mkdistributedarray

Use the mkdistributedarray command to create a distributed array and add it to a storage pool. (Use the mkarray command to create nondistributed arrays).

Syntax

 mkdistributedarray   -level  { raid5 | raid6 }  -driveclass driveclass_id    -drivecount  4 - 128   [  -stripewidth  3-16 ]   [  -allowsuperior  ]   [  -rebuildareas  {  1  |  2  |  3  |  4  } ] [  -rebuildareasgoal  {  0  |  1  |  2  |  3  |  4  } ]   [  -strip  {  128  |  256  } ]   [  -name  new_name_arg  ]   [  -encrypt  {  yes  |  no  } ]   [ -slowwritepriority { latency | redundancy } ]   {  mdiskgrp_id  |  mdiskgrp_name  }

Parameters

-levelraid5 | raid6
(Required) Specifies the RAID level for the array that is being created. The values are:
  • raid5
  • raid6
-driveclassdriveclass_id
(Required) Specifies the class that is being used to create the array. The driveclass_id must be a numeric value (specified with the lsdriveclass command).
-drivecount4 - 128
(Required) Specifies the number of drives to use for the array. The minimum drive count for:
  • RAID-5: 4
  • RAID-6: 6
-stripewidth3-16
(Optional) Indicates the width of a single unit of redundancy within a distributed set of drives. The value must be:
  • RAID-5: 3 - 16
  • RAID-6: 5 - 16

The default width for RAID-6 is 12 and the default width for RAID-5 is 10. The width plus the number of rebuild areas must be less than or equal to the drive count.

-allowsuperior
(Optional) Specifies that you can use drives that are not an exact match to the drive class used when creating the array (such as drives that use different capacity or technology). The system attempts to select the closest match to the class when satisfying the drive count. You can select higher capacity members of the same technology type before you select higher technology members.
Note: For a drive A to be considered superior to drive B, these situations must be true:
  1. Drives A and B are use=candidate
  2. Drives A and B are in the same I/O group.
  3. Drive A's speed (RPM) is equal to or greater than drive B's. Solid-state drives (SSDs) are higher speed than all hard disk drives (HDDs).
  4. Drive A's capacity is equal to or greater than drive B's.
  5. Drive A has a block size that is smaller than or equal to drive B.
-rebuildareas1 | 2 | 3 | 4
(Optional) Specifies the reserved capacity that is distributed across all drives available to an array. This capacity restores data after a drive failure. The values are:
  • 1
  • 2
  • 3
  • 4
The value is 1 - 4 (inclusive) for RAID-5 and RAID-6 arrays.
The default number of rebuild areas increases as the drive count increases.
Note: The number of rebuild areas plus the stripe width must be less than or equal to the total drive count.
-rebuildareasgoal0 | 1 | 2 | 3 | 4
(Optional) Specifies the number of rebuild areas that the array can target to keep available. If the number available in the array falls below this number, a system alert is raised.
Note: The goal value should not exceed the number of rebuild areas that are specified for the array.
The values are:
  • 0
  • 1
  • 2
  • 3
  • 4
-strip128 | 256
(Optional) Specifies the strip size in KiB for the array that is being configured. The values are 128 or 256.
Note: This command fails if 128 is specified and the size of the candidate drives is greater than 4 TB.
-namenew_name_arg
(Optional) Specifies the name of the array.
-encryptyes | no
(Optional) Specifies the array to encrypt. The values are yes and no. This parameter defaults to yes when lsencryption has its status set to enabled and all nodes in the I/O group that the array is being defined on are encryption-capable.
Note: The value can be yes only if encryption is enabled on the array's I/O group.
If you specify -encrypt yes when the I/O group does not support encryption, the command fails.
-slowwriteprioritylatency | redundancy
(Optional) Controls array ability to complete write operations that take too long, even if it temporarily compromises redundancy.
The value can be either latency or redundancy:
  • latency implies that the feature is enabled for normal I/O operations
  • redundancy implies that the feature is not enabled for normal I/O operations
The default value is latency mode for existing arrays).
Important: An array can cause member drives to become unsynchronized (to preserve response time) if the value is latency. If the value is redundancy, the array cannot cause member drives to become unsynchronized (to preserve time) and I/O performance is impacted.
mdiskgrp_id | mdiskgrp_name
(Required) Indicates the MDisk array ID or name.

Description

This command creates distributed arrays.

Remember: You cannot create an unencrypted array to add to an encrypted storage pool.
Each distributed array occupies 16 slots, which start at an MDisk ID that is divisible by 16. See the lsmdisk command for more information.

An invocation example to create an array that uses 40 drives of class 3 with 3 rebuild areas

 mkdistributedarray -level raid6 -driveclass 3 -drivecount 40 -stripewidth 10 -rebuildareas 3 mdiskgrp5

The detailed resulting output:

MDisk, id [16], sucessfully created

An invocation example to create an array with a drive class

 mkdistributedarray -level raid5 -driveclass 0 -drivecount 56 -stripewidth 8 -allowsuperior mdiskgrp2

The detailed resulting output:

MDisk, id [32], sucessfully created

An invocation example to create an array with maximum rebuild areas that logs an error on using the second rebuild area

mkdistributedarray -level raid5 -driveclass 5 -drivecount 60 -rebuildareas 4 -rebuildareasgoal 3 mdiskgrp2

The detailed resulting output:

MDisk, id [16], sucessfully created

An invocation example to create an array that might affect I/O performance

mkdistributedarray -driveclass 10 -slowwritepriority redundancy 0

The detailed resulting output:

MDisk, id [32], sucessfully created

An invocation example to make an encrypted distributed array that uses 40 drives of class 3 with three rebuild areas

mkdistributedarray -level raid6 -driveclass 3 -drivecount 40 -stripewidth 10 -rebuildareas 3 -encrypt yes mdiskgrp5

The detailed resulting output:

MDisk, id [16], sucessfully created