussed above, the instruction sets and subroutines of storage management application21, which may be stored on storage device16included within computer12, may be executed by one or more processors and one or more memory architectures included with computer12. Accordingly, in addition to being executed on storage processor100, some or all of the instruction sets and subroutines of storage management application21(and/or backend process10) may be executed by one or more processors and one or more memory architectures included with data array112.

In some implementations, storage processor100may include front end cache memory system122. Examples of front end cache memory system122may include but are not limited to a volatile, solid-state, cache memory system (e.g., a dynamic RAM cache memory system), a non-volatile, solid-state, cache memory system (e.g., a flash-based, cache memory system), and/or any of the above-noted storage devices.

In some implementations, storage processor100may initially store content118within front end cache memory system122. Depending upon the manner in which front end cache memory system122is configured, storage processor100(e.g., via storage management process21) may immediately write content118to data array112(e.g., if front end cache memory system122is configured as a write-through cache) or may subsequently write content118to data array112(e.g., if front end cache memory system122is configured as a write-back cache).

In some implementations, one or more of storage targets102,104,106,108,110may include a backend cache memory system. Examples of the backend cache memory system may include but are not limited to a volatile, solid-state, cache memory system (e.g., a dynamic RAM cache memory system), a non-volatile, solid-state, cache memory system (e.g., a flash-based, cache memory system), and/or any of the above-noted storage devices.

As discussed above, one or more of storage targets102,104,106,108,110may be a RAID device. For instance, and referring also toFIG.3, there is shown example target150, wherein target150may be one example implementation of a RAID implementation of, e.g., storage target102, storage target104, storage target106, storage target108, and/or storage target110. An example of target150may include but is not limited to a VPLEX™, VNX™, TRIDENT™, or Unity™ system offered by Dell EMC™ of Hopkinton, Mass. Examples of storage devices154,156,158,160,162may include one or more electro-mechanical hard disk drives, one or more solid-state/flash devices, and/or any of the above-noted storage devices. It will be appreciated that while the term “disk” or “drive” may be used throughout, these may refer to and be used interchangeably with any types of appropriate storage devices as the context and functionality of the storage device permits.

In some implementations, target150may include storage processor152and a plurality of storage devices (e.g., storage devices154,156,158,160,162). Storage devices154,156,158,160,162may be configured to provide various levels of performance and/or high availability (e.g., via storage management process21). For example, one or more of storage devices154,156,158,160,162(or any of the above-noted storage devices) may be configured as a RAID 0 array, in which data is striped across storage devices. By striping data across a plurality of storage devices, improved performance may be realized. However, RAID 0 arrays may not provide a level of high availability. Accordingly, one or more of storage devices154,156,158,160,162(or any of the above-noted storage devices) may be configured as a RAID 1 array, in which data is mirrored between storage devices. By mirroring data between storage devices, a level of high availability may be achieved as multiple copies of the data may be stored within storage devices154,156,158,160,162.

While storage devices154,156,158,160,162are discussed above as being configured in a RAID 0 or RAID 1 array, this is for example purposes only and not intended to limit the present disclosure, as other configurations are possible. For example, storage devices154,156,158,160,162may be configured as a RAID 3, RAID 4, RAID 5 or RAID 6 array.

While in this particular example, target150is shown to include five storage devices (e.g., storage devices154,156,158,160,162), this is for example purposes only and not intended to limit the present disclosure. For instance, the actual number of storage devices may be increased or decreased depending upon, e.g., the level of redundancy/performance/capacity required.

In some implementations, one or more of storage devices154,156,158,160,162may be configured to store (e.g., via storage management process21) coded data, wherein such coded data may allow for the regeneration of data lost/corrupted on one or more of storage devices154,156,158,160,162. Examples of such coded data may include but are not limited to parity data and Reed-Solomon data. Such coded data may be distributed across all of storage devices154,156,158,160,162or may be stored within a specific storage device.

The manner in which target150is implemented may vary depending upon e.g., the level of redundancy/performance/capacity required. For example, target150may be a RAID device in which storage processor152is a RAID controller card and storage devices154,156,158,160,162are individual “hot-swappable” hard disk drives. Another example of target150may be a RAID system, examples of which may include but are not limited to an NAS (i.e., Network Attached Storage) device or a SAN (i.e., Storage Area Network).

In some implementations, storage target150may execute all or a portion of storage management application21. The instruction sets and subroutines of storage management application21, which may be stored on a storage device (e.g., storage device164) coupled to storage processor152, may be executed by one or more processors and one or more memory architectures included with storage processor152. Storage device164may include but is not limited to any of the above-noted storage devices.

As discussed above, computer12may be configured as a SAN, wherein storage processor100may be a dedicated computing system and each of storage targets102,104,106,108,110may be a RAID device. Accordingly, when storage processor100processes data requests116,120, storage processor100(e.g., via storage management process21) may provide the appropriate requests/content (e.g., write request166, content168and read request170) to, e.g., storage target150(which is representative of storage targets102,104,106,108and/or110).

In some implementations, during operation of storage processor152, content168to be written to target150may be processed by storage processor152(e.g., via storage management process21). Storage processor152may include cache memory system172. Examples of cache memory system172may include but are not limited to a volatile, solid-state, cache memory system (e.g., a dynamic RAM cache memory system) and/or a non-volatile, solid-state, cache memory system (e.g., a flash-based, cache memory system). During operation of storage processor152, content168to be written to target150may be received by storage processor152(e.g., via storage management process21) and initially stored (e.g., via storage management process21) within front end cache memory system172.

The Backend Service:

As noted above, generally, consider an application that manages a set of logical objects corresponding to some physical entities with substantial response times such as network elements or hardware components. In the example, systems may typically maintain a set of NVMe/TCP ports, each one communicating with a centralized discovery controller over mDNS protocol in conjunction with a TCP/IP based kickstart protocol. Such an application could be split into several micro-services. In the example, it may make sense to split the network interaction, including various protocol messaging, into a “backend” service. The remaining logic, namely the “frontend” service, controls the backend service using some management commands, e.g., add, remove, update commands. Additionally, the system may periodically query the object's state using query command.

In order to implement the above management protocol, standard RPC messaging systems may be suitable. For simplicity, assume that the frontend service is the initiator of all commands while the backend service is a responder only. Thus, add, remove, update are “push” commands, while query is a “pull” command. For each command, the backend service may process the command and reply when finished. The complication may be, e.g., that some commands may block for a substantial period of time so the RPC reply can be delayed. It may be possible to have the backend service queue the incoming commands and process them in the background. This way, RPC is non-blocking, but the command processing is delayed. This is the case, for instance, with the remove command in the example. Notice that during the delete processing, the backend service may still reply queries regarding the object being deleted as if it still exists. Moreover, if a subsequent add command arrives on the same object, the backend service may refuse to add this port as the same port still exists and even may confuse the frontend service by adding the stale object information to query replies. Therefore, as will be discussed in greater detail below, the present disclosure may show how to provide non-blocking RPC add, remove, update commands with the micro-services maintaining a mutually consistent view of the objects.

Discussed below is a more formal description of the model, followed by an existing method for realizing this model, and then a new method that addresses the issue(s) described above. For instance, consider a set of managed logical objects corresponding to some physical entities. Assume that these entities have substantial bringup and teardown delays. Further assume that objects may be dynamically added, removed or updated at any moment. For each managed object, its present state should be exposed through the system GUI. Managed object state consists of a status that may be either ACTIVE or INACTIVE and system specific managed object information.

Consider an application whose job is to manage the above set of objects. It should handle user add remove and update commands. It should periodically query all managed object states and update the system GUI if needed. The above application may be split into 2 services, namely, the high level frontend service and the low level backend service. The frontend service may expose the managed objects to the rest of the system. That is, it accepts user commands, converts them to the format understandable to the backend service, sends them and waits for a response. It periodically queries the backend service for managed object states and updates the system GUI if needed. The backend service may take care of the communication with the underlying physical objects. It accepts and executes commands sent by the frontend service. It replies to managed object states queries.

The management protocol, namely the communication protocol between the frontend service and the backend service may differ between systems, but normally a simple RPC over TCP/IP socket should suffice. For simplicity, assume that the frontend service is the initiator and the backend service is the responder. The commands may include, e.g., add, remove, update, query commands.

Normally, syncing managed object states between the frontend service and the backend service is done as follows: The frontend service sends a message and blocks until it receives a reply. The backend service receives a command, executes it and replies when finished. As add, remove, update commands may block, frontend service may as well block waiting for the backend service reply. Note that the system generally cannot easily distinguish between a delayed reply and a network outage or backend service crash. Another problem is that the system generally cannot query managed object states while waiting for backend service reply. Thus, the state exposed through system GUI may become out of date. Therefore, as will be discussed below, a new method for syncing managed object states is disclosed, where the management protocol becomes non-blocking, resulting in the above-noted example and non-limiting problems being eliminated.

As discussed above and referring also at least to the example implementations ofFIGS.4-5, backend service10may execute400, by a computing device, a management task by a backend service, wherein the management task does not block on managed object response delays of a plurality of managed objects. Backend service10may execute402a maintenance task per managed object of the plurality of managed objects by the backend service, wherein the maintenance task may be a background task that blocks on respective managed object delays.

In some implementations, backend service10may execute400, by a computing device, a management task by a backend service, wherein the management task does not block on managed object response delays of a plurality of managed objects, and in some implementations, backend service10may execute402a maintenance task per managed object of the plurality of managed objects by the backend service, wherein the maintenance task may be a background task that blocks on respective managed object delays. For example, backend service10or part of it may execute400and run a single management task and may execute402and run a maintenance task per managed object.

In some implementations, the management task may process user commands, wherein the user commands may include at least one of an add command, an update command, a remove command, and a query command. For example, the management task may process (e.g., via the backend service10) user commands, which may typically include, e.g., add, remove, update, and/or query. Note that the management task does not block on managed object response delays. The maintenance tasks, discussed further below, may be background tasks that block on respective managed object delays.

In some implementations, all code of the backend service may run in a single thread that includes a scheduler. For example, thread safety and locking is not discussed, as some example implementations, such as the present use case, may employ async await technology. As a result, all code may be running in a single thread that includes a scheduler, which provides cooperative multitasking. For example, the scheduler may pick up a task every time and run it. Tasks may yield voluntarily so that other task may run. However, it should be noted that multi-threading may also be used instead but it may be more complicated (as locking is needed) and less efficient (as threads may be expensive). This may greatly reduce thread safety concerns and may eliminate the need for locking. In the example use case (which should be taken for example purposes only), the present disclosure may be used where the system has a set of NVME/TCP ports. The communication may use any appropriate protocols. Some example protocols may use multicast UDP messaging while others may use TCP/IP messaging. Both such protocols may use timeouts and retransmits. The backend service10may obtain the relevant IP address, port and nqn string. The frontend service may pull this information through the query command (e.g., via backend service10) and communicate it to the upstream system manager module of backend service10and/or storage management application21. Note that the present disclosure should not be limited to this use case. For instance, the present disclosure may be used to monitor hardware objects or any other objects with slow response times, such as SSDs. Thus, the present disclosure may be used wherever objects need to be managed that may have a long/slow response times.

In some implementations, and referring at least to the example implementation ofFIG.5, an example data structure500of a managed object (for processing the above-noted user commands) is shown. In the example, maintenance and/or management task information structures (e.g., data structure500) may be stored in RAM or other system memory by backend service10in a hash table keyed by object ID; however it will be appreciated that other data structures, data stores, storage devices and system memory, and storage location techniques may be used without departing from the scope of the present disclosure. As shown inFIG.5, example and non-limiting fields for data structure500(which may be stored in RAM or other system memory) may include, e.g.:

“ID”502(which may be differently labeled without departing from the scope of the present disclosure), may be the object ID of a corresponding managed object in the system memory.

“update”504(which may be differently labeled without departing from the scope of the present disclosure), may contain update request details of the corresponding managed object. Generally, when non-null, an outstanding update request exists. Example update request details may include a managed object instance with whatever information the object may have, such as name, IP address, etc.

“is_disconnecting”506, may be a flag (which may be differently labeled without departing from the scope of the present disclosure) and may indicate whether an outstanding disconnect request exists for the corresponding managed object. For instance, when an object is to be removed and the removal is in progress, the “disconnecting” is set so it is known removal is in progress. If subsequent add/remove/update arrives, it may need to be known if there is a removal in progress or not.

“conn”508(which may be differently labeled without departing from the scope of the present disclosure) may be the connection object. Generally, if non-null, an active connection to the underlying physical object (i.e., of the corresponding managed object) exists in the system memory.

Regarding the management task, for each command directed towards a corresponding object ID, backend service10may extract the corresponding object ID (e.g., object ID502from data structure500). In some implementations, e.g., for add or update commands, backend service10may override404the update command if an ID (e.g., object ID502) associated with a managed object of the plurality of managed objects exists in data structure (e.g., data structure500) stored in a system memory (e.g., via storage device16), and a first flag may be unset in data structure500. For example, if a particular ID exists in the system memory (e.g., hash table), backend service10may override update504and unset is_disconnecting506. For instance, first the add command may arrive. While add is in progress, update command with the same ID arrives. Another example is remove command arrives. While remove is in progress, add command with the same ID arrives.

In some implementations, when the management task is one of the add command and the update command, backend service10may add406an entry for the ID in data structure500to be stored in the system memory if the ID associated with the managed object of the plurality of managed objects does not exist, and may start a new maintenance task for the ID. For example, if there is no entry for the particular ID in the system memory, backend service10may add an entry in the hash table with ID502as the key used for the storage location of the newly added data structure in the hash table, and may start a new maintenance task corresponding to the ID.

As noted above, normally, prior systems that synchronize managed object states between the frontend service and the backend service do it as follows: The frontend service sends a message and blocks until it receives a reply. The backend service receives a command, executes it and replies when finished. As add, remove, update commands may block, frontend service may as well block waiting for the backend service reply. Note that the system generally cannot easily distinguish between a delayed reply and a network outage or backend service crash. Another problem is that the system generally cannot query managed object states while waiting for backend service reply. Thus, the state exposed through system GUI may become out of date. Therefore, as backend service10has a new and non-blocking method for syncing managed object states, the management protocol becomes non-blocking, resulting in the above-noted example and non-limiting problems being eliminated. For instance, in some implementations, when the management task is one of the add command and the update command, backend service10may trigger408an event for the maintenance task corresponding to the ID. For example, backend service10may trigger an event for a maintenance task corresponding to the ID. Generally, the object corresponding to the ID may not be used when being changed (e.g., added/updated), and therefore, the object should be continuously queried by backend service10to see when the object is free; however, the object itself is not blocked (i.e., non-blocking).

In some implementations, e.g., for the remove command, backend service10may set410a first flag and unset a second flag if an ID associated with a managed object of the plurality of managed objects exists in data structure500stored in the system memory and the first flag is unset. For example, for the remove command, if the ID exists in the hash table and is_disconnected506is unset, backend service10may set is_disconnecting506and unset update504, and may also trigger408an event for the maintenance task corresponding to the ID. That is, backend service10may trigger an event for the maintenance task corresponding to ID502. The scheduler may be used to schedule these triggered events. For example, the maintenance task may yield the control and wait for an event. This is generally how cooperative multitasking works. Event means wake up the maintenance task corresponding to ID and let the scheduler run it.

In some implementations, e.g., for the query command, backend service10may collect412information of all the plurality of managed objects. That is, backend service10may collect the information of all managed objects in the example hash table. Additionally, backend service10may set414a status set for each respective managed object of the plurality of managed objects to active if the respective managed object is idle, and may set the status for each respective managed object of the plurality of managed objects to inactive if the respective managed object is not idle. For instance, for each collected managed object, backend service10may set its respective status to ACTIVE if idle, namely, not blocked on response delay, and may set its respective status to INACTIVE if not idle. This information may be collected by the query and is normally presented in the system GUI.

Regarding the maintenance task, backend service10may remove416information from the system memory based upon, at least in part, information in the data structure stored in the system memory. For example, if is_disconnected506is unset and conn508is null, and update504is null, backend service10may remove the information from the hash table and stop. For example, if a managed object was deleted and there are no pending events related to it, the system may no longer care about it and may proceed to clean up after it.

In some implementations, backend service10may tear down418a connection based upon, at least in part, information in the data structure stored in the system memory. For example, if is_disconnected506is set, backend service10may teardown the connection and unset is_disconnected506and conn508when done. Note that the teardown operation is blocking.

In some implementations, backend service10may bring up420a new connection based upon, at least in part, information in the data structure stored in the system memory. For example, if update504is set, backend service10may teardown the connection if conn508is set, may bring up a new connection and set conn508. Note that both teardown and bring up operations are blocking. backend service10may wait for an event (e.g., a triggering event) and start over. This may occur because a new object is being stored.