Patent Publication Number: US-2022240405-A1

Title: Controlling status indicators for drive bays of a drive bay enclosure of a storage system

Description:
RELATED APPLICATION 
     The present application claims priority to Chinese Patent Application No. 202110107145.1, filed on Jan. 26, 2021 and entitled “Controlling Status Indicators for Drive Bays of a Drive Bay Enclosure of a Storage System,” which is incorporated by reference herein in its entirety. 
     FIELD 
     The field relates generally to information processing, and more particularly to storage in information processing systems. 
     BACKGROUND 
     Storage arrays and other types of storage systems are often shared by multiple host devices over a network. Applications running on the host devices each include one or more processes that perform the application functionality. Such processes issue input-output (TO) operation requests for delivery to the storage systems. Storage controllers of the storage systems service such requests for IO operations. In some information processing systems, a storage system may include one or more drive bays in which storage devices may be hot-swapped into and out of the storage system. 
     SUMMARY 
     Illustrative embodiments of the present disclosure provide techniques for controlling status indicators for drive bays of a drive bay enclosure of a storage system. 
     In one embodiment, an apparatus comprises at least one processing device comprising a processor coupled to a memory and a drive bay enclosure of a storage system comprising a housing with one or more drive bays, the housing of the drive bay enclosure comprising one or more status indicators proximate an opening for at least a given one of the one or more drive bays. The at least one processing device is configured to perform steps of determining status information for the given drive bay, and controlling the one or more status indicators proximate the opening for the given drive bay based at least in part on the determined status information. 
     These and other illustrative embodiments include, without limitation, methods, apparatus, networks, systems and processor-readable storage media. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of an information processing system for controlling status indicators for drive bays of a drive bay enclosure of a storage system in an illustrative embodiment. 
         FIG. 2  is a flow diagram of an exemplary process for controlling status indicators for drive bays of a drive bay enclosure of a storage system in an illustrative embodiment. 
         FIG. 3A  shows a storage system with a drive enclosure comprising drive bays configured to indicate status information in an illustrative embodiment. 
         FIG. 3B  shows a turnover plate for a drive bay in an illustrative embodiment. 
         FIG. 3C  shows a filler plate for a drive bay in an illustrative embodiment. 
         FIG. 3D  shows a drive tray for a drive bay in an illustrative embodiment. 
         FIG. 4A  show a luminous spindle and lights for turnover plates of drive bays in an illustrative embodiment. 
         FIG. 4B  shows a turnover plate in a folded state in an illustrative embodiment. 
         FIG. 4C  shows a turnover plate in an unfolded state in an illustrative embodiment. 
         FIG. 5  shows a perspective view of a drive enclosure with turnover plates, filler plates and drive trays installed in drive bays thereof in an illustrative embodiment. 
         FIG. 6  shows a front view of a drive enclosure with turnover plates installed in drive bays thereof in an illustrative embodiment. 
         FIG. 7  shows a drive bay of a drive enclosure with an indicator light of a filler plate unlit in an illustrative embodiment. 
         FIG. 8  shows a drive bay of a drive enclosure with an indicator light of a filler plate blinking in an illustrative embodiment. 
         FIG. 9  shows a drive bay of a drive enclosure with an indicator light of a turnover plate blinking in an illustrative embodiment. 
         FIG. 10  shows a drive bay of a drive enclosure with first and second indicator lights of a drive tray blinking simultaneously in an illustrative embodiment. 
         FIG. 11  shows a drive bay of a drive enclosure with a first indicator light of a drive tray blinking and a second indicator light of the drive tray unlit in an illustrative embodiment. 
         FIG. 12  shows a drive bay of a drive enclosure with a first indicator light of a drive tray lit and a second indicator light of the drive tray unlit in an illustrative embodiment. 
         FIG. 13  shows a drive bay of a drive enclosure with a first indicator light of a drive tray unlit and a second indicator light of the drive tray blinking in an illustrative embodiment. 
         FIG. 14  shows a drive bay of a drive enclosure with first and second indicator light of a drive tray blinking in turn in an illustrative embodiment. 
         FIGS. 15 and 16  show examples of processing platforms that may be utilized to implement at least a portion of an information processing system in illustrative embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Illustrative embodiments will be described herein with reference to exemplary information processing systems and associated computers, servers, storage devices and other processing devices. It is to be appreciated, however, that embodiments are not restricted to use with the particular illustrative system and device configurations shown. Accordingly, the term “information processing system” as used herein is intended to be broadly construed, so as to encompass, for example, processing systems comprising cloud computing and storage systems, as well as other types of processing systems comprising various combinations of physical and virtual processing resources. An information processing system may therefore comprise, for example, at least one data center or other type of cloud-based system that includes one or more clouds hosting tenants that access cloud resources. 
       FIG. 1  shows an information processing system  100  configured in accordance with an illustrative embodiment to provide functionality for indicating drive status of drive bays in a drive enclosure of a storage system. The information processing system  100  comprises one or more host devices  102 - 1 ,  102 - 2 , . . .  102 -N (collectively, host devices  102 ) that communicate over a network  104  with one or more storage arrays  106 - 1 ,  106 - 2 , . . .  106 -M (collectively, storage arrays  106 ). The network  104  may comprise a storage area network (SAN). 
     The storage array  106 - 1 , as shown in  FIG. 1 , comprises one or more storage devices  108  that are inserted into a drive bay enclosure  107 . The drive bays of the drive bay enclosure  107  are assumed to comprise hot-swappable drive bays in which the storage devices  108  are mounted or otherwise inserted. The storage devices  108  each store data utilized by one or more applications running on the host devices  102 . The storage devices  108  are illustratively arranged in one or more storage pools, such as one or more software-defined storage (SDS) storage pools. The storage array  106 - 1  also comprises one or more storage controllers  110  that facilitate IO processing for the storage devices  108 . The storage array  106 - 1  and its associated storage devices  108  are an example of what is more generally referred to herein as a “storage system.” This storage system in the present embodiment is shared by the host devices  102 , and is therefore also referred to herein as a “shared storage system.” In embodiments where there is only a single host device  102 , the host device  102  may be configured to have exclusive use of the storage system. 
     The host devices  102  illustratively comprise respective computers, servers or other types of processing devices capable of communicating with the storage arrays  106  via the network  104 . For example, at least a subset of the host devices  102  may be implemented as respective virtual machines of a compute services platform or other type of processing platform. The host devices  102  in such an arrangement illustratively provide compute services such as execution of one or more applications on behalf of each of one or more users associated with respective ones of the host devices  102 . 
     The term “user” herein is intended to be broadly construed so as to encompass numerous arrangements of human, hardware, software or firmware entities, as well as combinations of such entities. 
     Compute and/or storage services may be provided for users under a Platform-as-a-Service (PaaS) model, an Infrastructure-as-a-Service (IaaS) model and/or a Function-as-a-Service (FaaS) model, although it is to be appreciated that numerous other cloud infrastructure arrangements could be used. Also, illustrative embodiments can be implemented outside of the cloud infrastructure context, as in the case of a stand-alone computing and storage system implemented within a given enterprise. 
     The storage devices  108  of the storage array  106 - 1  may implement logical units (LUNs) configured to store objects for users associated with the host devices  102 . These objects can comprise files, blocks or other types of objects. The host devices  102  interact with the storage array  106 - 1  utilizing read and write commands as well as other types of commands that are transmitted over the network  104 . Such commands in some embodiments more particularly comprise Small Computer System Interface (SCSI) commands, although other types of commands can be used in other embodiments. A given  10  operation as that term is broadly used herein illustratively comprises one or more such commands. References herein to terms such as “input-output” and “IO” should be understood to refer to input and/or output. Thus, an  10  operation relates to at least one of input and output. 
     Also, the term “storage device” as used herein is intended to be broadly construed, so as to encompass, for example, a logical storage device such as a LUN or other logical storage volume. A logical storage device can be defined in the storage array  106 - 1  to include different portions of one or more physical storage devices. Storage devices  108  may therefore be viewed as comprising respective LUNs or other logical storage volumes. 
     In the information processing system  100  of  FIG. 1 , multiple ones of the storage arrays  106  may be part of a storage cluster, and the host devices  102  may submit  10  operations to be processed by the storage cluster. The storage cluster may comprise or provide an SDS system with one or more SDS storage pools. The storage controller  110  of storage array  106 - 1  is assumed to implement functionality for indicating drive bay status for drive bays of the drive bay enclosure  107  utilizing indicator circuitry  112 . The indicator circuitry  112  may comprise one or more lights (e.g., light-emitting diodes (LEDs)) or other visual indicators of the status of drive bays of the drive bay enclosure  107 . The indicator circuitry  112 , or at least a portion thereof such as one or more LEDs, are arranged within a housing of the drive bay enclosure  107  so as to be visible when activated behind turnover plates, filler plates and drive tray plates installed for the drive bays. The storage controllers  110  provide the functionality for indicating drive bay status for drive bays of the drive bay enclosure  107  utilizing a drive bay status determination module  114  and a drive bay status indicator signaling module  116 . The drive bay status determination module  114  is configured to determine status information for respective ones of the drive bays of the drive bay enclosure  107 . Such status information may include, but is not limited to, determining whether a given storage bay is ready for adding a storage device, whether an installed storage device matches storage system specifications (e.g., for use in one or more SDS storage pools), whether data errors have occurred, whether an installed storage device is a member of an SDS storage pool, whether operations for a SDS storage pool are ongoing for an installed storage device, whether an installed storage device is ready for removal or replacement, etc. The drive bay status indicator signaling module  116  is configured to control one or more status indicators (e.g., indicator circuitry  112 ) mounted on the housing of the drive bay enclosure  107  proximate openings for drive bays thereof based at least in part on the determined status information for such drive bays. 
     At least portions of the functionality of the drive bay status determination module  114  and the drive bay status indicator signaling module  116  may be implemented at least in part in the form of software that is stored in memory and executed by a processor. 
     Although shown as being implemented internal to the storage controllers  110  of the storage array  106 - 1 , it should be appreciated that the drive bay status determination module  114  and the drive bay status indicator signaling module  116  in other embodiments may be implemented at least in part external to the storage controllers  110 , including at least partially external to the storage array  106 - 1  such as within one or more of the host devices  102 , one or more other ones of the storage arrays  106 - 2  through  106 -M, one or more external servers, etc. 
     The host devices  102 , storage arrays  106  and storage controllers  110  implementing the drive bay status determination module  114  and the drive bay status indicator signaling module  116  in the  FIG. 1  embodiment are assumed to be implemented using at least one processing platform, with each processing platform comprising one or more processing devices each having a processor coupled to a memory. Such processing devices can illustratively include particular arrangements of compute, storage and network resources. For example, processing devices in some embodiments are implemented at least in part utilizing virtual resources such as virtual machines (VMs) or Linux containers (LXCs), or combinations of both as in an arrangement in which Docker containers or other types of LXCs are configured to run on VMs. 
     The host devices  102 , the storage arrays  106  and the storage controllers  110  implementing the drive bay status determination module  114  and the drive bay status indicator signaling module  116  may be implemented on respective distinct processing platforms, although numerous other arrangements are possible. For example, in some embodiments at least portions of one or more of the host devices  102 , the storage arrays  106  and the storage controllers  110  implementing the drive bay status determination module  114  and the drive bay status indicator signaling module  116  are implemented on the same processing platform. The storage controllers  110  implementing the drive bay status determination module  114  and the drive bay status indicator signaling module  116 , one or more of the storage arrays  106 , or combinations thereof, can therefore be implemented at least in part within at least one processing platform that implements at least a subset of the host devices  102 . 
     The network  104  may be implemented using multiple networks of different types to interconnect storage system components. For example, the network  104  may comprise a SAN that is a portion of a global computer network such as the Internet, although other types of networks can be part of the SAN, including a wide area network (WAN), a local area network (LAN), a satellite network, a telephone or cable network, a cellular network, a wireless network such as a WiFi or WiMAX network, or various portions or combinations of these and other types of networks. The network  104  in some embodiments therefore comprises combinations of multiple different types of networks each comprising processing devices configured to communicate using Internet Protocol (IP) or other related communication protocols. 
     As a more particular example, some embodiments may utilize one or more high-speed local networks in which associated processing devices communicate with one another utilizing Peripheral Component Interconnect express (PCIe) cards of those devices, and networking protocols such as InfiniBand, Gigabit Ethernet or Fibre Channel. Numerous alternative networking arrangements are possible in a given embodiment, as will be appreciated by those skilled in the art. 
     Although in some embodiments certain commands used by the host devices  102  to communicate with the storage arrays  106  illustratively comprise SCSI commands, other types of commands and command formats can be used in other embodiments. For example, some embodiments can implement IO operations utilizing command features and functionality associated with NVM Express (NVMe), as described in the NVMe Specification, Revision 1.3, May 2017, which is incorporated by reference herein. Other storage protocols of this type that may be utilized in illustrative embodiments disclosed herein include NVMe over Fabric, also referred to as NVMeoF, and NVMe over Transmission Control Protocol (TCP), also referred to as NVMe/TCP. 
     The storage array  106 - 1  in the present embodiment is assumed to comprise a persistent memory that is implemented using a flash memory or other type of non-volatile memory of the storage array  106 - 1 . More particular examples include NAND-based flash memory or other types of non-volatile memory such as resistive RAM, phase change memory, spin torque transfer magneto-resistive RAM (STT-MRAM) and Intel Optane™ devices based on 3D XPoint™ memory. The persistent memory is further assumed to be separate from the storage devices  108  of the storage array  106 - 1 , although in other embodiments the persistent memory may be implemented as a designated portion or portions of one or more of the storage devices  108 . For example, in some embodiments the storage devices  108  may comprise flash-based storage devices, as in embodiments involving all-flash storage arrays, or may be implemented in whole or in part using other types of non-volatile memory. 
     As mentioned above, communications between the host devices  102  and the storage arrays  106  may utilize PCIe connections or other types of connections implemented over one or more networks. For example, illustrative embodiments can use interfaces such as Internet SCSI (iSCSI), Serial Attached SCSI (SAS) and Serial ATA (SATA). Numerous other interfaces and associated communication protocols can be used in other embodiments. 
     The storage arrays  106  in some embodiments may be implemented as part of a cloud-based system. 
     The storage devices  108  of the storage array  106 - 1  can be implemented using solid state drives (SSDs). Such SSDs are implemented using non-volatile memory (NVM) devices such as flash memory. Other types of NVM devices that can be used to implement at least a portion of the storage devices  108  include non-volatile random access memory (NVRAM), phase-change RAM (PC-RAM) and magnetic RAM (MRAM). These and various combinations of multiple different types of NVM devices or other storage devices may also be used. For example, hard disk drives (HDDs) can be used in combination with or in place of SSDs or other types of NVM devices. Accordingly, numerous other types of electronic or magnetic media can be used in implementing at least a subset of the storage devices  108 . 
     The storage arrays  106  may additionally or alternatively be configured to implement multiple distinct storage tiers of a multi-tier storage system. By way of example, a given multi-tier storage system may comprise a fast tier or performance tier implemented using flash storage devices or other types of SSDs, and a capacity tier implemented using HDDs, possibly with one or more such tiers being server based. A wide variety of other types of storage devices and multi-tier storage systems can be used in other embodiments, as will be apparent to those skilled in the art. The particular storage devices used in a given storage tier may be varied depending on the particular needs of a given embodiment, and multiple distinct storage device types may be used within a single storage tier. As indicated previously, the term “storage device” as used herein is intended to be broadly construed, and so may encompass, for example, SSDs, HDDs, flash drives, hybrid drives or other types of storage products and devices, or portions thereof, and illustratively include logical storage devices such as LUNs. 
     As another example, the storage arrays  106  may be used to implement one or more storage nodes in a cluster storage system comprising a plurality of storage nodes interconnected by one or more networks. 
     It should therefore be apparent that the term “storage array” as used herein is intended to be broadly construed, and may encompass multiple distinct instances of a commercially-available storage array. 
     Other types of storage products that can be used in implementing a given storage system in illustrative embodiments include software-defined storage, cloud storage, object-based storage and scale-out storage. Combinations of multiple ones of these and other storage types can also be used in implementing a given storage system in an illustrative embodiment. 
     In some embodiments, a storage system comprises first and second storage arrays arranged in an active-active configuration. For example, such an arrangement can be used to ensure that data stored in one of the storage arrays is replicated to the other one of the storage arrays utilizing a synchronous replication process. Such data replication across the multiple storage arrays can be used to facilitate failure recovery in the system  100 . One of the storage arrays may therefore operate as a production storage array relative to the other storage array which operates as a backup or recovery storage array. 
     It is to be appreciated, however, that embodiments disclosed herein are not limited to active-active configurations or any other particular storage system arrangements. Accordingly, illustrative embodiments herein can be configured using a wide variety of other arrangements, including, by way of example, active-passive arrangements, active-active Asymmetric Logical Unit Access (ALUA) arrangements, and other types of ALUA arrangements. 
     These and other storage systems can be part of what is more generally referred to herein as a processing platform comprising one or more processing devices each comprising a processor coupled to a memory. A given such processing device may correspond to one or more virtual machines or other types of virtualization infrastructure such as Docker containers or other types of LXCs. As indicated above, communications between such elements of system  100  may take place over one or more networks. 
     The term “processing platform” as used herein is intended to be broadly construed so as to encompass, by way of illustration and without limitation, multiple sets of processing devices and one or more associated storage systems that are configured to communicate over one or more networks. For example, distributed implementations of the host devices  102  are possible, in which certain ones of the host devices  102  reside in one data center in a first geographic location while other ones of the host devices  102  reside in one or more other data centers in one or more other geographic locations that are potentially remote from the first geographic location. The storage arrays  106  may be implemented at least in part in the first geographic location, the second geographic location, and one or more other geographic locations. Thus, it is possible in some implementations of the system  100  for different ones of the host devices  102  and the storage arrays  106  to reside in different data centers. 
     Numerous other distributed implementations of the host devices  102  and the storage arrays  106  are possible. Accordingly, the host devices  102  and the storage arrays  106  can also be implemented in a distributed manner across multiple data centers. 
     Additional examples of processing platforms utilized to implement portions of the system  100  in illustrative embodiments will be described in more detail below in conjunction with  FIGS. 15 and 16 . 
     It is to be understood that the particular set of elements shown in  FIG. 1  for controlling status indicators (e.g., indicator circuitry  112 ) for drive bays of the drive bay enclosure  107  of the storage array  106 - 1  is presented by way of illustrative example only, and in other embodiments additional or alternative elements may be used. Thus, another embodiment may include additional or alternative systems, devices and other network entities, as well as different arrangements of modules and other components. 
     It is to be appreciated that these and other features of illustrative embodiments are presented by way of example only, and should not be construed as limiting in any way. 
     An exemplary process  200  for controlling status indicators for drive bays of a drive bay enclosure of a storage system will now be described in more detail with reference to the flow diagram of  FIG. 2 . It is to be understood that this particular process is only an example, and that additional or alternative processes for controlling status indicators for drive bays of a drive bay enclosure of a storage system may be used in other embodiments. 
     In this embodiment, the process  200  includes steps  202  and  204 . These steps are assumed to be performed by the storage controllers  110  utilizing the drive bay status determination module  114  and the drive bay status indicator signaling module  116 . The process begins with step  202 , determining status information for a given one of one or more drive bays in a housing of a drive bay enclosure of a storage system, the housing of the drive bay enclosure comprising one or more status indicators proximate the given drive bay. The one or more status indicators may be mounted to the housing, formed integrally with the housing, combinations thereof, etc. In step  204 , the one or more status indicators proximate the opening for the given drive bay are controlled based at least in part on the status information for the given drive bay determined in step  202 . 
     In some embodiments, the housing of the drive bay enclosure comprises a spindle housing one or more lights, and controlling the one or more status indicators in step  204  comprises selectively activating respective ones of the one or more lights housed in the spindle. The drive bay enclosure may further comprise a turnover plate rotatably mounted to the spindle proximate the opening for the given drive bay, with the turnover plate comprising at least one of the one or more status indicators. The at least one status indicator of the turnover plate is configured to passively illuminate in response to activation of one of the one or more lights housed in the spindle. The turnover plate may be configured to be rotated into a folded state when at least one of a filler plate and a drive tray plate is installed in the opening for the given drive bay, and to be rotated into an unfolded state covering at least a portion of the opening for the given drive bay when the filler plate and the drive tray plate are not installed in the opening for the given drive bay. The turnover plate may comprise a control circuit board configured for coupling to at least one of the one or more lights housed in the spindle. The drive bay enclosure may further comprise a filler plate installed in the opening for the given drive bay, where the filler plate comprises at least one of the one or more status indicators. The at least one status indicator of the filler plate is configured to passively illuminate in response to activation of one of the one or more lights housed in the spindle. The drive bay enclosure may further comprise a drive tray plate installed in the opening for the given drive bay, where the drive tray plate comprising at least one of the one or more status indicators. The at least one status indicator of the drive tray plate is configured to passively illuminate in response to activation of one of the one or more lights housed in the spindle. The drive tray plate may comprise first and second ones of the one or more status indicators. 
     In some embodiments, step  202  includes one or more of: determining whether the given drive bay is ready for adding a storage device, determining whether a storage device installed in the given drive bay is a member of a software-defined storage pool, determining whether a storage device installed in the given drive bay is performing one or more operations associated with a software-defined storage pool, determining whether a data error has occurred for a storage device installed in the given drive bay, determining whether a storage device installed in the given drive bay meets one or more specifications for a software-defined storage pool, and determining whether a storage device installed in the given drive bay is ready for at least one of removal and replacement. Step  204  may include selectively illuminating at least one indicator on at least one of a turnover plate and a filler plate covering the opening for the given drive bay responsive to determining that the given drive bay is reading for adding the storage device, selectively illuminating at least one indicator on a drive tray plate covering the opening for the given drive bay responsive to determining that the storage device installed in the given drive bay is a member of software-defined storage pool, selectively illuminating at least one indicator on a drive tray plate covering the opening for the given drive bay responsive to determining that the storage device installed in the given drive bay is performing the one or more operations associated with the software-defined storage pool, selectively illuminating at least one indicator on a drive tray plate covering the opening for the given drive bay responsive to determining that the data error has occurred for the storage device installed in the given drive bay, selectively illuminating at least one indicator on a drive tray plate covering the opening for the given drive bay responsive to determining that the storage device installed in the given dray meets the one or more specifications for the software-defined storage pool, and selectively illuminating at least one indicator on a drive tray plate covering the opening for the given drive bay responsive to determining that the storage device installed in the given drive bay is ready for at least one of removal and replacement. 
     Modern storage server systems may be equipped with a number of hot-swappable drive bays, on the front or rear panels, to achieve high-density storage. In data centers, SDS architectures leverage the internal storage resources on storage server systems to provide virtualized storage pools. Physical drive bay management is critical to a SDS system for scalability and serviceability. Conventional drive bay solutions, however, can only indicate limited hardware status for mounted drives. It is not easy for an IT infrastructure administrator to recognize a vacant slot, or to check the software status for each drive bay. This can give rise to incorrect manipulations and even data loss. 
     Illustrative embodiments provide transformable drive-indicating storage systems, which include one or more hot-swappable drive bays in a drive enclosure that is configured with indicator circuitry to indicate the software operation and running status for drives mounted in the hot-swappable drive bays. The transformable drive-indicating storage systems advantageously assist operators (e.g., end-users which add and remove storage drives from the hot-swappable drive bays of a drive enclosure) in interacting with storage management software for each of the hot-swappable drive bays in various working modes. With this approach, IT infrastructure administrators or other end-users can operate hot-swappable drive bays more easily, and the risk of maloperation will decrease significantly as well. 
     Generally, conventional hot-swappable drive bays are equipped with light-emitting diode (LED) indicators (e.g., a green LED and an amber LED) which are connected to a storage backplane through light pipes on the drive tray to show the status of device activity and health. However, these hardware statuses are only available for a mounted drive. Modern SDS systems require a greater variety of operational status information for both mounted and vacant hot-swappable drive bays. 
     The transformable drive-indicating storage system used in some embodiments includes a luminous spindle, with a turnover plate, filler plate and drive tray used in different working modes. If a storage drive is already installed in the drive bay, there are one or more software-controlled indicator lights (e.g., first and second multi-colored LEDs) on the luminous spindle of the drive tray. The software-controlled indicator lights may be turned on and off to indicate various status information for the installed storage drive. The traditional hardware indicator lights (e.g., green and amber LEDs) driven by a storage backplane are still retained at the other side of the hot-swappable drive bay. An additional software-controlled indicator light (e.g., a blue LED) is also provided on the filler plate for each vacant slot (e.g., on a newly-manufactured storage server system). If no filler plate is installed in a vacant drive bay slot, a short turnover plate with an active indicator (e.g., a blue LED) will emerge on the front of the drive bay slot. 
     The luminous spindle on the drive tray of the transformable drive-indicating storage system provides various features. The luminous spindle is installed inside the frame of a drive enclosure, and may be combined with a turnover plate (e.g., one for each drive bay slot that is configured to provide drive status as described herein). Thus, no extra panel room needs to be occupied to place the software-controlled indicators for the hot-swappable drive bays. If a drive or filler plate is installed in a hot-swappable drive bay, its associated turnover plate will be folded as an ordinary drive bay. If a drive and/or filler plate is removed from a hot-swappable drive bay, its associated turnover plate will turn up to play the same role of the indicator on the filler plate. A circuit board is used to control luminous rings on the luminous spindle and active indicators on the turnover plate. A set of spindle control boards is installed on the drive bay enclosure, which are able to communicate with a Baseboard Management Controller (BMC) on a server board via a serial bus connection, such as an Inter-Integrated Circuit (I 2 C) bus. Therefore, storage management software can control the software-controlled indicators (e.g., LEDs) on each drive bay via the in-band management channel on the BMC. Advantageously, an installed drive tray or filler plate is not required to have any electronic connections with the spindle control boards, as the software-controlled indicators will reflect light signals from the luminous rings on the luminous spindle as passive illuminants. 
       FIG. 3A  shows an example transformable drive-indicating storage system  300 , which includes a drive bay enclosure  301  with a set of hot-swappable drive bays. In the  FIG. 3A  example, there is one turnover plate  303  shown, as well as ten filler plates  305  and five drive tray plates  307 . The first five drive bays have drive tray plates  307  mounted therein (and thus the turnover plates  303  for such drive bays are in the folded state shown in  FIG. 4B , described below). The sixth drive bay has its turnover plate  303  in the unfolded state. The remaining ten drive bays have filler plates  305  mounted therein (and thus the turnover plates  303  for such drive bays are in the folded state shown in  FIG. 4B , described below).  FIG. 3B  shows a close-up view of the turnover plate  303 , which includes a center indicator  330 .  FIG. 3C  shows a close-up view of one of the filler plates  305 , which includes a top center indicator  350 .  FIG. 3D  shows a close-up view of one of the drive tray plates  307 , which includes a top left indicator  370  and a top right indicator  372 . The hot-swappable drive bays of the drive bay enclosure  301  of the transformable drive-indicating storage system  300  may thus operate in three working modes—a turnover plate  303  operating mode, a filler plate  305  operating mode, and drive tray plate  307  operating mode. 
     In the turnover plate  303  operating mode, a first indicator pattern is used to represent that an associated hot-swappable drive bay is ready for adding a drive and a second indicator pattern is used to represent that the associated hot-swappable drive bay is not ready for adding a drive. The first indicator pattern may be, for example, the center indicator  330  light blinking blue or some other designated color, while the second indicator pattern may include the center indicator  330  light being off, a steady light, a blinking light of a different color than that used in the first indicator pattern, etc. 
     In the filler plate  305  operating mode, a first indicator pattern is used to represent that an associated hot-swappable drive bay is ready for adding a drive, and a second indicator pattern is used to represent that the associated hot-swappable drive bay is not ready for adding a drive. The first and second indicator patterns in the filler plate  305  operating mode may be similar to the first and second indicator patterns used in the turnover plate  303  operating mode, though the indicator  350  is used rather than the center indicator  330 . As noted above, the indicator  350  may be a passive illuminant that reflects light from an LED on a luminous spindle. 
     For the drive tray plate  307  operating mode, a first indicator pattern is used to represent that a drive in the associated hot-swappable drive bay is configured, a second indicator pattern is used to represent that the drive in the associated hot-swappable drive bay is performing some designated operation (e.g., rebuilding data, performing a data migration, etc.), a third indicator pattern is used to represent that a data error has occurred on the drive in the associated hot-swappable drive bay, a fourth indicator pattern is used to represent that the installed drive in the associated hot-swappable drive bay is not “eligible” or otherwise does not match the specification of storage system requirements (e.g., for use in a designated SDS storage pool or some other application), a fifth indicator pattern is used to represent that the drive in the associated hot-swappable drive bay is ready for removal, and a sixth indicator pattern is used to represent that the associated hot-swappable drive bay is ready for replacing the current drive mounted therein. As mentioned above, the fourth indicator pattern may be used to represent that the installed drive in a given hot-swappable drive bay is not eligible, which is a concept utilized by various vendors (e.g., VMWare® vSAN, Microsoft® Storage Spaces Direct (S2D), NetApp®, etc.) to indicate that an installed drive does not match storage system requirements of an associated SDS storage pool or other application. 
     The first through sixth indicator patterns for the drive tray plate  307  operating mode may utilize various different combination of lighting the top left indicator  370  and the top right indicator  372 . For example, the first indicator pattern may include lighting the top left indicator  370  solid white or some other designated color, while keeping the top right indicator  372  off. The second indicator pattern may include blinking the top left indicator  370  white or some other designated color, while again keeping the top right indicator  372  off. The third indicator pattern may include lighting the top left indicator  370  solid amber, or some other designated color different than the color used in the first indicator pattern, while the top right indicator  372  is kept off. The fourth indicator pattern may include blinking the top left indicator  370  light amber, or some other color different than that used in the second indicator pattern, while simultaneously blinking the top right indicator  372  red or some other designated color. The fifth indicator pattern may include blinking the top right indicator  372  red or some other designated color, while keeping the top left indicator  370  off. The sixth indicator pattern may include alternating blinking of the top left indicator  370  and the top right indicator  372 , where the top left indicator  370  is blinking amber or some other designated color while the top right indicator  372  blinks red or some other designated color. 
     It should be noted that the above-described indicator patterns used for the turnover plate  303  operating mode, the filler plate  305  operating mode, and the drive tray plate  307  operating mode are presented by way of example only. Various other types of indicator patterns (e.g., blinking lights, steady lights, off lights, alternating blinking lights or colors, etc.) may be used as desired to represent different statuses of hot-swappable drive bays in a transformable drive-indicating storage system. Further, embodiments are not limited solely to indicating the statuses described above. Various additional drive bay statuses may be indicated through additional indicator patterns using indicator lights on the turnover plate  303 , filler plate  305  and drive tray plate  307 . 
       FIG. 4A  shows detail of a luminous spindle  400 , on which turnover plates  303 - 1 ,  303 - 2  and  303 - 3  (collectively, turnover plates  303 ) are mounted.  FIG. 4A  more particularly shows the turnover plate  303 - 2  in the center drive bay slot in the unfolded state, while the turnover plates  303 - 1  and  303 - 2  in the left and right drive bay slots are in the folded state. The luminous spindle  400  includes sets of luminous rings that are used to generate indicator patterns displayed on the turnover plates  303  (or on filler plates  305  or drive tray plates  307  when installed). In the  FIG. 4A  example, three sets of luminous rings are shown for three hot-swappable drive bay slots. Each set of luminous rings includes three lights (e.g., LEDs). Each of the sets of luminous rings includes a first light ( 401 - 1 ,  401 - 2  and  401 - 3 , collectively  401 ), a second light ( 402 - 1 ,  402 - 2  and  402 - 3 , collectively  402 ), and a third light ( 403 - 1 ,  403 - 2  and  403 - 3 , collectively  403 ). The lights  401  are used to control what is displayed in the top left indicators  370  of the drive tray plates  307 , the lights  402  are used to control what is displayed in the center indicators  330  of the turnover plates  303  and the indicators  350  of the filler plates  305 , and the lights  403  are used to control what is displayed in the top right indicators  372  of the drive tray plates  307 . 
       FIGS. 4B and 4C  illustrate the turnover plate  303  in folded and unfolded states.  FIG. 4B , for example, shows the turnover plate  303  folded up within the drive bay enclosure  301 .  FIG. 4B  also shows a circuit board  405  that is housed within the turnover plate  303 , and may be used for control of sets of lights of the luminous spindle  400  (e.g., for controlling the sets of lights  401 ,  402  and  403 ). The circuit board  405  is illustratively connected, via the luminous spindle  400  to a controller  410  (e.g., a BMC or other storage controller of a storage system such as one or more of the storage controllers  110  of the storage array  106 - 1  in system  100 ). The turnover plate  303  for a particular hot-swappable drive bay in some embodiments is in the folded state or position of  FIG. 4B  when a filler plate  305  is mounted to that hot-swappable drive bay, or when a drive and associated drive tray plate  307  is mounted to that hot-swappable drive bay.  FIG. 4C  shows the turnover plate  303  unfolded, with the center indicator  330  facing outwards from the drive enclosure  301 . 
       FIG. 5  shows a perspective view of a portion of a drive bay enclosure (e.g.,  301 ), including a drive tray plate  307  mounted in a first drive bay which has its associated turnover plate  303 - 1  in the folded state, a turnover plate  303 - 2  in the unfolded state in a second drive bay, and a filler plate  305  in a third drive bay which also has its associated turnover plate  303 - 3  in the folded state. The first and third drive bays have their turnover plates  303 - 1  and  303 - 2  in the folded position. The turnover plate  303 - 1  for the first drive bay is shown partially transparent, illustrating the circuit board  405  housed therein. Sets of lights  401 ,  402  and  403  are shown on a luminous spindle  400  for the first, second and third drive bays. In illustrative embodiments, the luminous spindle  400  may thus be embedded into the chassis frame of the drive bay enclosure  301 . Light sources are passed from the luminous spindle  400  to the indicators  370  and  372  of the drive tray plates  307  (e.g., through two short light pipes on the top of the drive tray). 
       FIG. 6  shows a front view of part of a drive enclosure (e.g.,  301 ) with three drive bays and associated turnover plates  303 - 1 ,  303 - 2  and  303 - 2  (collectively, turnover plates  303 ). First and second turnover plates  303 - 1  and  303 - 3  with associated center indicators  330 - 1  and  330 - 3  in the left and right drive bays are in the unfolded state or position, while the turnover plate  303 - 2  in the center drive bay is in the folded position. As shown, the turnover plate  303 - 1  is mounted to a luminous spindle (e.g.,  400 ) and has lights  401 - 1 ,  402 - 1  and  403 - 1 . The turnover plate  303 - 3  is also mounted to the luminous spindle and has lights  401 - 3 ,  402 - 3  and  403 - 3 . Lights for the turnover plate  303 - 2  in the folded state of the center drive bay are not shown for clarity of illustration. The turnover plate  303 - 1  is also shown partially transparent, illustrating the circuit board  405  contained therein which is coupled to the lights  401 - 1 ,  402 - 1  and  403 - 1 . 
     An example drive replacement workflow for hot-swapping a drive in a drive bay of the drive enclosure  301  of the transformable drive-indicating storage system  300  will now be described with respect to  FIGS. 7-14 . 
       FIG. 7  shows the transformable drive-indicating storage system  300 , and a drive bay of interest which currently has installed therein a filler plate  305  with its indicator  350  light off (e.g., not in a ready for adding a drive state). 
       FIG. 8  shows the filler plate  305  with its indicator  350  light blinking (e.g., lit  350 , off  350 ′, lit  350 ″, etc.) indicating that the associated drive bay is ready for adding a drive.  FIG. 8  also shows a view  800 , illustrating removal  801  of the filler plate  305  and insertion  903  of a drive into the drive bay. 
       FIG. 9  shows a ready for adding state that is indicated using turnover plate  303 , rather than filler plate  305 . The turnover plate  303  has its center indicator  330  light blinking (e.g., lit  330 , off  330 ′, lit  330 ″, etc.) indicating that the associated drive bay is ready for adding a drive.  FIG. 9  also shows a view  900 , illustrating insertion  901  of a drive into the drive bay (where insertion  901  of the drive will cause the turnover plate  303  to enter the folded state). 
       FIG. 10  shows a drive tray plate  307  indicating that a drive is ineligible (e.g., where the drive mounted in the drive bay does not meet storage requirements, such as requirements for a SDS storage pool). More particularly, the drive tray plate  307  has its top left indicator  370  and top right indicator  372  lights blinking simultaneously with one another (e.g., lit  370 ,  372 , off  370 ′,  372 ′, lit  370 ″,  372 ″).  FIG. 10  also shows views  1000 ,  1002  and  1004  illustrating removal  1001  of the mismatched drive and insertion  1003  of a new drive. 
       FIG. 11  shows a drive tray plate  307  indicating that the drive mounted therein is rebuilding data, performing data migration, or is otherwise subject to some application operation (e.g., for a SDS storage pool). More particularly, the drive tray  307  has its top left indicator  370  light blinking (e.g., lit  370 , off  370 ′, lit  370 ″) while the top right indicator  372  light remains off. 
       FIG. 12  shows the drive tray plate  307  with its top left indicator  370  light steady on and its top right indicator  372  light steady off. Depending on the color of the left indicator  370  light, this may represent different drive statuses. For example, if the left indicator  370  light is steady white, this may represent that the drive mounted therein is a member of a SDS storage pool. If the left indicator  370  light is steady amber, this may indicate a data error or software failure for the drive mounted therein. 
       FIG. 13  shows the drive tray plate  307  indicating that the drive mounted therein is ready for removal from the drive bay. More particularly, the drive tray plate  307  has its top right indicator  372  light blinking (e.g., lit  372 , off  372 ′, lit  372 ″) while the top left indicator  370  light remains off. 
       FIG. 14  shows the drive tray plate  307  indicating that the drive mounted therein is ready for replacement. More particularly, the drive tray plate  307  has its top light indicator  370  and top right indicator  372  lights blinking in turn (e.g.,  370  on and  372  off,  370 ′ off and  372 ′ on,  370 ″ on and  372 ″ off,  370 ′″ off and  372 ′″ on, etc.). 
     Using the turnover plates  303 , filler plates  305  and drive tray plates  307 , a transformable drive-indicating storage system  300  can indicate status information for both mounted and vacant drive bays in a drive enclosure  301 . The embedded and foldable mechanism of the turnover plate  303  advantageously does not require extra panel room. Further, the luminous spindle  400  (and associated lights  401 ,  402  and  403 ) provide passive illuminants on the front of the filler plates  305  and drive tray plates  307 , and also potentially the turnover plates  303 , thus not requiring electronic connections. The transformable drive-indicating storage system  300  may be used to help IT administrators and other users operate drive bays more easily, avoiding maloperation. Further, indicator patterns may be used to provide full-feature SDS status information with a high-density storage design. Further, even vacant drive bays (with or without filler plates  305 ) can show status information or operation tips using the turnover plates  303 . The indicators used in the transformable drive-indicating storage system  300  are also advantageously programmable, and may thus be tailored to the needs of specific use cases and controlled by various storage management software. The transformable drive-indicating storage system  300  may comprise any type of device that includes one or more hot-swappable drive bays, including but not limited to general-purpose servers, storage devices, storage chassis, etc. 
     It is to be appreciated that the particular advantages described above and elsewhere herein are associated with particular illustrative embodiments and need not be present in other embodiments. Also, the particular types of information processing system features and functionality as illustrated in the drawings and described above are exemplary only, and numerous other arrangements may be used in other embodiments. 
     Illustrative embodiments of processing platforms utilized to implement functionality for controlling status indicators for drive bays of a drive bay enclosure of a storage system will now be described in greater detail with reference to  FIGS. 15 and 16 . Although described in the context of system  100 , these platforms may also be used to implement at least portions of other information processing systems in other embodiments. 
       FIG. 15  shows an example processing platform comprising cloud infrastructure  1500 . The cloud infrastructure  1500  comprises a combination of physical and virtual processing resources that may be utilized to implement at least a portion of the information processing system  100  in  FIG. 1 . The cloud infrastructure  1500  comprises multiple virtual machines (VMs) and/or container sets  1502 - 1 ,  1502 - 2 , . . .  1502 -L implemented using virtualization infrastructure  1504 . The virtualization infrastructure  1504  runs on physical infrastructure  1505 , and illustratively comprises one or more hypervisors and/or operating system level virtualization infrastructure. The operating system level virtualization infrastructure illustratively comprises kernel control groups of a Linux operating system or other type of operating system. 
     The cloud infrastructure  1500  further comprises sets of applications  1510 - 1 ,  1510 - 2 , . . .  1510 -L running on respective ones of the VMs/container sets  1502 - 1 ,  1502 - 2 , . . .  1502 -L under the control of the virtualization infrastructure  1504 . The VMs/container sets  1502  may comprise respective VMs, respective sets of one or more containers, or respective sets of one or more containers running in VMs. 
     In some implementations of the  FIG. 15  embodiment, the VMs/container sets  1502  comprise respective VMs implemented using virtualization infrastructure  1504  that comprises at least one hypervisor. A hypervisor platform may be used to implement a hypervisor within the virtualization infrastructure  1504 , where the hypervisor platform has an associated virtual infrastructure management system. The underlying physical machines may comprise one or more distributed processing platforms that include one or more storage systems. 
     In other implementations of the  FIG. 15  embodiment, the VMs/container sets  1502  comprise respective containers implemented using virtualization infrastructure  1504  that provides operating system level virtualization functionality, such as support for Docker containers running on bare metal hosts, or Docker containers running on VMs. The containers are illustratively implemented using respective kernel control groups of the operating system. 
     As is apparent from the above, one or more of the processing modules or other components of system  100  may each run on a computer, server, storage device or other processing platform element. A given such element may be viewed as an example of what is more generally referred to herein as a “processing device.” The cloud infrastructure  1500  shown in  FIG. 15  may represent at least a portion of one processing platform. Another example of such a processing platform is processing platform  1600  shown in  FIG. 16 . 
     The processing platform  1600  in this embodiment comprises a portion of system  100  and includes a plurality of processing devices, denoted  1602 - 1 ,  1602 - 2 ,  1602 - 3 , . . .  1602 -K, which communicate with one another over a network  1604 . 
     The network  1604  may comprise any type of network, including by way of example a global computer network such as the Internet, a WAN, a LAN, a satellite network, a telephone or cable network, a cellular network, a wireless network such as a WiFi or WiMAX network, or various portions or combinations of these and other types of networks. 
     The processing device  1602 - 1  in the processing platform  1600  comprises a processor  1610  coupled to a memory  1612 . 
     The processor  1610  may comprise a microprocessor, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a central processing unit (CPU), a graphical processing unit (GPU), a tensor processing unit (TPU), a video processing unit (VPU) or other type of processing circuitry, as well as portions or combinations of such circuitry elements. 
     The memory  1612  may comprise random access memory (RAM), read-only memory (ROM), flash memory or other types of memory, in any combination. The memory  1612  and other memories disclosed herein should be viewed as illustrative examples of what are more generally referred to as “processor-readable storage media” storing executable program code of one or more software programs. 
     Articles of manufacture comprising such processor-readable storage media are considered illustrative embodiments. A given such article of manufacture may comprise, for example, a storage array, a storage disk or an integrated circuit containing RAM, ROM, flash memory or other electronic memory, or any of a wide variety of other types of computer program products. The term “article of manufacture” as used herein should be understood to exclude transitory, propagating signals. Numerous other types of computer program products comprising processor-readable storage media can be used. 
     Also included in the processing device  1602 - 1  is network interface circuitry  1614 , which is used to interface the processing device with the network  1604  and other system components, and may comprise conventional transceivers. 
     The other processing devices  1602  of the processing platform  1600  are assumed to be configured in a manner similar to that shown for processing device  1602 - 1  in the figure. 
     Again, the particular processing platform  1600  shown in the figure is presented by way of example only, and system  100  may include additional or alternative processing platforms, as well as numerous distinct processing platforms in any combination, with each such platform comprising one or more computers, servers, storage devices or other processing devices. 
     For example, other processing platforms used to implement illustrative embodiments can comprise converged infrastructure. 
     It should therefore be understood that in other embodiments different arrangements of additional or alternative elements may be used. At least a subset of these elements may be collectively implemented on a common processing platform, or each such element may be implemented on a separate processing platform. 
     As indicated previously, components of an information processing system as disclosed herein can be implemented at least in part in the form of one or more software programs stored in memory and executed by a processor of a processing device. For example, at least portions of the functionality for controlling status indicators for drive bays of a drive bay enclosure of a storage system as disclosed herein are illustratively implemented in the form of software running on one or more processing devices. 
     It should again be emphasized that the above-described embodiments are presented for purposes of illustration only. Many variations and other alternative embodiments may be used. For example, the disclosed techniques are applicable to a wide variety of other types of information processing systems, storage systems, status indicators, drive bay plates, etc. Also, the particular configurations of system and device elements and associated processing operations illustratively shown in the drawings can be varied in other embodiments. Moreover, the various assumptions made above in the course of describing the illustrative embodiments should also be viewed as exemplary rather than as requirements or limitations of the disclosure. Numerous other alternative embodiments within the scope of the appended claims will be readily apparent to those skilled in the art.