Andy Huebner wrote:

We use RAID 5 (5+1) on a Clariion using 146GB drives.  We peak the drives at 
over 55MB/sec, sustained speed is over 45MB/sec.  How fast are you reading and 
writing to your disks?  If it is faster than your SAN storage can read and 
write from RAID 5 then mirroring or striping is a better choice, although I 
would not use unprotected disks.

Andy Huebner

-----Original Message-----
From:   ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU]  On Behalf 
Of Luc Beaudoin
Sent:   Tuesday, May 10, 2005 7:47 AM
To:     ADSM-L AT VM.MARIST DOT EDU
Subject:        [ADSM-L] Diskpool question

My diskpool is on a SAN,   I have to increase the size cause I'm taking
about 450GB per day and my diskpool is 350GB...

Is there a RAID issue for performance .... right now my diskpool is on a
RAID5 ... should I still use RAID5 or there a better RAID configuration??

thanks

Luc


This e-mail (including any attachments) is confidential and may be legally 
privileged. If you are not an intended recipient or an authorized 
representative of an intended recipient, you are prohibited from using, copying 
or distributing the information in this e-mail or its attachments. If you have 
received this e-mail in error, please notify the sender immediately by return 
e-mail and delete all copies of this message and any attachments.
Thank you.

Just for information, EMC did not optimize the FlareCode on Clariion for
RAIDGroup with even disk (3+1, 5+1, ...) so It could be better to use
4+1, 6+1, 8+1 RAIDGroup (See Clariion Best Practises on Powerlink). We
use a 4+1 configuration and during our backup database we have a
sustained speed of 70-80 MB/s.

Stripe on each disk is 64KB lenght, for four disk you have a full data
stripe of 256KB (4x64KB + 64KB Parity) and th default LTG size of AIX
Volume Group is 128kB.