Use the chmdisk command to modify the name or Easy Tier settings for a managed disk
(MDisk).
Syntax
chmdisk [ -namenew_name_arg ] [ -tier { tier0_flash | tier1_flash | tier_enterprise | tier_nearline } ] [ -easytierload { default | low | medium | high | very_high } ] [ -encrypt { yes | no } ] { mdisk_id | mdisk_name }
Parameters
- -namenew_name_arg
- (Optional) Specifies the new name to be applied to the managed disk.
- -tiertier0_flash | tier1_flash |
tier_enterprise | tier_nearline
- (Optional) Specifies the new tier of the MDisk. The values are:
- 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.
Note: Since Release 8.1.0, the tier of MDisks mapped from
certain types of IBMSystem Storage Enterprise Flash is
fixed to tier0_flash, and cannot be changed.
- -easytierloaddefault | low | medium | high | very_high
- (Optional) Specifies the Easy Tier load (amount)
to place on a non-array MDisk within its tier.
If
Easy Tier is either
overusing or under-utilizing a particular MDisk, modify the
easy_tier_load value to change the load size.
Note: Specifying
default returns the performance capability to the value used by
the system. Specify very_high only if the MDisk
tier is ssd.
- -encryptyes | no
- (Optional) Specifies whether the MDisk is encrypted by using its own encryption
resources. The values are yes or no.
Important: If you use SAN Volume Controller in front
of an encrypted Storwize V7000 system,
you must upgrade Storwize V7000 before
you apply encryption to your Storwize V7000 system.
If you apply encryption to your system, you must identify the encrypted MDisks
before you apply the encryption. If you specify
chmdisk -encrypt, the
setting is permanent in
SAN Volume Controller no matter
what
Storwize V7000
says.
- mdisk_id | mdisk_name
- (Required) Specifies the ID or name of the managed disk to modify.
Description
This command modifies the
attributes of a managed disk.
Do not use the
-encrypt parameter if one of the MDisk group's has an encryption key,
parent pool, and child pools. Use chmdisk for existing self-encrypting
MDisks before you start any migration. If an MDisk is self-encrypting, the encrypted
property defaults to what is reported.
If you are upgrading your system and the back end of the system uses encrypted storage, you
must indicate which MDisks are self-encrypting before you add MDisks to a storage pool. If
those MDisks are part of a storage pool, the system assumes that the back-end is not
self-encrypting (even if it might be).
If you create encrypted storage pools, the system encrypts locally before it sends data to
the back-end. So, the back-end of the system could encrypt again and cannot compress data
because the data is random and not compressible.
Note: You must upgrade the system
first.
To use encryption on the system that already has encryption that is enabled
on the back-end, upgrade the back-end of the system before you enable encryption on the
system.
An invocation
example
chmdisk -tier tier0_flash mdisk13
The
resulting output:
No feedback
An invocation
example
chmdisk -tier tier_nearline mdisk0
The
resulting
output:
MDisk Group, id [13], successfully created
An invocation
example
chmdisk -easytierload high mdisk0
The resulting
output:
MDisk Group, id [13], successfully created
An invocation
example
chmdisk -name my_first_mdisk -encrypt yes 0
The
resulting
output:
MDisk Group, id [0], successfully changed