Hello,
It's been a while since I've done AIX..., but I'm planning
a new TSM on AIX disk-only backup solution.
I'm planning to make an AIX volume group out of 40 luns of 1 TB.
I'm planning to create one big file system on here.
The purpose for this is to use this as a device class FILE for a TSM disk-only backup solution.
My question is,
would it make any difference, performance-wise, if I split up this capacity over multiple file systems, or even multiple VG's ?
right now this is the plan:
---------------------------------
- volume group: VG_TSMFILECLASS -> 40 luns of 1TB
-> one filesystem on there /FILECLASS/ -> 40 TB
- device class FILE has /FILECLASS/ specified as directory to work in (at TSM level)
(all backup data will be written to the same file system and VG)
would this be better?:
----------------------------
- volume group: VG_TSMFILECLASS -> 40 luns of 1TB
-> two filesystems on here: /FILECLASS1/ -> 20 TB
/FILECLASS2/ -> 20 TB
- device class FILE has /FILECLASS1/ + /FILECLASS2/ specified as diectories to work in
(when you specify multiple directories for a device class file in TSM, it spreads its volumes in
a balanced way over the directories that you specify,
so in this case the backups would be landing on 2 different filesystems in the same VG)
would this be even better ?:
------------------------------------
- volume group: VGTSMFILECLASS1 -> 20 luns of 1 TB
-> one FILESYSTEM on here: /FILECLASS1/
- volume group: VGTSMFILECLASS2 -> 20 luns of 1 TB
-> one FILESYSTEM on here: /FILECLASS2/
- device class FILE has /FILECLASS1/ + /FILECLASS2/ specified as diectories to work in
(when you specify multiple directories for a device class file in TSM, it spreads it volumes in
a balanced way over the directories that you specify,
so in this case the backups would be landing on 2 different VG's)
would this make a difference for performance or might I just as well put everything on one file system in one VG ?
Also is there some kind of optimal lun size for this (from an AIX OS perspective) ?
some extra info:
(without DIO since the TSM device class FILE works in a sequential way).
- all storage is on one dedicated storage box
(EMC Ax4 with 2TB SATA2 disks)
any hints/thoughts would be appreciated