topic Re: xp24000 change raid level in XP Storage

xp24000 change raid level

Grace Li — Wed, 16 Feb 2011 19:51:38 GMT

how to change raid 5 level to raid 1 for an existing lun in xp24000?

Re: xp24000 change raid level

Torsten. — Wed, 16 Feb 2011 21:06:17 GMT

IMHO no way.

While installing disk you decide about the RAID levels (e.g. 7+1, 4+4, 1+1, 3+1, etc ...), then you create LUNs on this RAID sets.

The only way to change is (IMHO) to delete everything, deinstall the disks (RAID groups) and start over.

Re: xp24000 change raid level

Grace Li — Wed, 16 Feb 2011 23:12:07 GMT

this is an unassigned lun. how to release it and then re-create? could you provide a step by step instruction?

Re: xp24000 change raid level

Torsten. — Thu, 17 Feb 2011 06:04:29 GMT

As said, the LUN RAID level is based on the disk group. Within a disk group all LUNs have he same RAID level.

Re: xp24000 change raid level

Alzhy — Thu, 17 Feb 2011 16:57:50 GMT

Grace

Note the architecture of a LUN/LDEV in a Hitachi (aka XP) array:

indidivual physical disks make up array groups
the disks are then configured into LDEVs of a particular RAID Type.
if you have an LDEV or disk/LUN that you want changed in RAID level - then the entire array group to which that ldev/disk/lun belongs to wil have to be re-inited.

That re-initialization can only be done by a Hitachi or XP tech. It is not an end user activity and cost $$. This is different from most controler centric arrays like EVAs and Netapps and Clarrions.

Hope this helps.

With Luv.

Alzhy Le'Cruel

Re: xp24000 change raid level

Alzhy — Thu, 17 Feb 2011 17:01:39 GMT

just to elaborate more:

All LDEVS in an array group will need to be at the same RAID Type.

Say you have array group 1-1 and it is composed of 8 disks. The HP/HDS engineer will carve it into a couple of standard sized ldevs (or disks/luns) all at the same RAID level. (Note there are also LDEV RAID configurations where the ldevs span accross several array groups)

So - you cannot request just one LDEV to be changed to a diferent RAID level.

It is good practice for plannning to be strictly done so you have Array Groups that are say RAID1 and others at RAID5

Re: xp24000 change raid level

Grace Li — Thu, 17 Feb 2011 17:01:52 GMT

thank you. that helps.