Use the mkvdisk command to create sequential, striped, or image mode
volume objects. When they are mapped to a host object, these objects are seen as disk drives with
which the host can run I/O operations. Note that the first syntax diagrams below is for striped or
sequential volumes and the second syntax diagram is for image mode volumes. Use the
mkvolume command for a simplified way of creating high availability volumes.This includes hyperswap topology. Use the mkimagevolume
command for a simplified way of creating an image mode volume, importing existing data from a
managed disk.
Note: The first syntax
diagram depicts the creation of a sequential or striped mode
volume. The second syntax diagram depicts the creation of an image mode
volume.
Syntax
mkvdisk -mdiskgrp { mdisk_group_id_list | mdisk_group_name_list } [ -udid vdisk_udid ] [ -vtype { striped | seq } ] [ -iogrp { io_group_id | io_group_name } ] [ -size disk_size ] [ -accessiogrp { iogrp_id_list | iogrp_name_list } ] [ -fmtdisk ] [ -nofmtdisk ] [ -rsize { disk_size | disk_size_percentage% | auto } [ -warning { disk_size | disk_size_percentage% } ] [ -autoexpand ] [ -grainsize { 32 | 64 | 128 | 256 } ] ] [ -compressed ] [ -copies num_copies [ -createsync ] [ -syncrate syncrate ] ] [ -mirrorwritepriority { latency | redundancy } ] [ -mdisk { mdisk_id_list | mdisk_name_list } ] [ -node { node_name | node_id } ] [ -unit { b | kb | mb | gb | tb | pb } ] [ -name new_name_arg ] [ -cache { readwrite | readonly | none } ] [ -tier { tier0_flash | tier1_flash | tier_enterprise | tier_nearline } ] [ -easytier { on | off } ]
mkvdisk -mdiskgrp { mdisk_group_id | mdisk_group_name } -vtype image -mdisk { mdisk_id_list | mdisk_name_list } [ -iogrp { io_group_id | io_group_name } ] [ -size disk_size ] [ -accessiogrp { iogrp_id_list | iogrp_name_list } ] [ -fmtdisk ] [ -nofmtdisk ] [ -rsize { disk_size | disk_size_percentage% | auto } [ -warning { disk_size | disk_size_percentage% } ] [ -autoexpand ] [ -grainsize { 32 | 64 | 128 | 256 } ] ] [ -import ] [ -copies num_copies [ -createsync ] [ -syncrate syncrate ] ] [ -mirrorwritepriority { latency | redundancy } ] [ -udid vdisk_udid ] [ -node { node_name | node_id } ] [ -unit { b | kb | mb | gb | tb | pb } ] [ -name new_name_arg ] [ -cache { readwrite | readonly | none } ] [ -easytier { on | off } ]
Parameters
- -mdiskgrpmdisk_group_id_list | mdisk_group_name_list
- (Required) Specifies one or morestorage 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.
- -iogrpio_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 this does not affect moving to the recovery I/O group).
- -accessiogrpiogroup_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 any access I/O
groups are specified, only those I/O groups are in the access set (including if that set does not
include the caching I/O group).
- -udidvdisk_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).
- -sizedisk_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. This 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.
- -rsizedisk_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 fully
allocated. 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.
- -fmtdisk
- (Optional) Specifies that the volume be formatted. This parameter is no longer required for any
volumes.
This parameter is not required when creating fully allocated volumes. The format
operation is automatically applied to fully allocated 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, fully allocated, 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, fully allocated, and non-image mode volumes, and you can specify this parameter to turn it off.
- -compressed
- (Optional) Enables compression for the volume. This parameter must be specified with
-rsize and cannot be specified with -grainsize.
- -warningdisk_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.
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:
- Enabled, the default value for -warning is 80% of the volume capacity.
- 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. This
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.
- -grainsize32 | 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.
- -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.
- -syncrate syncrate
- (Optional) Specifies the copy synchronization rate. A value of zero (0)
prevents synchronization. The default value is 50. See Relationship between the rate value and the data copied per second for the supported
-syncrate values and their corresponding rates. Use this parameter to alter the
rate at which the fully allocated volume or mirrored volume format before synchronization.
- -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.
- -mirrorwriteprioritylatency | redundancy
- (Optional) Specifies how to configure the mirror write algorithm priority. If not specified, the
default value is latency.
- 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.
- 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.
- -vtypeseq | striped | image
- (Optional) Specifies the virtualization type. When creating sequential or image mode volumes,
you must also specify the -mdisk parameter. The default virtualization type is
striped.
- -nodenode_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 required for the
subsystem device driver (SDD). The system chooses a default if you do not supply this
parameter.
- -unitb | kb | mb | gb | tb | pb
- (Optional) Specifies the data units to use in conjunction with the capacity that
is specified by the -size and -rsize parameters. The
default unit type is MB.
- -mdiskmdisk_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 creating 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.
- -namenew_name_arg
- (Optional) Specifies a name to assign to the new volume.
- -cachereadwrite | 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.
- -tiertier0_flash | tier1_flash | tier_enterprise |
tier_nearline
- (Optional) Specifies the MDisk tier when an image mode copy is added.
- 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.
- 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 mirrored volume with two image
mode copies by using this command.
- -easytieron | off
- Determines if the IBMEasy 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.
Note: The Easy Tier feature is not enabled. The status is always
inactive.
If the Easy Tier
feature is enabled, and if a volume copy is striped and not being migrated, the following table
applies:
Description
This command creates a new volume object. You can use the command to create various types of
volume
objects, making it one of the most complex commands.
Remember: You can create a striped volume only in a child pool - you cannot create sequential
or image volumes in a child pool.
You must decide which storage
pool or storage pools provide the storage for the volume. Use the lsmdiskgrp command
to list the available storage pools and the amount of free storage
in each pool. If you are creating a volume with more than one copy,
each storage pool that you specify must have enough space for the
size of the volume.
Important: The extent size for the storage pool can limit volume size. Consider the
maximum volume size that you want to use when creating storage pools. Refer to the information on
creating storage pools for a comparison of the maximum volume capacity for each extent size. The
maximum is different for thin-provisioned volumes.
Choose
an I/O group for the volume. This action determines which nodes in
the system process the I/O requests from the host systems. If you
have more than one I/O group, ensure that you distribute the volumes
between the I/O groups so that the I/O workload is shared evenly between
all nodes. Use the
lsiogrp command to show the
I/O groups and the number of volumes that are assigned to each I/O
group.
Note: It is normal for systems with
more than one I/O group to have storage pools that have volumes in
different I/O groups. FlashCopy processing
can make copies of volumes whether the source and target volumes
are in the same I/O group. If, however, you plan to use intra-system
Metro or Global Mirror operations, ensure that both the master and
auxiliary volume are in the same I/O group.
The command returns
the IDs of the newly created volume.
An encryption key cannot
be used when creating an image mode MDisk. To use encryption (when
the MDisk has an encryption key), the MDisk must be self-encrypting.
Specify the virtualization type by using
the -vtype parameter; the supported types are
sequential (seq), striped, and image.- sequential (seq)
- This virtualization type creates the volume that uses sequential
extents from the specified MDisk (or MDisks, if creating multiple
copies). The command fails if there are not enough sequential extents
on the specified MDisk.
- striped
- This is the default virtualization type. If the -vtype parameter is not
specified, striped is the default; all managed disks in the storage pool
are used to create the volume. The striping is at an extent level; one extent from each
managed disk in the group is used. For example, a storage pool with 10 managed disks uses one extent
from each managed disk. It then uses the 11th extent from the first managed disk, and so on.
If
the -mdisk parameter is also specified, you can supply a list of managed disks
to use as the stripe set. This can be two or more managed disks from the same storage pool. The same
circular algorithm is used across the striped set. However, a single managed disk can be specified
more than once in the list. For example, if you enter -mdisk 0:1:2:1, the extents
are from the following managed disks: 0, 1, 2, 1, 0, 1, 2, and so forth. All MDisks that
are specified in the -mdisk parameter must be in the managed mode.
A
capacity of 0 is allowed.
- image
- This virtualization type allows image mode volumes to be created when a managed disk already has
data on it, perhaps from a previrtualized subsystem. When an image mode volume is created, it
directly corresponds to the (previously unmanaged) managed disk that it was created from.
Therefore, except for thin-provisioned image mode volumes, volume logical block address (LBA)
x equals managed disk LBA x. You can use this command to bring
a nonvirtualized disk under the control of the system. After it is under the control of the system,
you can migrate the volume from the single managed disk. When it is migrated, the volume is no
longer an image mode volume.
You can add image mode volumes to an already populated storage pool
with other types of volumes, such as a striped or sequential.
Important: An image mode
volume must be 512 bytes or greater. At least one extent is allocated to an image mode volume.
Remember: If you create a mirrored volume from two image mode MDisks without
specifying a -size value, the capacity of the resulting volume is the smaller
of the two MDisks, and the remaining space on the larger MDisk is not accessible.
Attention: - Do not create a volume in an offline I/O group. You must ensure
that the I/O group is online before you create a volume to avoid any
data loss. This action applies in particular to re-creating volumes
that are assigned the same object ID.
- To create an image mode disk, you must already have a quorum disk
present in the system because an image mode disk cannot be used to
hold quorum data. Refer to information on quorum disk creation for
more details.
- The command fails if either limit of 2048 volumes per I/O Group
or 8192 volume copies per system is reached.
The rate at which the volume copies resynchronize after loss
of synchronization can be specified by using the
-syncrate parameter.
This table provides the relationship of the
syncrate value to the data copied per second.
Note: These settings also affect
the initial rate of formatting.
Table 1. Relationship between the rate value and the data copied per
second
| User-specified rate attribute value |
Data copied/second |
| 1 - 10 |
128 KB |
| 11 - 20 |
256 KB |
| 21 - 30 |
512 KB |
| 31 - 40 |
1 MB |
| 41 - 50 |
2 MB |
| 51 - 60 |
4 MB |
| 61 - 70 |
8 MB |
| 71 - 80 |
16 MB |
| 81 - 90 |
32 MB |
| 91 - 100 |
64 MB |
An invocation example
mkvdisk -mdiskgrp Group0 -size 0
-iogrp 0 -vtype striped -mdisk mdisk1 -node 1
The resulting output:
Virtual Disk, id [1], successfully created
An invocation example for creating
an image mode volume
mkvdisk -mdiskgrp Group0
-iogrp 0 -vtype image -mdisk mdisk2 -node 1
The resulting output:
Virtual Disk, id [2], successfully created
An invocation example
An
invocation example for creating a new volume
mkvdisk -mdiskgrp Group0 -size 0 -unit kb
-iogrp 0 -vtype striped -mdisk mdisk1 -node 1 -udid 1234 -easytier off
The resulting output:
Virtual Disk id [2], successfully created
An invocation example for creating
a thin-provisioned volume
mkvdisk -mdiskgrp Group0 -iogrp 0 -vtype striped -size 10 -unit gb -rsize 20% -autoexpand -grainsize 32
The
resulting output:
Virtual Disk id [1], successfully created
An invocation example for creating a compressed volume copy
mkvdisk -mdiskgrp 0 -iogrp 0 -size 1 -unit tb -rsize 0 -autoexpand -warning 0 -compressed
The resulting output:
Virtual Disk id [1], successfully created
An invocation example for creating
a mirrored image-mode volume
mkvdisk -mdiskgrp Group0:Group0 -mdisk mdisk2:mdisk3 -iogrp 0 -vtype image -copies 2
The
resulting output:
Virtual Disk id [1], successfully created
An invocation example for creating
a mirrored volume
mkvdisk -iogrp 0 -mdiskgrp 0:1 -size 500 -copies 2
The
resulting output:
Virtual Disk id [5], successfully created
An invocation
example for configuring a mirror write algorithm priority
mkvdisk -mdiskgrp Group0 -iogrp 0 -vtype striped -mirrorwritepriority redundancy -size 500
The resulting output:
Virtual Disk id [5], successfully created
An invocation
example to create a disk with default grain size
mkvdisk -iogrp 0 -mdiskgrp 0 -size 100 -rsize 5%
The
resulting output:
Virtual Disk id [5], successfully created
An invocation example for creating a volume with I/O groups 0 and 1 in its I/O group access
set
mkvdisk -iogrp 0 -mdiskgrp 0 -size 500 -accessiogrp 0:1
The resulting output:
Virtual Disk id [5], successfully created
An invocation
example for creating a volume with warning considerations
mkvdisk -mdiskgrp 6 -size 200 -rsize 50 -iogrp 0
The resulting output:
Virtual Disk, id [2], successfully created
...
lsvdisk 2
...
warning 20 # threshold in MB = 50 x 80 / 100 = 40 MB; threshold as %age of volume capacity = 40 / 200 * 100 = 20
...
An invocation
example for creating a volume with warning considerations
mkvdisk -mdiskgrp 6 -size 200 -rsize 50 -iogrp 0 -warning 80%
The resulting output:
Virtual Disk, id [2], successfully created
...
lsvdisk 2
...
warning 80 # displayed as %age of volume capacity
...
An invocation
example for creating a volume with warning considerations
mkvdisk -mdiskgrp 6 -size 200 -rsize 50 -iogrp 0 -autoexpand
The resulting output:
Virtual Disk, id [2], successfully created
...
lsvdisk 2
...
warning 80 # displayed as %age of volume capacity
...
An
invocation example to create a volume with the read cache enabled
mkvdisk -iogrp 0 -size 10 -unit gb -mdiskgrp 0 -cache readonly
The resulting output:
Virtual Disk, id [2], successfully created
An invocation example
to create volume Group0
mkvdisk -mdiskgrp Group0 -iogrp io_grp0 -vtype image -mdisk 13 -node 1 -udid 1234 -tier tier_nearline
The
resulting output:
Virtual Disk, id [0], successfully created
An
invocation example to turn off formatting while creating volume Chelsea1
mkvdisk -mdiskgrp Chelsea1 -iogrp 0 -mdiskgrp 0:1 -size 500 -nofmtdisk -copies 2
The
resulting output:
Virtual Disk, id [0], successfully created