mkvdisk

Parameters

-mdiskgrp mdisk_group_id_list | mdisk_group_name_list

(Required) Specifies one or more storage pools to use when you are creating this volume. If you are creating multiple copies, you must specify one storage pool per copy. The primary copy is allocated from the first storage pool in the list.

-udid vdisk_udid

(Optional) Specifies the unit number udid for the disk. The udid is an identifier that is required to support OpenVMS hosts; no other systems use this parameter. Valid options are a decimal number 0 - 32 767, or a hexadecimal number 0 - 0x7FFF. A hexadecimal number must be preceded by 0x (for example, 0x1234).

-vtype seq | striped | image

(Optional) Specifies the virtualization type. When you create sequential or image mode volumes, you must also specify the -mdisk parameter. You cannot use -vtype seq or -vtype image in a data reduction pool. The default virtualization type is striped.

-iogrp io_group_id | io_group_name

(Optional) Specifies the I/O group (node pair) with which to associate this volume. If you specify -node, you must also specify -iogrp.

Remember:

• Create the first compressed volume copy for an I/O group to activate compression.
• You cannot create or move a volume copy that is compressed to an I/O group that contains at least one node that does not support compressed volumes. You must select another I/O group to move the volume copy to (but it does not affect moving to the recovery I/O group).

-accessiogrp iogroup_id_list | iogroup_name_list

(Optional) Specifies the members of the volume I/O group access set. If this option is not specified, only the caching I/O group is added to the volume I/O group access set. If this option is specified, then the -iogrp option must also be specified and the I/O group access set must include the I/O group that is specified by the -iogrp parameter.

-size disk_size

(Required for sequential or striped volume creation) (Optional for image volume creation) Specifies the capacity of the volume, which is used with the value of the unit. All capacities, including changes, must be in multiples of 512 bytes. An error occurs if you specify a capacity that is not a multiple of 512. It can only happen when byte units (-b) are used. However, an entire extent is reserved even if it is only partially used. The default capacity is in MB. You can specify a capacity of 0. Specify the size in bytes in multiples of logical block address (LBA) sizes.

Note: If you do not specify the -size parameter when you create an image mode disk, the entire MDisk capacity is used.

-fmtdisk

(Optional) Specifies that the volume be formatted. This parameter is no longer required for any volumes.

This parameter is not required when you create standard-provisioned volumes. The format operation is automatically applied to standard-provisioned volumes unless you specify -nofmtdisk parameter. The format operation sets the extents that make up this volume to all zeros after it is created. This process takes place in the background concurrently with host I/O operations on the new volume.

Remember: Formatting is on by default for single copy, standard-provisioned, and non-image mode volumes. You cannot format an image mode volume.

The format operation completes asynchronously. You can query the status by using the lsvdiskprogress command. You cannot specify this parameter with the -vtype image parameter.

This parameter is not required when you create thin-provisioned volumes. Thin-provisioned volumes return zeros for extents that are not written to. No format operation is required. This parameter also synchronizes mirrored copies by default.

-nofmtdisk

(Optional) Specifies that formatting be turned off for the new volume.

Remember: Formatting is on by default for single copy, standard-provisioned, and non-image mode volumes, and you can specify this parameter to turn it off.

-rsize disk_size | disk_size_percentage% | auto

(Optional) Defines how much physical space is initially allocated to the thin-provisioned or compressed volume. This parameter makes the volume thin-provisioned; otherwise, the volume is standard-provisioned. Specify the disk_size | disk_size_percentage value by using an integer, or an integer immediately followed by the percent character (%). Specify the units for a disk_size integer by using the -unit parameter; the default is MB. The -rsize value can be greater than, equal to, or less than the size of the volume. The auto option creates a volume copy that uses the entire size of the MDisk.

If you specify the -rsize auto option, you must also specify the -vtype image option. If you specify -import you must specify -rsize.

If the volume is in a data reduction storage pool, the value of the -rsize parameter will be ignored in mkvdisk. Only its presence or absence is used to determine whether the disk is a data reduction volume copy or a thick volume copy.

-warning disk_size | disk_size_percentage%

(Optional) Requires that the -rsize parameter also be specified. Specifies a threshold at which a warning error log is generated for volume copies. A warning is generated when the used disk capacity on the thin-provisioned copy first exceeds the specified threshold.

Note: You cannot specify this parameter for thin-provisioned or compressed volumes that are in data reduction pools.

You can specify a disk_size integer, which defaults to MBs unless the -unit parameter is specified. Or you can specify a disk_size%, which is a percentage of the volume size.

Important: If -autoexpand is:

1. Enabled, the default value for -warning is 80% of the volume capacity.
2. Not enabled, the default value for -warning is 80% of the real capacity.

To disable warnings, specify 0.

-autoexpand

(Optional) Specifies that thin-provisioned copies automatically expand their real capacities by allocating new extents from their storage pool. Requires that the -rsize parameter also be specified. If the -autoexpand parameter is specified, the -rsize parameter specifies a capacity that is reserved by the copy. It protects the copy from going offline when its storage pool runs out of space by having the storage pool to consume this reserved space first.

The parameter has no immediate effect on image mode copies. However, if the image mode copy is later migrated to managed mode, the copy is then automatically expanded.

-grainsize 32 | 64 | 128 | 256

(Optional) Sets the grain size (KB) for a thin-provisioned volume. This parameter also requires that the -rsize parameter be specified. If you are using the thin-provisioned volume in a FlashCopy® map, use the same grain size as the map grain size for best performance. If you are using the thin-provisioned volume directly with a host system, use a small grain size. The grain size value must be 32, 64, 128, or 256 KB. The default is 256 KB.

If the volume to be created is a thin-provisioned volume in a data reduction storage pool, the -grainsize parameter cannot be used. This type of volume will be created with a grain size of 8 KB.

-deduplicated

(Optional) Creates a deduplicated volume. If you specify -deduplicated, you must also specify -rsize because it applies only to thin-provisioned or compressed volumes.

Note: Data deduplication works only with data reduction storage pools. You can only create deduplicated volumes and volume copies in an I/O group if there are no compressed volumes or volume copies in regular storage pools.

-compressed

(Optional) Enables compression for the volume. This parameter must be specified with -rsize and cannot be specified with -grainsize.

-import

(Optional) Imports a thin-provisioned volume from the MDisk. If you specify -import you must also specify -rsize.

-copies num_copies 

(Optional) Specifies the number of copies to create. The num_copies value can be 1 or 2. Setting the value to 2 creates a mirrored volume. The default value is 1.

-createsync

(Optional) Creates copies in sync. Use this parameter if you have already formatted the MDisks, or when read stability to unwritten areas of the volume is not required.

-syncrate syncrate 

(Optional) Specifies the copy synchronization rate. A value of zero (0) prevents synchronization. The default value is 50. See Table 2 for the supported -syncrate values and their corresponding rates. Use this parameter to alter the rate at which the standard-provisioned volume or mirrored volume format before synchronization.

-mirrorwritepriority latency | redundancy

(Optional) Specifies how to configure the mirror write algorithm priority. If not specified, the default value is latency.

1. Choosing latency means a copy that is slow to respond to a write input/output (I/O) becomes unsynchronized, and the write I/O completes if the other copy successfully writes the data.
2. Choosing redundancy means a copy that is slow to respond to a write I/O synchronizes completion of the write I/O with the completion of the slower I/O to maintain synchronization.

-mdisk mdisk_id_list | mdisk_name_list

(Optional) Specifies one or more managed disks. For sequential and image mode volumes, the number of MDisks must match the number of copies. For sequential mode volumes, each MDisk must belong to the specified storage pool. For striped volumes, you cannot specify the -mdisk parameter if the -copies value is greater than 1.

When you create a single copy striped volume, you can specify a list of MDisks to stripe across.

You must use this parameter to specify an MDisk that has a mode of unmanaged.

-node node_id | node_name

(Optional) Specifies the preferred node ID or the name for I/O operations to this volume. You can use the -node parameter to specify the preferred access node. If you specify -node, you must also specify -iogrp.

Note: This parameter is evaluated by multipath device drivers. The system chooses a default if you do not supply this parameter.

-unit b | kb | mb | gb | tb | pb

(Optional) Specifies the data units to use along with the capacity that is specified by the -size and -rsize parameters. The default unit type is MB.

-name new_name_arg

(Optional) Specifies a name to assign to the new volume.

-cache readwrite | readonly | none

(Optional) Specifies the caching options for the volume. Valid entries are:

• readwrite enables the cache for the volume.
• readonly disables write caching while allowing read caching for a volume.
• none disables the cache mode for the volume.

The default is readwrite.

-tier tier0_flash | tier1_flash | tier_enterprise | tier_nearline | tier_scm

(Optional) Specifies the MDisk tier when an image mode copy is added. This parameter is valid only when -vtype is image.

tier0_flash

Specifies a tier0_flash hard disk drive or an external MDisk for the newly discovered or external volume.

tier1_flash

Specifies an tier1_flash (or flash drive) hard disk drive or an external MDisk for the newly discovered or external volume.

tier_enterprise

Specifies a tier_enterprise hard disk drive or an external MDisk for the newly discovered or external volume.

tier_nearline

Specifies a tier_nearline hard disk drive or an external MDisk for the newly discovered or external volume.

tier_scm

Specifies a tier_scm hard disk drive or an external MDisk for the newly discovered or external volume.

ssd

Specifies an SSD (or flash drive) hard disk drive or an external MDisk for the newly discovered or external volume.

nearline

Specifies a nearline hard disk drive or an external MDisk for the newly discovered or external volume.

enterprise

Specifies an enterprise hard disk drive or an external MDisk for the newly discovered or external volume.

Note: This action applies to both copies if you are creating a mirrored volume with two image mode copies by using this command.

-easytier on | off

Determines whether the IBM® Easy Tier® function is allowed to move extents for this volume.

Note: The -easytier parameter must be followed by either on or off:

• If set to on, then Easy Tier functions are active.
• If set to off, then Easy Tier functions are inactive.

If the Easy Tier feature is enabled, and if a volume copy is striped and not being migrated, the following table applies.

Table 1. Easy Tier settings for storage pools and volumes

Storage pool Easy Tier setting	Number of tiers in the storage pool	Volume copy Easy Tier setting	Volume copy Easy Tier status
Off	One	Off	inactive (see note 1)
Off	One	On	inactive (see note 1)
Off	Two	Off	inactive (see note 1)
Off	Two	On	inactive (see note 1)
Measure	One	Off	measured (see note 2)
Measure	One	On	measured (see note 2)
Measure	Two	Off	measured (see note 2)
Measure	Two	On	measured (see note 2)
Auto	One	Off	measured (see note 2)
Auto	One	On	balanced (see note 3)
Auto	Two	Off	measured (see note 2)
Auto	Two	On	active (see note 4)
On	One	Off	measured (see note 2)
On	One	On	balanced (see note 3)
On	Two	Off	measured (see note 2)
On	Two	On	active (see note 4)
Notes: When the volume copy status is inactive, no Easy Tier functions are enabled for that volume copy. When the volume copy status is measured, the Easy Tier function collects usage statistics for the volume but automatic data placement is not active. When the volume copy status is balanced, the Easy Tier function enables performance-based pool balancing for that volume copy. When the volume copy status is active, the Easy Tier function operates in automatic data placement mode for that volume.

If the volume copy is in image or sequential mode or is being migrated, the volume copy Easy Tier status is measured instead of active.

The default Easy Tier setting for a storage pool is auto, and the default Easy Tier setting for a volume copy is on. It means that Easy Tier functions except pool performance balancing are disabled for storage pools with a single tier, and that automatic data placement mode is enabled for all striped volume copies in a storage pool with two or more tiers.