System and method for on-demand recovery points

An illustrative embodiment disclosed herein is an apparatus including a processor having programmed instructions to determine a frequency rate for tracking changed data of a virtual machine (VM), track the changed data at the determined frequency rate, receive a request to generate a recovery point associated with a specified time, and, responsive to receiving the request to generate the recovery point associated with the specified time, generate the recovery point.

BACKGROUND

Virtual computing systems are widely used in a variety of applications. Virtual computing systems include one or more host machines running one or more virtual machines concurrently. The virtual machines utilize the hardware resources of the underlying host machines. Each virtual machine may be configured to run an instance of an operating system. Modern virtual computing systems allow several operating systems and several software applications to be safely run at the same time on the virtual machines of a single host machine, thereby increasing resource utilization and performance efficiency. However, the present day virtual computing systems have limitations due to their configuration and the way they operate.

SUMMARY

Aspects of the present disclosure relate generally to a virtualization environment, and more particularly to a system and method for recovering an entity on-demand.

An illustrative embodiment disclosed herein is an apparatus including a processor having programmed instructions to determine a frequency rate for tracking changed data of a virtual machine (VM), track the changed data at the determined frequency rate, receive a request to generate a recovery point associated with a specified time, and, responsive to receiving the request to generate the recovery point associated with the specified time, generate the recovery point.

Another illustrative embodiment disclosed herein is a non-transitory computer-readable storage medium having instructions stored thereon that, upon execution by a processor, causes the processor to perform operations comprising determining a frequency rate for tracking changed data of a virtual machine (VM), tracking the changed data at the determined frequency rate, receiving a request to generate a recovery point associated with a specified time, and, responsive to receiving the request to generate the recovery point associated with the specified time, generating the recovery point.

Another illustrative embodiment disclosed herein is a computer-implemented method comprising determining a frequency rate for tracking changed data of a virtual machine (VM), tracking the changed data at the determined frequency rate, receiving a request to generate a recovery point associated with a specified time, and, responsive to receiving the request to generate the recovery point associated with the specified time, generating the recovery point.

Further details of aspects, objects, and advantages of the invention are described below in the detailed description, drawings, and claims. Both the foregoing general description and the following detailed description are exemplary and explanatory, and are not intended to be limiting as to the scope of the invention. Particular embodiments may include all, some, or none of the components, elements, features, functions, operations, or steps of the embodiments disclosed above. The subject matter which can be claimed comprises not only the combinations of features as set out in the attached claims but also any other combination of features in the claims, wherein each feature mentioned in the claims can be combined with any other feature or combination of other features in the claims. Furthermore, any of the embodiments and features described or depicted herein can be claimed in a separate claim and/or in any combination with any embodiment or feature described or depicted herein or with any of the features of the attached claims.

DETAILED DESCRIPTION

Data recovery or backup typically relies on a schedule to create snapshots that are recovery points for the entity being protected. The snapshots may capture the state of the entity at pre-determined points in time as specified in the schedule. When the user needs to recover or clone an entity, a list of snapshots may be presented for the user to pick. In the conventional approach, the user has to select a recovery point from the list of snapshots. As systems become capable of lower recovery point objective (RPO), the number of snapshots presented to the user to pick from is large and becomes unusable. The resources required by the storage system to maintain and manage the large number of potential recovery points adds cost and complexity. What is needed is an on-demand recovery system.

In some embodiments of the disclosure presented herein, generation of the recovery point may be deferred. In some embodiments, a storage system may track changes to an entity. In some embodiments, when the user needs to restore and/or clone an entity, the user may specify a time associated with data from which the entity is restored and/or cloned. The storage system may track changes to the data made by the entity using an internal low cost and/or low overhead mechanism, such as a file system journal. This change tracking may be autonomously performed by the storage system at a pre-determined frequency that may be determined by the storage system based on system resources and change rate. At the time of recovery, the storage system may generate the recovery point on-demand using the appropriate tracked changes that are determined via the user's time input. The storage system may enable the restore and/or clone operation.

In some embodiments of the present disclosure, the storage system provides an provides an intuitive way to consider restoring data by allowing a user to specify a date and time to roll back to and then have the system automatically create a restore point that corresponds to that date and time. The storage system may not instantiate the recovery point until the user requests the date and time to restore. Some embodiments of the present disclosure allow for less overhead by not generating recovery points that will never be requested by the customer and that will end up aging out according to a schedule and never actually used. The storage system does not require the user to scroll through a list of snapshots to find the desired restore point. Furthermore, the storage system does not save data associated with the change tracking mechanism. Thus, the storage system can be leveraged to track data at a higher frequency and retain the data for a longer time than the conventional systems, given the same amount of system resources.

Virtualization Technology and Environment

Referring now toFIG. 1, a virtual computing system100is shown, in accordance with some embodiments of the present disclosure. The virtual computing system100includes a plurality of nodes, such as a first node105, a second node110, and a third node115. Each of the first node105, the second node110, and the third node115may also be referred to as a “host” or “host machine.” The first node105includes user virtual machines (“user VMs”)120A and120B (collectively referred to herein as “user VMs120”), a hypervisor125configured to create and run the user VMs, and a controller VM130configured to manage, route, and otherwise handle workflow requests between the various nodes of the virtual computing system100. Similarly, the second node110includes user VMs135A and135B (collectively referred to herein as “user VMs135”), a hypervisor140, and a controller VM145, and the third node115includes user VMs150A and150B (collectively referred to herein as “user VMs150”), a hypervisor155, and a controller VM160. The controller VM130, the controller VM145, and the controller VM160are all connected to a network165to facilitate communication between the first node105, the second node110, and the third node115. Although not shown, in some embodiments, the hypervisor125, the hypervisor140, and the hypervisor155may also be connected to the network165.

The virtual computing system100also includes a storage pool170. The storage pool170may include network-attached storage (NAS)175and direct-attached storage (DAS)180A,180B, and180C (collectively referred to herein as DAS180). The NAS175is accessible via the network165and, in some embodiments, may include cloud storage185, as well as local storage area network190(also referred to as networked storage190). In contrast to the NAS175, which is accessible via the network165, the DAS180includes storage components that are provided internally within each of the first node105, the second node110, and the third node115, respectively, such that each of the first, second, and third nodes may access its respective DAS without having to access the network165.

It is to be understood that only certain components of the virtual computing system100are shown inFIG. 1. Nevertheless, several other components that are needed or desired in the virtual computing system100to perform the functions described herein are contemplated and considered within the scope of the present disclosure.

Although three of the plurality of nodes (e.g., the first node105, the second node110, and the third node115) are shown in the virtual computing system100, in other embodiments, greater than or fewer than three nodes may be used. Likewise, although only two of the user VMs (e.g., the user VMs120, the user VMs135, and the user VMs150) are shown on each of the respective first node105, the second node110, and the third node115, in other embodiments, the number of the user VMs on each of the first, second, and third nodes may vary to include either a single user VM or more than two user VMs. Further, the first node105, the second node110, and the third node115need not always have the same number of the user VMs (e.g., the user VMs120, the user VMs135, and the user VMs150).

In some embodiments, each of the first node105, the second node110, and the third node115may be a hardware device, such as a server. For example, in some embodiments, one or more of the first node105, the second node110, and the third node115may be an NX-1000 server, NX-3000 server, NX-6000 server, NX-8000 server, etc. provided by Nutanix, Inc. or server computers from Dell, Inc., Lenovo Group Ltd. or Lenovo PC International, Cisco Systems, Inc., etc. In other embodiments, one or more of the first node105, the second node110, or the third node115may be another type of hardware device, such as a personal computer, an input/output or peripheral unit such as a printer, or any type of device that is suitable for use as a node within the virtual computing system100. In some embodiments, the virtual computing system100may be part of a data center.

Each of the first node105, the second node110, and the third node115may also be configured to communicate and share resources with each other via the network165. For example, in some embodiments, the first node105, the second node110, and the third node115may communicate and share resources with each other via the controller VM130, the controller VM145, and the controller VM160, and/or the hypervisor125, the hypervisor140, and the hypervisor155. One or more of the first node105, the second node110, and the third node115may be organized in a variety of network topologies.

Also, the first node105may include one or more processing units192A, the second node110may include one or more processing units192B, and the third node115may include one or more processing units192C. The processing units192A,192B, and192C are collectively referred to herein as the processing units192. The processing units192may be configured to execute instructions. The instructions may be carried out by a special purpose computer, logic circuits, or hardware circuits of the first node105, the second node110, and the third node115. The processing units192may be implemented in hardware, firmware, software, or any combination thereof. The term “execution” is, for example, the process of running an application or the carrying out of the operation called for by an instruction. The instructions may be written using one or more programming language, scripting language, assembly language, etc. The processing units192, thus, execute an instruction, meaning that they perform the operations called for by that instruction.

The processing units192may be operably coupled to the storage pool170, as well as with other elements of the first node105, the second node110, and the third node115to receive, send, and process information, and to control the operations of the underlying first, second, or third node. The processing units192may retrieve a set of instructions from the storage pool170, such as, from a permanent memory device like a read only memory (“ROM”) device and copy the instructions in an executable form to a temporary memory device that is generally some form of random access memory (“RAM”). The ROM and RAM may both be part of the storage pool170, or in some embodiments, may be separately provisioned from the storage pool. The RAM may be stand-alone hardware such as RAM chips or modules. Further, each of the processing units192may include a single stand-alone processing unit, or a plurality of processing units that use the same or different processing technology.

With respect to the storage pool170and particularly with respect to the DAS180, each of the DAS180may include a variety of types of memory devices. For example, in some embodiments, one or more of the DAS180may include, but is not limited to, any type of RAM, ROM, flash memory, magnetic storage devices (e.g., hard disk, floppy disk, magnetic strips, etc.), optical disks (e.g., compact disk (“CD”), digital versatile disk (“DVD”), etc.), smart cards, solid state devices, etc. Likewise, the NAS175may include any of a variety of network accessible storage (e.g., the cloud storage185, the local storage area network190, etc.) that is suitable for use within the virtual computing system100and accessible via the network165. The storage pool170, including the NAS175and the DAS180, together form a distributed storage system configured to be accessed by each of the first node105, the second node110, and the third node115via the network165, the controller VM130, the controller VM145, the controller VM160, and/or the hypervisor125, the hypervisor140, and the hypervisor155. In some embodiments, the various storage components in the storage pool170may be configured as virtual disks for access by the user VMs120, the user VMs135, and the user VMs150.

Each of the user VMs120, the user VMs135, and the user VMs150is a software-based implementation of a computing machine in the virtual computing system100. The user VMs120, the user VMs135, and the user VMs150emulate the functionality of a physical computer. Specifically, the hardware resources, such as processing unit, memory, storage, etc., of the underlying computer (e.g., the first node105, the second node110, and the third node115) are virtualized or transformed by the respective hypervisor125, the hypervisor140, and the hypervisor155, into the underlying support for each of the user VMs120, the user VMs135, and the user VMs150that may run its own operating system and applications on the underlying physical resources just like a real computer. By encapsulating an entire machine, including CPU, memory, operating system, storage devices, and network devices, the user VMs120, the user VMs135, and the user VMs150are compatible with most standard operating systems (e.g. Windows, Linux, etc.), applications, and device drivers. Thus, each of the hypervisor125, the hypervisor140, and the hypervisor155is a virtual machine monitor that allows a single physical server computer (e.g., the first node105, the second node110, third node115) to run multiple instances of the user VMs120, the user VMs135, and the user VMs150, with each user VM sharing the resources of that one physical server computer, potentially across multiple environments. By running the user VMs120, the user VMs135, and the user VMs150on each of the first node105, the second node110, and the third node115, respectively, multiple workloads and multiple operating systems may be run on a single piece of underlying hardware computer (e.g., the first node, the second node, and the third node) to increase resource utilization and manage workflow.

The user VMs120, the user VMs135, and the user VMs150are controlled and managed by their respective instance of the controller VM130, the controller VM145, and the controller VM160. The controller VM130, the controller VM145, and the controller VM160are configured to communicate with each other via the network165to form a distributed system195. Each of the controller VM130, the controller VM145, and the controller VM160may also include a local management system configured to manage various tasks and operations within the virtual computing system100. For example, in some embodiments, the local management system may perform various management related tasks on the user VMs120, the user VMs135, and the user VMs150.

The hypervisor125, the hypervisor140, and the hypervisor155of the first node105, the second node110, and the third node115, respectively, may be configured to run virtualization software, such as, ESXi from VMWare, AHV from Nutanix, Inc., XenServer from Citrix Systems, Inc., etc. The virtualization software on the hypervisor125, the hypervisor140, and the hypervisor155may be configured for running the user VMs120, the user VMs135, and the user VMs150, respectively, and for managing the interactions between those user VMs and the underlying hardware of the first node105, the second node110, and the third node115. Each of the controller VM130, the controller VM145, the controller VM160, the hypervisor125, the hypervisor140, and the hypervisor155may be configured as suitable for use within the virtual computing system100.

The network165may include any of a variety of wired or wireless network channels that may be suitable for use within the virtual computing system100. For example, in some embodiments, the network165may include wired connections, such as an Ethernet connection, one or more twisted pair wires, coaxial cables, fiber optic cables, etc. In other embodiments, the network165may include wireless connections, such as microwaves, infrared waves, radio waves, spread spectrum technologies, satellites, etc. The network165may also be configured to communicate with another device using cellular networks, local area networks, wide area networks, the Internet, etc. In some embodiments, the network165may include a combination of wired and wireless communications.

Referring still toFIG. 1, in some embodiments, one of the first node105, the second node110, or the third node115may be configured as a leader node. The leader node may be configured to monitor and handle requests from other nodes in the virtual computing system100. For example, a particular user VM (e.g., the user VMs120, the user VMs135, or the user VMs150) may direct an input/output request to the controller VM (e.g., the controller VM130, the controller VM145, or the controller VM160, respectively) on the underlying node (e.g., the first node105, the second node110, or the third node115, respectively). Upon receiving the input/output request, that controller VM may direct the input/output request to the controller VM (e.g., one of the controller VM130, the controller VM145, or the controller VM160) of the leader node. In some cases, the controller VM that receives the input/output request may itself be on the leader node, in which case, the controller VM does not transfer the request, but rather handles the request itself.

The controller VM of the leader node may fulfil the input/output request (and/or request another component within the virtual computing system100to fulfil that request). Upon fulfilling the input/output request, the controller VM of the leader node may send a response back to the controller VM of the node from which the request was received, which in turn may pass the response to the user VM that initiated the request. In a similar manner, the leader node may also be configured to receive and handle requests (e.g., user requests) from outside of the virtual computing system100. If the leader node fails, another leader node may be designated.

Furthermore, one or more of the first node105, the second node110, and the third node115may be combined together to form a network cluster (also referred to herein as simply “cluster.”) Generally speaking, all of the nodes (e.g., the first node105, the second node110, and the third node115) in the virtual computing system100may be divided into one or more clusters. One or more components of the storage pool170may be part of the cluster as well. For example, the virtual computing system100as shown inFIG. 1may form one cluster in some embodiments. Multiple clusters may exist within a given virtual computing system (e.g., the virtual computing system100). The user VMs120, the user VMs135, and the user VMs150that are part of a cluster are configured to share resources with each other. In some embodiments, multiple clusters may share resources with one another.

Additionally, in some embodiments the virtual computing system100includes a central management system197that is configured to manage and control the operation of the various clusters in the virtual computing system. In some embodiments, the central management system197may be configured to communicate with the local management systems on each of the controller VM130, the controller VM145, the controller VM160for controlling the various clusters.

Again, it is to be understood again that only certain components and features of the virtual computing system100are shown and described herein. Nevertheless, other components and features that may be needed or desired to perform the functions described herein are contemplated and considered within the scope of the present disclosure. It is also to be understood that the configuration of the various components of the virtual computing system100described above is only an example and is not intended to be limiting in any way. Rather, the configuration of those components may vary to perform the functions described herein.

VM Cloning in a Software Defined Storage Environment

Referring now toFIG. 2, an example embodiment of a storage system200for on-demand recovery. The storage system200includes a UVM202executing an application204and having read/write access to the data of storage212, including a journal214. The system includes a CVM206including an input/output (I/O) manager208and a recovery manager210. In some embodiments, some or all of the components (e.g. the UVM202, the CVM206, the I/O manager208and/or the recovery manager210) of the storage system200may include one or more processing devices (e.g., the processing unit216). The one or more processing devices may include one or more devices executing operations in response to instructions stored electronically on an electronic storage medium (e.g. the storage212or RAM).

A processing device associated (e.g. the processing unit216) with the I/O manager208may track changes to the data of an entity such as UVM202. For sake of brevity, actions by the processing device associated I/O manager208are referred to as actions by the I/O manager208herein. A change to the data of the UVM202occurs when the UVM202writes data. For example, a processing device associated with the UVM202may write data to the storage212or the RAM responsive to executing the application204. In some embodiments, a processing device associated with the application204may write data to the storage212or the RAM.

The I/O manager208may track changed data (e.g. writes) by appending metadata about the changed data to the journal214. The metadata is referred to herein as markers. Each marker may include a start location of the changed data, a length of the changed data, and/or a time that the marker was appended to the journal214, among others. In some embodiments, a marker may include a plurality of start locations and a plurality of lengths, for example, if the changed data is not logically contiguous. The time that the data changed is referred to herein as a timestamp. In some embodiments, the location of the changed data includes a pointer to the memory address where the data was written to.

In some embodiments, the journal214is a log-based data structure. In this regard, units of metadata are written sequentially to logical addresses of the journal214. For example, if a first unit of metadata is written to a first logical address range X to X+Y, then a second unit of metadata written directly after the first unit of metadata is written to a second logical address range X+Y+1 to X+Y+Z. In some embodiments, the journal214includes an append point that identifies the next available logical address. In some embodiments, the journal is a ring-like data structure. For example, after a first unit of metadata is written to a last logical address of the journal214, the append point indicates that the first logical address of the journal214is the next available logical address. In some embodiments, the journal214may be located in an SSD portion of the storage212. In some embodiments, the journal214may be located in a flash memory portion of the storage212. In some embodiments, the journal214may be located in a single-level cell (SLC) portion of the storage212, a multiple-level cell (MLC) portion of the storage212, or a combination of the two.

In some embodiments, the I/O manager208transfer selected units of metadata in the journal214to a second portion of the storage212. A unit of metadata may be selected for transfer based on one or more criteria such as. In some embodiments, the unit of metadata is selected based on being least recently used metadata. In this regard, the unit of metadata may be selected for transfer based on a length of time starting at a first time when the unit of metadata was written to and ending at current time. The length of time may be compared to a pre-determined length of time. The unit of metadata may be selected based on the length of time satisfying (e.g. being greater than) the pre-determined length of time. In some embodiments, the length of time is reset each time metadata for a changed data is updated. In some embodiments, the unit of metadata is selected for transfer based on a logical distance between a logical address of the unit of metadata and the append point. The logical distance may be compared to a pre-determined logical distance. The unit of metadata may be selected based on the logical distance satisfying the pre-determined logical distance.

In some embodiments, an updated unit of metadata is written to a different logical address than a previous version of the unit of metadata. In some embodiments, an address of the previous version of the unit of metadata may be indicated in the updated unit of data. In some embodiments, the I/O manager208performs a garbage cleanup of the previous versions of any unit of metadata from the journal214. In this regard, the I/O manager208may scan the journal214and re-append the updated units of metadata at a first portion of the journal214and place the append point immediately after the first portion of the journal214.

The I/O manager208may determine a frequency rate for tracking the changed data. The frequency rate may determine how frequent markers are appended to the journal214. For example, if the frequency rate is once per second, then when a write occurs, the I/O manager208may wait until the next second to append the marker. The frequency rate may be determined based on a capability of the system resources. The capability of the system resources may include an amount of storage space in the storage212allocated for the journal214. In some embodiments, the I/O manager208determines a number of UVMs, such as UVM202, for which changed data is tracked. In some embodiments, the number of UVMs for which changed data is tracked is same as the number of UVMs that are assigned to the journal214(or one of a plurality of journals214). The I/O manager208may calculate an amount of available storage space per UVM as a quotient of the amount of available storage space for the journal214and the number of UVMs.

The I/O manager208may estimate an amount of storage space needed for tracking data for one VM. For example, the I/O manager208may estimate a size of a marker (e.g. an entry). The I/O manager208may estimate the size of the marker based on historical data I/O patterns. The estimated size of the marker may vary based on the frequency rate. The I/O manager208may identify a retention period. The retention period may be pre-determined by a policy or a user or dynamically selected by the I/O manager208based on how much data is being written to the corresponding VM at the time the estimation is being performed. The I/O manager208may identify a frequency rate. The I/O manager208may estimate the storage space needed as a product of the estimated size of a marker and the number of markers created in the retention period. The I/O manager208may iterate the estimation for multiple frequency rates. The I/O manager208may determine a maximum frequency rate such that an amount of storage space for tracking data for one VM at the maximum frequency rate is less than (or equal to) the amount of available storage space per VM and an amount of storage space for tracking data for one VM at a frequency rate at one increment higher than the maximum frequency rate is greater than the amount of the available storage space per VM.

In some embodiments, the system200includes a plurality of UVMs202and the storage212includes a plurality of journals214. In some embodiments, each UVM202is assigned a different journal214. In some embodiments, the estimated amount of storage space for tracking data for one UVM202may take into account replication. For example, if a replication policy states that metadata in the journal214for one UVM202is to be replicated to five other journals214assigned to five other UVMs202, then the estimated amount of storage space for tracking data for one UVM202may be six times as much as when there is no replication policy.

The capability of the system resources may include the CPU usage, the memory usage, the I/O usage, among others. The discussion herein is on the CPU usage without departing from the scope of the disclosure. The I/O manager208may determine a baseline CPU usage. The I/O manager may determine a delta CPU usage in order to track changed data at a frequency rate. The I/O manager208may determine a frequency rate such that a total CPU usage (including the baseline CPU usage and the delta CPU usage) does not exceed a predefined CPU usage threshold. In some embodiments, the I/O manager208may determine a frequency rate such that the delta CPU usage does not exceed a second predefined CPU usage threshold, without a priori knowledge of the baseline CPU usage.

The frequency rate may be determined based on a write frequency of the UVM202. The write frequency may be how often the processing device associated with the UVM202and/or the application204writes data. In some embodiments, the write frequency may be a function (e.g. an average, a moving average) of historical write frequency patterns. The historical write frequency patterns may be observed in metadata. In some embodiments, the I/O manager208may determine a frequency rate that does not exceed a combination (e.g. ratio, proportion, or another function) of the write frequency and a predefined number. In some embodiments, the I/O manager208may determine the frequency rate as a lower one of a first frequency rate that does not result in a CPU usage exceeding a predefined CPU usage threshold and a second frequency rate that does not exceed a combination of the write frequency and a predefined number. In some embodiments, the recovery manager210may determine the frequency rate.

A processing device associated (e.g. the processing unit216) with the recovery manager210may receive a specified time associated with a requested recovery. For sake of brevity, actions by the processing device associated with the recovery manager210are referred to as actions by the recovery manager210herein. The recovery manager210may receive the specified time from a user via a user interface or from the system based on rules (e.g. a service level agreement or policy). In some embodiments, the user interface is a part of the recovery manager210. In some embodiments, the user interface is a separate component form the recovery manager210. The recovery manager210may forward the specified time to the I/O manager208.

The I/O manager208may generate a recovery point. In some embodiments, the recovery point may be synthesized from a set of markers that were appended before the specified time. The I/O manager208may determine the set of markers that were appended before the specified time. In some embodiments, the I/O manager208may access the journal214that maps a location of the changed data to a time the marker of the changed data appended to the journal214. The I/O manager208may sort the journal214based on the time the markers were appended. The I/O manager208may select the set of markers from the sorted markers that were appended before the specified time. The I/O manager208may aggregate the set of markers. In some embodiments, two or more markers of the set of markers may track the same changed data. In some embodiments, the I/O manager208may select the later marker of the two or more markers and delete or ignore the earlier marker of the two or more markers. The I/O manager208may send the recovery point to the recovery manager210.

In some embodiments, I/O manager208synthesizes (e.g. generates) the recovery point from a baseline snapshot and the changed data corresponding to the set of markers determined by the I/O manager208. For example, the system200generates baseline snapshots every hour and appends markers every minute. If the system200receives a request to synthesize the recovery point at 9:30 AM, the system200fetches the baseline snapshot from 9:00 AM and retrieves the markers tracking the changes from 9:00 AM to 9:30 AM. The system200adds the changed data corresponding with the markers between 9:00 AM to 9:30 AM to the baseline snapshot to synthesize the recovery point. This is different from the copy-and-write technique, where a snapshot, sometimes incremental, is generated every time data is written.

The recovery manager210may apply the recovery point. The recovery manager210may recover and/or clone UVM202on a second VM. In some embodiments, the I/O manager208may apply the recovery point to a second UVM. In some embodiments, the I/O manager208or the recovery manager210deletes the recovery point after the UVM202is recovered and/or cloned.

The UVM202may be an instance of the user VM120awith respect toFIG. 1. The CVM206may be an instance of the controller VM130with respect toFIG. 1. The storage212may be an instance of one or more of the DAS180, the cloud storage185, and/or the local storage190with respect toFIG. 1. The processing unit216may be an instance of the processing unit192A with respect toFIG. 1.

Referring now toFIG. 3, an example method300for on-demand recovery is shown. The method300may be implemented using, or performed by, the components of the storage system200, which is detailed herein with respect toFIG. 2. Additional, fewer, or different operations may be performed in the method300depending on the embodiment. In some embodiments, the method300may be implemented in one or more processing devices (e.g., the processing unit216). The one or more processing devices may include one or more devices executing some or all of the operations of the method300in response to instructions stored electronically on an electronic storage medium (e.g. the storage212or RAM). The one or more processing devices may include one or more devices configured through hardware, firmware, and/or software to be specifically designed for execution of one or more of the operations of the method300.

At operation302, an I/O manager, such as the I/O manager208, may determine a frequency rate for tracking changes of a first VM, such as the UVM202. At operation304, the I/O manager may track the changes at the determined frequency rate. In some embodiments, the I/O manager may append a marker to a data structure, such as the journal214, in an electronic storage medium, such as the storage212. In some embodiments, the I/O manager may determine the frequency rate for tracking the changed data based on system resources of the VM and a write frequency of the VM.

At operation306, the I/O manager may receive a request to generate a recovery point associated with a specified time. In some embodiments, the I/O manager may determine a set of markers appended before the specified time. In some embodiments, the I/O manager may aggregate the set of markers. At operation308, the I/O manager may generate the recovery point on-demand based on the changed data associated with the set of markers and the specified time. In some embodiments, the I/O manager may generate the recovery point on-demand based on a baseline snapshot. In some embodiments, the apply the recovery point to a second VM.

It is to be understood that any examples used herein are simply for purposes of explanation and are not intended to be limiting in any way.