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Requirements for Dynamic Provisioning

The requirements for Dynamic Provisioning include license requirements, pool requirements, pool-VOL requirements, DP-VOL requirements, and page reservation requirements.

System requirements for provisioning

The system requirements for provisioning include basic hardware and licensing requirements as well as additional requirements for shared memory and cache management devices.

ItemRequirements and Restrictions
Storage system hardwareMust be configured and ready for use.
Parity groupsMust be configured and ready for use.
Hitachi Device Manager - Storage Navigator or CCIMust be configured and ready for use. For details and instructions, see the System Administrator Guide for your storage system.
License keys for the provisioning softwareMust be enabled. For details and instructions, see the System Administrator Guide for your storage system.
Required amount of shared memoryMust be installed in the storage system.
Required number of cache management devicesMust be available.
Applicable system option modes (SOMs)Must be enabled on your storage system before you begin operations. For information about SOMs, contact customer support.

Shared memory requirements

Additional shared memory is required when Dynamic Provisioning is used in conjunction with Dynamic Tiering, active flash, capacity saving (deduplication and compression), or Thin Image pools. The amount of additional shared memory needed depends on the size of the Dynamic Provisioning Thin Image and Dynamic Tiering pools.

Use the pool capacity or the V-VOL capacity within the capacity supported on the storage system. If the supported capacity is exceeded, it is recommended to install the shared memory function.

Shared memory is installed and removed by your service representative. For details about the installation and removal of shared memory, see the hardware reference guide for your storage system.

Caution Before shared memory is removed, all Dynamic Provisioning, Dynamic Tiering, and active flash pools must be deleted.

When Dynamic Provisioning, Dynamic Tiering, deduplication and compression, and Thin Image are used, the pool capacity and the V-VOL capacity that can be created are expanded according to the shared memory expansion status.

Shared memory function Pool/V-VOL capacity
Base Up to 4.4 PB
Extension 1 Up to 8.05 PB
Extension 2 Up to 12.5 PB
Extension 3 Up to 16.6 PB

License requirements

Before you use the capacity saving function, Dynamic Provisioning and dedupe and compression must be installed on the storage system.

Before you use Dynamic Tiering, Dynamic Provisioning and Dynamic Tiering must be installed on the storage system.

You need the Dynamic Tiering license to access the total capacity of the pool with the tier function enabled.

For Dynamic Provisioning, Dynamic Tiering, active flash, Dynamic Provisioning for Mainframe, Dynamic Tiering for Mainframe, and active flash for mainframe, the same license capacity as the DP-VOLs is required.

For active flash and active flash for mainframe, the same license capacity as the pool capacity is required.

Before you use active flash, the Dynamic Provisioning, and Dynamic Tiering software must be installed on the storage system. For this, you will need to purchase the Storage Virtualization Operating System (SVOS) license and the Dynamic Tiering and active flash license. You will need the Dynamic Tiering and active flash licenses for the total capacity of the pool with the tier function enabled.

If the DP-VOLs of Dynamic Provisioning or Dynamic Tiering are used for the primary volumes and secondary volumes of ShadowImage, TrueCopy, Universal Replicator, Volume Migration, global-active device, or Thin Image, you will need the ShadowImage, TrueCopy, Universal Replicator, Volume Migration, global-active device, and Thin Image licenses for the total pool capacity in use.

If you expand a Dynamic Provisioning pool that contains Thin Image pairs and snapshot data, the licensed capacity for both Dynamic Provisioning and Thin Image is required.

If you exceed the licensed capacity, you will be able to use the additional unlicensed capacity for 30 days. For more information about temporary license capacity, see the System Administrator Guide.

Cache management device requirements

Cache management devices manage the cache associated with volumes (LDEVs). Each volume (LDEV) requires at least one cache management device. An LDEV that is not a DP-VOL requires one cache management device. For an LDEV that is a DP-VOL, you need to calculate the number of cache management devices required.

The storage system can manage up to 65,280 cache management devices.

for more information, see Viewing cache management device resources.

Number of cache management devices required for DP-VOLs

A volume that is not a DP-VOL requires one cache management device. The number of cache management devices that a DP-VOL requires depends on the capacity of the V-VOL (capacity of the user area) and the maximum capacity of the cache management device.

This table explains the relationship between the pool volume attribute and the maximum capacity of the cache management device.

Pool volume attribute of V-VOL Maximum capacity of cache management device
MB

(GB)

Blocks Cylinders
Internal volume 711,768.75 MB

(695.08 GB)

1,457,702,400 blocks 837,760 cylinders
External volume 949,659.37 MB

(927.40 GB)

1,944,902,400 blocks 1,117,760 cylinders

Use this formula to calculate the number of cache management devices that a DP-VOL requires. In this formula, the user-specified capacity is the user area capacity of a V-VOL.

ceiling(user-specified-capacity / max-capacity-of-cache-management-device)

where

ceiling: The value enclosed in ceiling( ) must be rounded up to the nearest whole number.

NoteFor a DP-VOL with the deduplication or compression function enabled, use twice the number of the cache management devices calculated by this formula.

Viewing cache management device resources

  1. Click Actions.

  2. Select View Management Resource Usage window.

    The View Management Resource Usage window displays the current number of cache management devices in use and the maximum number of cache management devices.

Pool specifications and requirements

A pool is a set of volumes reserved for storing Dynamic Provisioning write data.

Items

Requirements

Pool capacity Calculate pool capacity using this formula:

Capacity of the pool (MB) = total-number-of-pages * 42 - 4200.

4200 in the formula is the management area size of the pool-VOL with System Area.

Total number of pages = Σ(floor(floor(pool-VOL number of blocks / 512) / 168)) for each pool-VOL.

floor( ): Truncates the value calculated from the formula in parentheses after the decimal point (that is, round down to nearest whole number).

However, the capacity of a pool is 3.9 GB to 4.0 GB, and the upper limit of total capacity of all pools is 16.6 PB on each storage system if shared memory is installed.

Because pools are limited to 1024 pool-VOLs, and pool-VOLs (LDEVs) are limited to 2.99TiB when created on internal storage (4 TiB when external), pools made from internal pool-VOLs are limited to 2.99PiB.

If you operate a pool without monitoring the free space, then ensure that the total DP-VOLs capacity remains smaller than the pool capacity.

Maximum number of pool-VOLs From 1 to 1,024 volumes (per pool).

A volume can be registered as a pool-VOL to one pool only.

Maximum number of pools Up to a total of 128 pools per storage system. The 128 pools include these pool types:
  • Dynamic Provisioning (including Dynamic Tiering)
  • Dynamic Provisioning for Mainframe (including Dynamic Tiering for Mainframe)
  • Thin Image

Pool IDs (0 to 127) are assigned as pool identifiers. The maximum number is 29 pools if a pool containing a DP-VOL with deduplication and compression enabled is included.

Increasing capacity You can increase pool capacity dynamically. Best practice is to add pool-VOLs to increase capacity by one or more parity groups.
Reducing capacity You can reduce pool capacity by removing pool-VOLs.
Deleting You can delete pools that are not associated with any DP-VOLs or with any Thin Image pairs or Thin Image snapshot data.
Subscription limit0 through 65534 (%).

You can set the subscription limit to Unlimited by leaving this field blank. Set the subscription limit to Unlimited only when you create the pool in either of these conditions:

  • The pool contains virtual volumes (V-VOLs) with accelerated compression enabled.
  • The pool contains parity groups with accelerated compression enabled.
Thresholds
  • Warning Threshold: You can set the value between 1% and 100%, in 1% increments. The default is 70%.
  • Depletion Threshold: You can set the value between the Warning Threshold and 100%, in 1% increments. The default is 80%.

If the pool used-capacity is equal to or greater than the warning threshold or the depletion threshold, a service information message (SIM) is issued by the storage system.

Thresholds cannot be defined for a pool with data direct mapping enabled.

Data allocation unit 42 MB

The 42-MB page corresponds to a 42-MB continuous area of the DP-VOL. Pages are allocated for the pool volumes only when data has been written to the area of the DP-VOL.

Tier

(Dynamic Tiering and active flash)

Defined based on the media type (see Drive type for a Dynamic Tiering tier, below). Maximum 3 tiers.
Maximum capacity of each tier

(Dynamic Tiering and active flash)

4.0 PB (Total capacity of the tiers must be within 4.0 PB

Pool-VOL requirements

Pool-VOLs make up a DP pool.

Item Requirements
Volume type Logical volume (LDEV)

While pool-VOLs can coexist with other volumes in the same parity group, for best performance:

  • Pool-VOLs for a pool should not share a parity group with other volumes.
  • Pool-VOLs should not be located on concatenated parity groups.

Pool-VOLs cannot be used for any other purpose. For instance, you cannot specify these volumes as pool-VOLs:

  • Volumes used by ShadowImage, Volume Migration, TrueCopy, global-active device, or Universal Replicator
  • Volumes already registered in Thin Image, Dynamic Provisioning, or Dynamic Tiering pools
  • Volumes used as Thin Image P-VOLs or S-VOLs
  • Volumes reserved by Data Retention Utility
  • Data Retention Utility volumes with a protect, read-only, or S-VOL disable attribute
  • LDEVs whose status is other than Normal, Correction Access, or Copying
  • Command devices
  • Quorum disks used by global-active device

This volume cannot be specified as a pool-VOL for Dynamic Tiering:

  • An external volume with the data direct mapping attribute enabled.

If the following conditions are met, pool-VOLs can be LDEVs created from the parity group with accelerated compression enabled:

  • All LDEVs created from one parity group must be applied to one pool.
  • The subscription limit of the pool must be Unlimited.
RAID level for a Dynamic Provisioning pool You can use one of these RAID levels:
  • RAID 1 (2D+2D, or concatenated 2 of 2D+2D)
  • RAID 5 (3D+1P, 4D+1P, 6D+1P, 7D+1P, concatenated 2 of 7D+1P, or concatenated 4 of 7D+1P)
  • RAID 6 (6D+2P, 12D+2P, or 14D+2P)

Pool-VOLs of RAID 5, RAID 6, RAID 1, and external volumes can coexist in the same pool. For pool-VOLs in the same pool:

  • It is best practice to use RAID 6 for pool-VOLs, especially for a pool where the recovery time of a pool failure due to a drive failure is not acceptable.
  • Pool-VOLs of different drive types with different RAID levels can coexist in the same pool. It is best practice to set one RAID level for pool-VOLs. If you register pool-VOLs with multiple RAID levels to the same pool, the I/O performance depends on the RAID levels of pool-VOLs to be registered. In that case, note the I/O performance of the drives.
RAID level for a Dynamic Tiering pool You can use one of these RAID levels:
  • RAID 1 (2D+2D, or concatenated 2 of 2D+2D)
  • RAID 5 (3D+1P, 4D+1P, 6D+1P, 7D+1P, concatenated 2 of 7D+1P, or concatenated 4 of 7D+1P)
  • RAID 6 (6D+2P, 12D+2P, or 14D+2P)

Pool-VOLs of RAID 5, RAID 6, RAID 1, and external volumes can coexist in the same pool. For pool-VOLs in the same pool:

  • It is best practice to use RAID 6 for pool-VOLs, especially for a pool where the recovery time of a pool failure due to a drive failure is not acceptable.
  • Pool-VOLs of different drive types with different RAID levels can coexist in the same pool. Set one RAID level for pool-VOLs. If you register pool-VOLs with multiple RAID levels to the same pool, the I/O performance depends on the RAID levels of pool-VOLs to be registered. In that case, note the I/O performance of the drives.
  • Because the speed of RAID 6 is slower than other RAID levels, tiers that use other RAID levels should not be placed under a tier that uses RAID 6.
Data drive type for a Dynamic Provisioning pool All drive types can coexist in the same pool with the following considerations.

Caution:

  • Pools should be built from pool-VOLs of the same capacity, type, and RAID level. If multiple pool-VOLs with different drive types are registered in the same pool, the I/O performance depends on the drive type of the pool-VOL to which the page is assigned. Therefore, if different drive types are registered in the same pool, ensure that the required I/O performance is not degraded by using less desirable drive types.
  • If multiple data drives coexist in the same pool, avoid using data drives that are different capacities.
Data drive type for a Dynamic Tiering or active flash pool Dynamic Tiering supports all drive types.

If active flash is used, SSD and FMD drives must be installed in advance.

If an LDEV created on an SCM drive is used as a pool-VOL, the LDEV can be combined with an LDEV whose drive type is SSD/NVMe or SSD, FMD/NVMe.

An LDEV created on an SCM drive cannot be added to an active flash pool.

If multiple data drives coexist in the same pool, it is best practice not to use data drives that are the same types and different capacity sizes.

Volume capacity Internal volume: From 8 GB to 2.9 TB

External volume: From 8 GB to 4 TB

External volume with the data direct mapping attribute: From 8 GB to 256 TB

LDEV format The LDEV format operation can be performed on pool-VOLs only when all of these conditions are satisfied:
  • There are no DP-VOLs defined for the pool, or all DP-VOLs defined for the pool are blocked.
  • The pool does not contain any Thin Image pairs or snapshot data.
Path definition You cannot specify a volume with a path definition as a pool-VOL.

Deduplication system data volume specifications and requirements

This table lists the requirements for the deduplication system data volume (fingerprint).

Item Description
Volume type DP-VOL (V-VOL).

When DP-VOLs using deduplication and compression are created, the deduplication system data volumes are automatically created.

Emulation type OPEN-V
Number per pool

24 deduplication system data volumes (fingerprint) are associated with a pool.

DRD-VOLs and deduplication system data volumes that belong to the same pool must belong to the same CLPR.

Volume capacity

1.7 TB

Cache management devices

1 deduplication system data volume (fingerprint) uses 1 cache management device.

Path definition Cannot be defined.
LDEV format Cannot be performed.

This table lists the requirements for the deduplication system data volume (data store).

Item Description
Volume type DP-VOL (V-VOL). When DP-VOLs using deduplication and compression are created, the deduplication system data volumes (data store) are automatically created.
Emulation type OPEN-V
Number per pool

24 deduplication system data volumes (data store) are associated with a pool.

Volume capacity

From 5.98TB to 42.7 TB

The DSD-VOL capacity has no impact on the DP-VOL capacity available to the host, which is described in the previous table.

The subsequent table describes the maximum capacity of deduplication system data volumes (data store) for a pool and a storage system.

The capacity size when the volumes are initially created is the same with the total capacity of pool volumes in a pool. When the pool operation starts, the total capacity of the 4 deduplication system data volumes (data store) automatically expands to the same size of the total pool volumes capacity. However, you can also manually expand capacities of these volumes.

Cache management devices

Number of cache management devices that are used for 1 deduplication system data volume is from 4 to 30.

Path definition Cannot be defined.
LDEV format Can be performed for LDEVs that are initialized of the duplicated data in a pool.

This table lists the maximum capacity of deduplication system data volumes (data store) for a pool and a storage system.

Added shared memories Maximum capacity of deduplication system data volumes (data store) for a pool (PB) Maximum capacity of deduplication system data volumes (data store) for a pool (PB)
Base Smaller capacity of the following:
  • 1.0
  • Total capacity of pool volumes in a pool
1.1
Extension 1 Smaller capacity of the following:
  • 1.0
  • Total capacity of pool volumes in a pool
2.0125
Extension 2 Smaller capacity of the following:
  • 1.0
  • Total capacity of pool volumes in a pool
3.125
Extension 3 Smaller capacity of the following:
  • 1.0
  • Total capacity of pool volumes in a pool
4.15

DP-VOL requirements

Items Requirements
Volume type DP-VOL (V-VOL)

The LDEV number is handled in the same way as for normal volumes.

Emulation type

OPEN-V

Maximum number of DP-VOLs Up to 63,232 per pool. Any number of available DP-VOLs can be associated with a pool.
  • For a pool with data direct mapping enabled: up to 1,023 per pool
  • For a pool with Deduplication enabled, 32,579 is the maximum number of DP-VOLs whose Capacity Saving is set to Compression or Deduplication and Compression.
  • For a pool with Deduplication disabled, 32,639 is the maximum number of DP-VOLs whose Capacity Saving is set to Compression.

Up to 63,232 volumes per system.

  • For a pool with data direct mapping enabled: up to 1,023 per pool
  • For a pool with deduplication enabled, 32,579 is the maximum number of DP-VOLs whose Capacity Saving is set to Compression or Deduplication and Compression.
  • For a pool with deduplication disabled, 32,639 is the maximum number of DP-VOLs whose Capacity Saving is set to Compression.

If external volumes and V-VOLs are used, the total number of external volumes and V-VOLs must be 63,232 or fewer.

Volume capacity

The volume capacity range per volume is from 46.87 MB to 256 TB. For DP-VOLs with data direct mapping enabled, the capacity range is from 8 GB to 256 TB.

  • TB: 0.01 to 256 (For DP-VOLs with data direct mapping enabled, the capacity range is from 0.01 TB to 256 TB)
  • GB: 0.04 to 262,144 (For DP-VOLs with data direct mapping enabled, the capacity range is from 8 GB to 262,144 GB.)
  • MB: 46.87 to 268,435,456 (For DP-VOLs with data direct mapping enabled, the capacity range is from 8,192 MB to 268,435,456 MB.)
  • Blocks: 96,000 to 549,755,813,888 (For DP-VOLs with data direct mapping enabled, the capacity range is from 16,777,216 blocks to 549,755,813,888 blocks.)

Total maximum volume capacity of 16.6 PB per storage system.

Path definition Available
LDEV format

Available. Quick Format is not available.

System option mode (SOM) 867 ON: When you format an LDEV on a DP-VOL, the capacity mapped to the DP-VOL is released to the pool as free space.

When you format a DP-VOL, the storage system releases the allocated page area in the DP-VOL. The quick format operation cannot be performed. If the LDEV format is applied to V-VOLs that are enabled for full allocation, the used capacity of the pool is not changed before the LDEV format is applied.

Caution:

For a DP-VOL with deduplication and compression enabled, a deduplication system data volume whose capacity saving status is Failed cannot be formatted.

Operating system and file system capacity

When initializing a DP-VOL, operating systems and file systems will consume some Dynamic Provisioning for Mainframe pool space. Some combinations initially take up little pool space, while other combinations take as much pool space as the virtual capacity of the DP-VOL.

This table shows the effects of some combinations of operating system and file system capacity. For more information, contact your service representative.

OS

File System

Metadata Writing

Pool Capacity Consumed

Windows Server 2003, Windows Server 2008, Windows Server 2012*

NTFS

Writes metadata to first block.

Effective reduction of pool capacity: Small (one page)

If file update is repeated, allocated capacity increases when files are updated (overwritten). Therefore, the effectiveness of reducing the pool capacity consumption decreases.

Linux, Linux

XFS

Writes metadata in Allocation Group Size intervals.

Effective reduction of pool capacity: Depends upon allocation group size.

The amount of pool space consumed will be approximately [DP-VOL Size] × [42 MB/Allocation Group Size].

Ext2

Ext3

Writes metadata in 128-MB increments.

Effective reduction of pool capacity: About 33% of the size of the DP-VOL.

The default block size for these file systems is 4 KB. This results in 33% of the DP-VOL acquiring DP pool pages. If the file system block size is changed to 2 KB or less than the DP-VOL Page consumption becomes 100%.

Solaris

UFS

Writes metadata in 52-MB increments.

No effective reduction of pool capacity.

Size of DP-VOL.

VxFS

Writes metadata to the first block.

Effective reduction of pool capacity: Small (one page).

AIX ®

JFS

Writes metadata in 8-MB increments.

No effective reduction of pool capacity.

Size of DP-VOL.

If you change the Allocation Group Size settings when you create the file system, the metadata can be written to a maximum interval of 64 MB. Approximately 65% of the pool is used at the higher group size setting.

JFS2

Writes metadata to the first block.

Effective reduction of pool capacity: Small (one page).

VxFS

Writes metadata to the first block.

Effective reduction of pool capacity: Small (one page).

HP-UX

JFS (VxFS)

Writes metadata to the first block.

Effective reduction of pool capacity: Small (one page).

HFS

Writes metadata in 10-MB increments.

No effective reduction of pool capacity.

Size of DP-VOL.

* In a Windows environment, both Normal Format and Quick Format are commonly used. In this environment, Quick Format consumes less thin provisioning pool capacities than Normal Format:

  • On Windows Server 2008 and Windows Server 2012, using Normal Format issues write commands to the overall volume (for example, overall "D" drive). When Write commands are issued, pages corresponding to the overall volume are allocated, so pool capacities corresponding to the ones of the overall volume are consumed. In this case, the thin provisioning advantage of reducing capacities is lost.
  • Quick Format issues write commands only to management information (for example, index information). Therefore, pages corresponding to the management information areas are allocated, but the capacities are smaller than the ones consumed by Normal Format.

V-VOL page reservation requirement

The V-VOL full allocation is performed in a range less than the depletion threshold size of the pool. If the capacity of V-VOLs is larger than the depletion threshold size, the full allocation operation is rejected.

CautionThe page reservation function is not supported by the following pools. To prevent data writing from being disabled due to pool overflow, you must monitor the free area of these pools frequently.
  • Pools that contain pool volumes belonging to a parity group with accelerated compression enabled
  • Pools with capacity saving enabled

Use the following formula to calculate the reserved page capacity for each pool. In the formula, the value enclosed in ceiling( ) must be rounded up to the nearest whole number.

Reserved capacity for each pool [block] =
ceiling(CV-capacity-of-V-VOL [block] / 86016) * 86016 + ceiling(CV-capacity-of-V-VOL [block] /
6442082304) * 4 * 86016 - used-capacity-of-V-VOL [block]