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.
- -fmtdisk
- (Optional)
Specifies that the volume is formatted before it can be used. The -fmtdisk parameter formats (sets to all zeros) the extents
that make up this volume after it is created. If this parameter is
used, the command completes asynchronously; you can query the status
by using the lsvdiskprogress command.
Remember: You cannot specify this parameter with the -vtype image parameter.
The -fmtdisk parameter is not required when creating thin-provisioned volumes.
Thin-provisioned volumes return zeros for extents that have not been
written to.
The -fmtdisk parameter synchronizes
mirrored copies by default.
Important: You cannot format an image mode volume.
- -nofmtdisk
- (Optional) Specifies that the volume
not be formatted (for example, a mirrored volume).
Note: Formatting
is on by default for most volumes (such as single copy, fully allocated,
or non-image mode volumes) and can be turned off using this parameter.
- -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. This parameter also
requires that the -rsize parameter be specified.
- -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 Table 1 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.
- -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.
Remember: If you do not specify the -cache parameter, the default value (readwrite) is used.
- -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:
| 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 2) |
| Off |
One |
On |
inactive (see note 2) |
| Off |
Two |
Off |
inactive (see note 2) |
| Off |
Two |
On |
inactive (see note 2) |
| Measure |
One |
Off |
measured (see note 3) |
| Measure |
One |
On |
measured (see note 3) |
| Measure |
Two |
Off |
measured (see note 3) |
| Measure |
Two |
On |
measured (see note 3) |
| Auto |
One |
Off |
measured (see note 3) |
| Auto |
One |
On |
balanced (see note 4) |
| Auto |
Two |
Off |
measured (see note 3) |
| Auto |
Two |
On |
active (see note 5) |
| On |
One |
Off |
measured (see note 3) |
| On |
One |
On |
balanced (see note 4) |
| On |
Two |
Off |
measured (see note 3) |
| On |
Two |
On |
active (see note 5) |
Note:
- If the volume copy is in image or sequential mode or
is being migrated then the volume copy Easy Tier status is measured instead of active.
- 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.
- The default Easy Tier setting for a storage
pool is auto, and the default Easy
Tier setting for a volume copy is on. This means that Easy Tier functions except pool performance
balancing are disabled for storage pools with a single tier, and that
automatic data placement mode are enabled for all striped volume copies
in a storage pool with two or more tiers.
|
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.
You must use the -mdisk parameter to specify an MDisk that has a mode of
unmanaged. The -fmtdisk parameter cannot be used
to create 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