COMPAQ Software Product Description ___________________________________________________________________ PRODUCT NAME: Compaq RAID Software SPD 46.49.07 for OpenVMS, Version 2.4A DESCRIPTION Compaq RAID Software for OpenVMS[R] is a software product that uses RAID technology to manage groups of disk drives as arrays. The prod- uct supports RAID Level 0 arrays (Disk striping) for enhanced I/O per- formance and RAID Level 5 arrays (Disk striping with parity) for en- hanced data availability on both VAX[R] and Alpha platforms. RAID Soft- ware also allows partitioning or segmentation of a RAID Array into mul- tiple virtual devices. RAID Software for OpenVMS Capabilities and Features RAID Software for OpenVMS manages groups of between 1 and 32 physi- cal disks (between 3 and 32 for RAID Level 5) as arrays. Applications use a virtual disk as if it were a physical disk. A total of 50 such arrays per VMScluster system are supported, in any mixture of RAID Level 0 and RAID Level 5. RAID virtual disks may be accessed directly from any member of a VM- Scluster system for which a valid license is in effect. (All VMSclus- ter systems may access virtual disks created using the Storage Con- current Use license QL-0MGAA-3B.) Virtual disks may not be MSCP[R] served. The disks in a RAID Software for OpenVMS array may be of different types, although disks of a single type are recommended for consistent per- formance and optimal use of storage capacity. October 1999 AE-Q1GDJ-TE RAID Software for OpenVMS virtual disks may not be used to boot the OpenVMS Operating System, nor may they serve as VMScluster quorum disks. They may, however, contain OpenVMS page and swap files. RAID Software for OpenVMS may be used in conjunction with OpenVMS Vol- ume Shadowing (Phase II only). OpenVMS shadow sets may be RAID Soft- ware for OpenVMS array members (RAID Level 0 only), however, virtual disks may not be members of OpenVMS shadow sets. A RAID Level 0 array whose members are shadow sets is a high perfor- mance, high data availability storage solution for most applications. Partitioning is the process of dividing a RAID array into one or more RAID virtual devices. The RAID Software allows you to specify how many partitions are to be used in a given RAID array and how large each par- tition should be. One or more partitions can be created on a single- member RAID Level 0 array or multiple-member RAID Level 0 or RAID Level 5 arrays. The Maximum number of partitions for any array is 64. Features Applicable to RAID Level 0 Arrays The usable capacity of RAID Level 0 array is approximately given by: Usable Capacity = N * 0.99 * CS Where N is the number of physical disks in the array. CS is the storage capacity of the smallest disk in the array. The purpose of RAID Level 0 technology is to provide I/O intensive ap- plications with greater I/O performance from a given I/O hardware con- figuration than would normally be achieved by using the disks as in- dividual volumes. This is also referred to as Disk Striping. Depend- ing on the application, enhanced I/O performance may be delivered as: o more I/O requests serviced per unit time due to probabilistic load balancing, or o higher data transfer rate due to concurrent transfer of data to or from more than one disk to satisfy a single request. 2 Features Applicable to RAID Level 5 Arrays The usable capacity of RAID Level 5 array is approximately given by: Usable Capacity = (N-1) * 0.99 * CS Where N is the number of physical disks in the array. CS is the capacity of the smallest disk in the array. RAID Software for OpenVMS protects against loss of data and loss of data accessibility due to the failure of any single disk in a RAID Level 5 array. If a disk in a RAID Level 5 array fails, RAID Software for OpenVMS provides continued service to applications by regenerating the failed disk's data using information from the array's remaining disks. (For full protection against loss of data availability due to single hardware failures, RAID Software for OpenVMS software can be used in conjunction with redundant hardware and supporting software through- out the system.) While a RAID Level 5 array is reduced by a failed disk, data can be read and written, but no redundancy is provided. A second disk fail- ure while an array is reduced prevents application access to the data stored on the array, and may result in data loss. RAID Software for OpenVMS reconstructs the contents of a failed disk if a replacement disk is assigned to it. Reconstruction does not in- terrupt application access to data on the array, although performance may be affected. Replacement disks may either be assigned to RAID Soft- ware for OpenVMS by the storage administrator (using a DCL command) or they may be placed in a spareset associated with one or more RAID Level 5 arrays. If a disk in a RAID Level 5 array with an associated spareset fails, RAID Software for OpenVMS automatically acquires a re- placement disk from the spareset and performs reconstruction without storage administrator intervention. Using RAID Software for OpenVMS 3 To use RAID Software for OpenVMS, the storage administrator first cre- ates an array using DCL functions supplied with the software. This de- stroys any data previously stored on the disks and creates the data structures required to manage the array. The member disks of a RAID Software for OpenVMS array are ODS-2 structured volumes, so OpenVMS mechanisms protect against inadvertent misuse of members for the life of the array. However, the virtual disk units created by RAID Soft- ware can be initialized as FILES-11 ODS2 or ODS5 or any other volume structure. Each virtual disk created by RAID Software for OpenVMS is a single man- agement entity. The storage administrator should use appropriate stor- age management procedures (e.g., backups) with virtual disks, which can be considerably larger than typical physical disks. Once a col- lection of physical disks is bound into an array, it is not possible to retrieve data directly from the array's individual member disks. Performance of RAID Software for OpenVMS The primary purpose of RAID for OpenVMS RAID Level 0 arrays is to en- hance application performance by improving I/O request processing and /or data transfer rate. RAID Level 0 technology normally implies a re- duction in data reliability. The storage administrator can improve data reliability by increasing backup frequency or using RAID Software for OpenVMS in conjunction with Volume Shadowing for OpenVMS. The primary purpose of RAID Software for OpenVMS RAID Level 5 arrays is to improve data reliability. It may provide the secondary benefit of improved performance (due to load balancing) for applications whose I/O workload consists largely of reading data. For applications with mostly write I/O workloads, RAID Software for OpenVMS RAID Level 5 ar- rays may provide lower I/O performance than conventional disks because it must update redundant information each time an application writes data. The storage administrator should understand application I/O charac- teristics and weigh the relative priorities of performance, equipment cost, and data reliability to determine whether RAID Software for Open- VMS is appropriate for use with a given application. 4 HARDWARE REQUIREMENTS RAID Software for OpenVMS is supported when used with the VAX and Al- pha processors and VMScluster systems supported by OpenVMS. See the Software Requirements section for the supported OpenVMS versions. RAID Software may be installed in a VMScluster configuration of any size supported by OpenVMS Software, but the RAID Software has been qual- ified to run on a maximum of 20 nodes within a single VMScluster con- figuration. RAID Software for OpenVMS requires a minimum of 1 (for RAID Level 0) or 3 (for RAID Level 5) and a maximum of 32 physical disks for each array. Up to 50 arrays may be created in a single VMScluster system. Disks, storage elements, (and the subsystem configurations that con- tain them) are supported by the OpenVMS Operating System Versions listed above through the following device drivers shown in Table 1. ___________________________________________________________________ Table_1:_Supporting_Device_Drivers_________________________________ Device Drivers___Description______________________________________________ DUDRIVER For Digital Storage Architecture (DSA) disks, including MSCP-served Disks. DKDRIVER For SCSI disks DRDRIVER For StorageWorks RAID Array 200 series controllers, also __________known_as_SWXCR___________________________________________ ___________________________________________________________________ Table_2:_Disk_Space_Requirements___________________________________ Disk_Space_______VAX-based_________Alpha-based_____________________ During instal- 3500 blocks 5000 blocks (2.44 megabytes) lation (1.70 megabytes) For permanent 2500 blocks 4000 blocks (1.85 megabytes) use______________(1.22_megabytes)__________________________________ 5 SOFTWARE REQUIREMENTS RAID Software for OpenVMS requires the OpenVMS VAX Operating System (Version 5.5-2, 6.2, 7.1 and 7.2) or OpenVMS Alpha (Versions 6.2, 7.1, 7.2 and 7.2-1) as a prerequisite. No other prerequisite software is required. Mixed-architecture VMScluster systems (i.e. containing both VAX and Alpha systems) are supported as long as all VMScluster members are run- ning compatible versions of the OpenVMS operating system supported by RAID Software. For a chart of the compatible versions of the operat- ing systems, refer to the VAXcluster Software for OpenVMS VAX Soft- ware Product Description (SPD 29.78.xx) and the VMScluster Software for OpenVMS Alpha Software Product Description (SPD 42.18.xx). RAID Software for OpenVMS is supported on OpenVMS 7.2 with the fol- lowing restrictions: SYSGEN Parameter MSCP_SERVE_ALL bit 3 must be set to prevent the serv- ing of Host Based Raidsets to other members of the cluster. Bit 3 en- ables the pre-V7.2 behavior of not serving Raidsets to other cluster members. In order to bind RAID arrays, all physical disks that comprise the RAID arrays must be accessible, (local or MSCP served), on all nodes in a VMScluster having the RAID software running. If RAID Level 0 arrays with OpenVMS shadow sets as members are required, a valid OpenVMS Volume Shadowing license must be in effect on every VMScluster node running the RAID Software. Shadow sets may not be used as members of RAID Level 5 arrays. The Product is Year 2000 Ready Year 2000 Ready is defined: "Year 2000 Ready" products are defined by Compaq as products capable of accurately processing, providing, and /or receiving date data from, into and between the twentieth and the twenty-first centuries, and the years 1999 and 2000, including leap 6 year calculations, when used in accordance with the associated prod- uct documentation and provided that all hardware, firmware and soft- ware used in combination with such products properly exchange accu- rate date data with the products. For additional information visit Compaq's Year 2000 Ready products' web site located at: http://www.compaq.com/year2000/ DISTRIBUTION MEDIA TK50 Streaming Tape 1600 bpi Magtape This layered product is also available as part of the OpenVMS Consol- idated Software Distribution on CD-ROM for VAX (QA-VWJ8A-A8) and on the Digital CD-ROM Software Library for OpenVMS Alpha (QA-03XAA-H8). ORDERING INFORMATION Three licensing options are available: RAID Array Access License: VAX: QL-0MHA*-AA Alpha: QL-2YFA*-AA This license option provides the purchaser with the right to use the RAID Software for OpenVMS on a single VAX or Alpha system to create and use up to the supported number (50) of RAID arrays. One RAID Ar- ray Access License is required for each VAX or Alpha system in a VM- Scluster system on which RAID Software for OpenVMS is to execute. Storage Concurrent Use License: QL-0MGAA-3B This license option provides the purchaser with the right to include a single disk, storage element, or shadow set in an array. One Stor- age Concurrent Use License is required for each disk, storage element, or shadow set to be included in a RAID Software for OpenVMS array. Once 7 an array is created, it may be accessed by any VMScluster VAX or Al- pha system. For purposes of the Storage Concurrent Use License, the measure of use is equal to a single disk, storage element, or shadow set to be in- cluded in an array, no matter how many VMScluster CPUs have access to that array. Each shadow set used as a member of a RAID Level 0 array requires a single Concurrent Use License, regardless of the number of physical disks in the shadow set. Disks, storage elements, and shadow sets that are members of spare- sets do not require Storage Concurrent Use Licenses. Upgrade license from POLYCENTER Striping for OpenVMS VAX QL-3AXA*-AA This option is for POLYCENTER Striping for OpenVMS VAX licensed cus- tomers who want to upgrade to the full functionality of RAID Software on OpenVMS VAX, which includes Striping, Striping with Parity, and Par- titioning. A migration option also exists which provides just the Striping ca- pability. Refer to the software licensing section for more informa- tion. Media: VAX: QA-0MGAA-H5 VAX: QA-0MGAA-HM Documentation: VAX: QA-0MGAA-GZ Alpha: QA-0MGAA-GZ Software Product Services: Array Access (VAX): QT-0MHA*-** Array Access (Alpha): QT-2YFA*-** Storage: QT-0MGA*-** 8 SOFTWARE LICENSING This software is furnished only under a license. RAID Software V2.4, and continuing with future releases, the right to use the RAID Level 0 function of the RAID Software is included in the license for POLYCENTER Striping for OpenVMS VAX. This applies to Open- VMS VAX installations only as POLYCENTER Striping operates solely on that platform. For more information about Digital's licensing terms and conditions, contact your local Digital office. License Management Facility Support RAID Software for OpenVMS software uses the OpenVMS License Manage- ment Facility. License Units for the RAID Software for OpenVMS RAID Array Access Li- cense are allocated on a CPU-capacity basis. License Units for the RAID Software for OpenVMS Storage Concurrent Use License are independent of CPU capacity. One Storage Concurrent Use License is required for each disk, storage element, or shadow set in- cluded in an array, no matter how many VMScluster CPUs have access to the array. For more information on the License Management Facility, refer to the OpenVMS Operating System Software Product Description (SPD 25.01.xx) or the OpenVMS Operating System documentation. SOFTWARE PRODUCT SERVICES A variety of software product service options are available from Dig- ital. For more information, contact your local Digital office. 9 SOFTWARE WARRANTY This software is provided by Compaq with a 90 day conformance warranty in accordance with the Compaq warranty terms applicable to the license purchase. [TM]The Digital logo, DEC, Digital, MSCP, OpenVMS, TK, VAX, and VMScluster are trademarks of Digital Equipment Corporation. All other trademarks and registered trademarks are the property of their respective holders. © 1999 Compaq. All rights reserved. 10