Hello Dana,

normally I  create storage pools on RAID-5 protected disk arrays using 5
disks per RAID group for high performance on writing and short rebuild
times in case of hardware failures. Using larger RAID groups with 6, 7 or
more data drives were found to be very slow during RAID rebuild, sometimes
dataloss is caused because of a second disk failure, especially on SATA
drives. The only good for running RAID 1 is short rebiuld time; it does
not provide any additional performance, security, or avaibitlity.

Regards
Ullrich Maenz



Von:    Dana Holland <dana.holland AT NAVARROCOLLEGE DOT EDU>
An:     ADSM-L AT VM.MARIST DOT EDU
Datum:  09.08.2010 17:25
Betreff:        [ADSM-L] Raid 1 vs Raid 5
Gesendet von:   "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>



Does anyone have opinions about setting up storage pools as Raid 1 as
opposed to Raid 5?  We have a very limited amount of disk space at the
moment and don't know when we'll get approval to buy more.  At the time
we first started planning to implement TSM, we purchased what we thought
would be  plenty of storage.  But, that was 4 years ago - and our usage
has grown.  Now, if I choose Raid 1, I barely have enough to create a
primary and copy storage pool for one of our servers.  And that isn't
allowing for any growth at all.  And I'm not sure how much additional
space incremental backups would take.  I know Raid 5 would give me more
storage space, but I've also read that it's harder to recover from if
there's a disk failure (read this on a TSM site somewhere).  So, I'm
wondering what some of you are using?


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