Use the chmdisk command to modify the name or Easy Tier® settings for a managed disk
(MDisk).
Syntax
chmdisk [ -name new_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.
- -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 clustered system (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