Abstract:
A high density storage enclosure houses first and second pluralities of hard disk drives (HDDs). The enclosure may be partitioned into a plurality of virtual enclosures, the first plurality of HDDs being associated with a first virtual enclosure and the second plurality of HDDs being associated with a second virtual enclosure. Configuration of the storage enclosure is performed by an SES processor in the storage enclosure accessing configuration parameters received from an external configuration unit coupled to the storage enclosure. The virtual enclosures may be configured as two (or more) independent virtual enclosures on two (or more) independent fabric loops. Power supplies and cooling blowers in the storage enclosure may also be partitioned and assigned to be managed by SES processors in the virtual enclosures.

Description:
RELATED APPLICATION DATA 
       [0001]    The present application is related to commonly-assigned and co-pending U.S. application Ser. No. 11/______ [IBM Docket #TUC920060006US1], entitled ESTABLISHING COMMUNICATIONS ACROSS VIRTUAL ENCLOSURE BOUNDARIES, 11/______ [IBM Docket # TUC920060008US1], entitled FLEXIBLE DISK STORAGE ENCLOSURE, and Ser. No. 11/______ [IBM Docket # TUC920060009US1], entitled RECONFIGURABLE FC-AL STORAGE LOOPS IN A DATA STORAGE SYSTEM, filed on the filing date hereof, which applications are incorporated herein by reference in their entireties. 
     
     TECHNICAL FIELD 
       [0002]    The present invention relates generally to data storage enclosures and; in particular, to enabling legacy control software., originally designed for low density storage enclosures; to be used with more densely populated storage enclosures. 
       BACKGROUND ART 
       [0003]      FIG. 1  is a block diagram of a low density storage enclosure  100 . The storage enclosure  100  includes a pair of redundant controller cards  110 A,  110 B, redundant power supplies  120 A,  1208  and sixteen disk drive modules (DDMs, also referred to as storage drives., hard disk drives or HDDs) indicated generally as  130 . The storage enclosure  100  also includes an enclosure midplane  140  and front and rear panels  150 A,  150 B. As illustrated in  FIG. 2 , each controller card  110 A,  110 B includes a switch  112 A,  112 B interconnected through the midplane to the storage drives  130 , and a SCSI enclosure services (SES) processor  114 A,  114 B which manages various enclosure-related processes, such as power and cooling. Due to the interconnection through the midplane between the SES processors  114 A,  114 B, in the event that one of the controller cards  110 A,  110 B fails, the other SES processor may take over.  FIG. 3  illustrates the interconnection of the power supplies  120 A,  120 B with the controller cards  110 A,  110 B and the DDMs  130  within the enclosure  100 . 
       SUMMARY OF THE INVENTION 
       [0004]    When additional DDMs, such as another sixteen, are installed in the enclosure  100  software, firmware and microcode designed for a sixteen-drive enclosure may not be able to accommodate the increased density. To control development effort and resources it is desirable to preserve the existing software, firmware and microcode base with minimal changes, while increasing the storage device density per unit of rack space. A single mechanical enclosure package that can accommodate multiple instances of enclosure designs that preserves the existing software, firmware, and microcode base interfaces is therefore highly desirable. 
         [0005]    The present invention provides a high density storage enclosure housing first and second pluralities of hard disk drives (HDDs). The enclosure may be partitioned into a plurality of virtual enclosures, the first plurality of HDDs being associated with a first virtual enclosure and the second plurality of HDDs being associated with a second virtual enclosure. Configuration of the storage enclosure is performed by an SES processor in the storage enclosure accessing configuration parameters received from an external configuration unit coupled to the storage enclosure. The virtual enclosures may be configured as two (or more) independent virtual enclosures on independent communication network fabric loops. Power supplies and cooling blowers in the storage enclosure may also be partitioned and assigned to be managed by SES processors in the virtual enclosures. A customer preferring the greater reliability of distributed storage may configure the storage enclosure as two (or more) virtual enclosures on independent communication network fabrics which may be coupled to separate control units. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a block diagram of a low density storage enclosure; 
           [0007]      FIG. 2  is a block diagram illustrating interconnections of the controller cards of the storage enclosure of  FIG. 1 ; 
           [0008]      FIG. 3  is a block diagram illustrating the power distribution within the storage enclosure of  FIG. 1 ; 
           [0009]      FIGS. 4A ,  4 B,  4 C illustrate front, rear and right side views, respectively, of a high density storage enclosure in which the present invention may be incorporated, 
           [0010]      FIG. 5A  is a block diagram of a flexible low- or high-density storage enclosure configurable as a single enclosure or as multiple virtual enclosures; 
           [0011]      FIG. 5B  is a block diagram of the flexible storage enclosure of  FIG. 5A  in a high-density configuration partitioned into two virtual enclosures on independent domains; and 
           [0012]      FIGS. 6A and 6B  illustrate a block diagram of the power distribution system of the high-density storage enclosure of  FIG. 5B . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0013]      FIGS. 4A ,  4 B,  4 C are representative front, rear and right side views, respectively, of a high density storage enclosure  400  in which thirty-two DDMs  430  have been installed, double the number in the enclosure of  FIG. 1 . In addition, the enclosure  400  includes two pairs of redundant controller cards  410 A and  410 B,  410 C and  410 D as well as a pairs of redundant power supplies  420 A,  420 B and blowers  440 A,  440 B. If desired, the enclosure  400  may be configured with a single instance of a storage enclosure (16 DDMs and a single pair of controller cards) by populating a single pair of controller cards in the enclosure and restricting the population of the DDMs to an appropriate placement within the enclosure. 
         [0014]    Implementing the present invention as illustrated in  FIG. 5A  a vendor may market a highly flexible storage enclosure, one which is configurable in a number of different ways. In one configuration, the enclosure  400  may be populated in a low density fashion, such as with up to sixteen drives  540  installed in drive connectors  522 A on a backplane  520  and two redundant controller cards  530 A,  530 B installed in controller card connectors  524 A,  524 B on the backplane  520  in a second configuration, the enclosure  400  may be populated in a high density fashions such as with up to an additional sixteen drives  590  installed in drive connectors  522 B and an additional pair of redundant controller cards  580 A,  580 B installed in card connectors  526 A,  526 B, configured as two virtual storage enclosures (as will be described with respect to  FIG. 5B ). In a third configuration, the enclosure  400  may be populated in a high density fashion, such as with thirty-two drives, but configured as a single storage enclosure. 
         [0015]      FIG. 58  is a block diagram of the storage enclosure  400  of  FIG. 5A  in a high-density configuration and partitioned into two virtual enclosures  500 ,  550 . As will be described below, each power supply  420 A,  420 B may each be associated with one of the virtual enclosures although they are shared by both virtual enclosures  500 ,  550  for redundancy purposes. The first virtual enclosure  500  includes sixteen DDMs  540  and a redundant pair of controller cards  530 A,  530 B. Both controller cards  530 A,  530 B include a switch  532 A,  532 B (see  FIGS. 6A ,  6 B), a SCSI enclosure services (SES) processor  534 A,  5348  and associated memory, such as nonvolatile storage (NVS)  536 A.  536 B. The backplane  520  may be partitioned into two (or more) virtual backplanes  502 ,  552  as part of the two virtual enclosures  500 ,  550 , respectively. One virtual backplane  502  interconnects the components of the first virtual enclosure  500  and an operator display panel  504  provides a display of the status of the enclosure  500 . A path  510 , such as a Fibre Channel/Arbitrated Loop (FC-AL) link, interconnects the two SES processors  534 A,  534 B with redundant external system control units (also known as system controllers)  600 . Redundant paths  512 A,  512 B, such as an inter-IC (I 2 C) bus, provide control paths from each SES processor  534 A,  5348  to each power supply  420 A,  420 B. Similarly, redundant paths  514 A,  514 B provide control paths from each SES processor  534 A,  534 B to a fan controller  422 A,  422 B in each power supply  420 A,  420 B. And, paths  516 A,  516 B interconnect each SES processor  534 A,  534 B with the first operator display panel  504 . 
         [0016]    Similarly, the second virtual enclosure  550  includes sixteen DDMs  590  and a redundant pair of controller cards  580 A,  580 B. Both controller cards  580 A,  580 B include a switch  582 A,  582 B (see  FIGS. 6A ,  6 B), an SES processor  584 A,  584 B and associated memory, such as NVS  586 A,  586 B. The second virtual backplane  552  interconnects the components of the second virtual enclosure  550  and an operator display panel  554  provides a display of the status of the enclosure  550 . A path  560 , such as an FC-AL link, interconnects the two SES processors  584 A,  584 B with the external system control units  600 . Redundant paths  562 A,  562 B, such as an I 2 C bus, provide control paths from each SES processor  584 A,  584 B to each power supply  420 A,  420 B Similarly, redundant paths  564 A,  564 B provide control paths from each SES processor  584 A,  584 B to a fan controller  422 A,  422 B in each power supply  420 A,  420 B. And, paths  566 A,  566 B interconnect each SES processor  584 A,  584 B with the second operator display panel  554 . 
         [0017]    Virtual enclosure midplanes  508 ,  558  interconnect the backplanes  502 ,  552  of the two virtual enclosures  500 ,  550 . Thus, the logical partitioning of the physical enclosures provides each of the two virtual enclosures  500 ,  550  with the disk fabric loop or network interconnections that they would have in the single enclosure design of  FIG. 1 . It will be appreciated that the physical enclosure may be configured as more than two virtual enclosures within the scope of the present invention. 
         [0018]    The controlling software, firmware or microcode is substantially the same with any of the three arrangements. The enclosure configuration may be performed when the enclosure  400  is installed or modified in a customer&#39;s facility. The SES processors  534 A,  534 B,  584 A,  584 B are coupled to a configuration unit  600  via the lines  510 ,  560  ( FIG. 5B ) One of the virtual enclosures, such as the first enclosure  500 , is designated as the master enclosure and one of the SES processors in the master enclosure, such as processor  534 A, is designated as the master processor (although the other SES processor  534 B may instead be designated as the master). Nonvolatile storage  536 A associated with the master processor  534 A stores an SES table  537  into which parameters are loaded from the configuration unit to define the enclosure configuration. The table  537  is then accessed by the master processor  534 A and enables and disables links within the physical enclosure  400  to configure the enclosure  400  with a single instance of a storage enclosure or with multiple virtual enclosures. 
         [0019]      FIGS. 6A and 6B  are a block diagram of the distribution of power from the power supplies  420 A,  420 B to the various components of the two virtual enclosures  500 ,  550 . As with the disk fabric network interconnections, the logical partitioning of the physical enclosures provided each of the two virtual enclosures  500 ,  550  with the power distribution and control functions that they would have in the single enclosure design of  FIG. 1 . According to the present invention, the first power supply  420 A and first blower  440 A ( FIG. 4B ) and the second power supply  420 B and second blower  4408  ( FIG. 4B ) each have redundant, independently controlled power outputs for the virtual enclosures  500  and  550 . When the system is configured as a single unit the outputs are coordinated as a single redundant power system. When configured as virtual enclosures, the outputs are controlled to allow an SES processor in each enclosure instance to manage the outputs as a separate redundant power system for each one. In this latter configuration, the SES processors  534 A,  534 B in the first virtual enclosure  500  may manage, separately or together, a first power/blower function (one output from each of the two power supplies  420 A,  420 B) for the first virtual enclosure  500  and the SES processors  584 A,  548 B in the second virtual enclosure  550  may manage, separately or together, a second power/blower function (the other output from each of the two power supplies  420 A,  420 B) for the second virtual enclosure  550 . The management of the power supply/blower function of the virtual enclosures  500 ,  550  may be configured in other ways, as well. 
         [0020]    It is important to note that while the present invention has been described in the context of a fully functioning data processing system, those of ordinary skill in the art will appreciate that the processes of the present invention are capable of being distributed in the form of a computer readable medium of instructions and a variety of forms and that the present invention applies regardless of the particular type of signal bearing media actually used to carry out the distribution. Examples of computer readable media include recordable-type media such as a floppy disk, a hard disk drive, a RAM, and COD-ROMs and transmission-type media such as digital and analog communication links. 
         [0021]    The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to best explain the principles of the invention, the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated. For example, certain components have been described as being coupled to a backplane and other components as being coupled to a mid-plane. However, such description is not intended to limit components to being coupled to either a backplane or to a mid-plane. Rather, either a backplane and a mid-plane may used and both may be generically labeled as a “connector plane.” Moreover, although described above with respect to methods and systems, the need in the art may also be met with a computer program product containing instructions for logically partitioning disk storage enclosures or a method for deploying computing infrastructure comprising integrating computer readable code into a computing system for logically partitioning disk storage enclosures.