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Volume Concepts

Volume Concepts. Module 5. HP Restricted. Objectives. Describe basic RAID theory Describe the concepts of XP Parity Group and Free Space as they apply to drives with RAID theory

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Volume Concepts

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  1. Volume Concepts Module 5 HP Restricted

  2. Objectives • Describe basic RAID theory • Describe the concepts of XP Parity Group and Free Space as they apply to drives with RAID theory • Describe how Free Space is used in the XP array, including a discussion of emulation type and fixed volume creation • Describe the various XP array volume types including normal, custom, and expanded, including the process to create each type • Describe how XP volumes are made available for use by mapping a volume to a port • Describe the difference between an LDEV, a volume, and a LUN • Describe OPEN-V volume details and functionality, including benefits and implementation mechanisms HP Restricted

  3. A solution • RAID • Provides for highly available data despite a disk failure • Provides for online reconstruction of lost data • Costs space • Industry-standard redundancy algorithms HP Restricted

  4. From an array group of independent disks to an XP array Parity Group Protected data RAID control Unprotected data XP marketing array group XP array Parity Group (A group of disks) (A RAID group) XP array Parity Group (1 of 2) HP Restricted

  5. Protected data XP array Parity Group (A RAID group) XP array Parity Group (2 of 2) • RAID protected available space • Usable space • Free Space • How is Free Space created? HP Restricted

  6. The four steps to using Free Space • Define an emulation type for the Parity Group • Assign volume information • Map the volumes to a CHIP port • Connect the server HP Restricted

  7. Emulation types and normal volumes • Predefined (virtual) drive size • Defined for at the Parity Group level • Defining an emulation type creates a volume • Normal volumes are fixed in size • Open systems have OPEN-* emulation types HP Restricted

  8. OPEN-E Define emulation type OPEN-E OPEN-E OPEN-E Free space OPEN-E OPEN-E Free space Emulation type defined Parity Group Applying an emulation type • Assign an emulation type to the Parity Group HP Restricted

  9. Creating volumes • Exercise • Creating volumes from Free Space • Problem • A Parity Group with 32GB Free Space • An emulation type with a fixed size of 3.0GB • Questions • After setting the emulation type • How many normal volumes are created? • How much Free Space is left? HP Restricted

  10. Volume designation • The unique CU:LDEV number identifying the logical storage device • CU is control unit • LDEV is a logical device within a control unit • The CU and the LDEV number uniquely identify a virtual XP array disk or volume • Example • For volume 01:2a  CU=01, LDEV=2a HP Restricted

  11. XP array volumes • In the XP array a volume refers to the CU:LDEV number • The CU number is used by the XP internal data structures to manage virtual disks • One CU number can contain 256 LDEVs • The LDEV number is an arbitrary number from 0 – FF • Together, the CU and the LDEV number uniquely identify a virtual XP Array disk called a volume • Example • CU=1 and LDEV=2a, the volume = 1:2a HP Restricted

  12. OPEN-E OPEN-E Assign volume numbers OPEN-E 00:00 02:00 OPEN-E OPEN-E 01:00 OPEN-E 01:01 OPEN-E 02:01 Free Space FreeSpace Volume assignments Assigning volume information • After specifying an emulation type for a Parity Group, assign numbers to the OPEN-E volumes • The volume number uniquely identifies the virtual disk Emulation type defined HP Restricted

  13. Array configuration — addressing HP Restricted

  14. Solution: Banding (ZBR) Outer Band 12 Sectors Per Track Inner Band 6 Sectors Per Track HP Restricted

  15. Disk zones of a 72GB 15k rpm drive For sequential I/O loads a noticeable performance difference of about 20% between outer and inner tracks can be observed Comparing the performance of the ldevs across the drive surface it appears that there are three zones on the disk middle zone inner zone outer zone HP Restricted

  16. Data Placement on Drive • Outer tracks have a higher transfer rate than inner tracks • Preferably place sequential work areas on the outer tracks if performance needs to be optimized (e.g. Redo Logs) • In standard configurations the outer ldevs have the lower ldev numbers in the array group • The latency (affects random access) depends on the rotational speed and therefore is the same on the inner and outer tracks HP Restricted

  17. LUN mapping (mapping volumes) • Volumemapping • Mapping a volume to one or more CHIP ports • Alternate paths • How to uniquely identify the XP disk seen by server? HP Restricted

  18. Volume types • Normal volumes have a fixed size • Custom volumes have a smaller CVS • LUSE volumes are groupings of identical volumes to produce an extended volume HP Restricted

  19. OPEN-3 (2.4GB) LU Fixed size LU (normal volume) Small size LU (CVS volume) CVS(1.2GB) LU OPEN-3 (2.4GB) CVS(1.2GB) LUSE LU CVS(1.2GB) OPEN-3 (2.4GB) Large size LU (LUSE volume) CVS(1.2GB) Creating different volume types • Logical unit creation and sizes HP Restricted

  20. CVS • Smaller sized volumes • CVS are created from Free Space or from LDEVs that have been added to the free space • Used for XP command devices HP Restricted

  21. LUSE • Licensed functionality to create expanded volumes • Volumes must be similar (same CU, size, RAID type, and emulation) OPEN-9 *1 OPEN-9 * 1 Volume 0:01 OPEN-9 * 1 Volume 0:02 OPEN-9 * 3 OPEN-9 * 1 Volume 0:03 OPEN-9 * 1 Volume 0:04 HP Restricted

  22. LUSE functional description LUSE combines two or more LDEVs to function as one large LDEV (01:00) LUSE (01:00) (01:01) (01:03) (01:04) (01:05) HP Restricted

  23. OPEN-V overview • OPEN-V is a virtual emulation • A process and an emulation • Easily provides a custom volume size • Extension/combination of CVS and LUSE functionality • Volume sizes from 46.8MB to 2TB • Volume size is specified in either MB or cylinders orthe number of volumes to create HP Restricted

  24. LU FreeSpace Specify capacity LU LU Flexible size LU OPEN-V creation • LU creation with OPEN-V HP Restricted

  25. Basic specifications HP Restricted

  26. Function support HP Restricted

  27. Ways to create OPEN-V volumes • OPEN-V volumes can be created three ways • Specify volume size and number of volumes • Specify number of volumes • Specify the size of the volumes HP Restricted

  28. OPEN-V (40GB) Free Space OPEN-V (40GB) Initial volume creation method 1 • Specify the volume size and number of volumes Free Space ExampleSize = 40GB Number = 2 Parity Group (VDEV) HP Restricted

  29. OPEN-V OPEN-V OPEN-V OPEN-V Initial volume creation method 2 • Specify the number of volumes Free Space ExampleNumber = 4 Parity Group (VDEV) HP Restricted

  30. OPEN-V OPEN-V OPEN-V OPEN-V OPEN-V Free Space Initial volume creation method 3 • Specify the size of the volumes Free Space Example Size = 10GB Parity Group (VDEV) HP Restricted

  31. OPEN-V (40GB) OPEN-V (40GB) OPEN-V (40GB) OPEN-V (40GB) OPEN-V OPEN-V Free Space Free Space OPEN-V volume addition • Specify volume size and number of volumes ExampleSize = 3GB Number = 2 OPEN-V(3GB) Parity Group (VDEV) HP Restricted

  32. OPEN-V*2 (100GB) OPEN-V (50GB) Free Space OPEN-V (50GB) Free Space Internal mechanism (OPEN-V greater than 62GB) Create OPEN-Vvolume size = 100GB Internal CVS and LUSE procedures User view Free Space Create OPEN-VCVS LUSE Parity Group (VDEV) HP Restricted

  33. Learning check HP Restricted

  34. Lab activity HP Restricted

  35. HP Restricted

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