Oracle Redo/Archive Logs w/T3 Raid 0+1 vs Raid 5

Oracle Redo/Archive Logs w/T3 Raid 0+1 vs Raid 5

Post by Rodrick Brow » Wed, 28 Aug 2002 09:37:37



I know im not the first to ask this but can anyone here share there
recommendations ?  Sun is telling us to use Raid 5 for Oracle redo/archive
logs but our DBA's is pushing for 0+1 with partner pairs which consumes way
two much disks I dont think it justify the cost. Anyone have any
recommendations ? were using 6960 iirc 1gig of cache per brick.

- Rodrick Brown
- Unix SA

 
 
 

Oracle Redo/Archive Logs w/T3 Raid 0+1 vs Raid 5

Post by Bill Tod » Wed, 28 Aug 2002 09:55:53



Quote:> I know im not the first to ask this but can anyone here share there
> recommendations ?  Sun is telling us to use Raid 5 for Oracle redo/archive
> logs but our DBA's is pushing for 0+1 with partner pairs which consumes
way
> two much disks I dont think it justify the cost. Anyone have any
> recommendations ? were using 6960 iirc 1gig of cache per brick.

You ought to be able to figure out your logging needs from the rate at which
your application generates log data and your tolerance for slightly
increased response times if you use RAID-5 and log forces require small
updates to disk.  For some installations, RAID-5 will prove adequate, for
others less so.

If your array provides battery-backed write-back cache such that log disk
writes can be safely deferred until, e.g., they fill up a full RAID-5
stripe, then a RAID-5 log should provide about the same throughput (and
response times) as a mirrored log of the same usable capacity (while
requiring only a bit more than half the disks).

- bill

 
 
 

1. More on RAID 0+1 ("RAID 10")

Dick Wilmot once said:

and Bruce Parker said:

and Roger B.A. Klorese emailed me:

Date: Wed, 23 Nov 94 18:37 PST


Subject: Re: RAID-10 ?
Newsgroups: comp.arch.storage


Organization: QueerNet
Cc:
Status: RO
X-Status: A

All incarnations of VERITAS Volume Manager do mirrored stripes (the
bogus "RAID-10").
--

2215-R Market Street #576         San Francisco, CA 94114       +1 415 ALL-ARFF
"There is only one real blasphemy -- the refusal of joy!"       -- Paul Rudnick

Posted with permission. Thanks Roger. Now I got it. All, even ancient Veritas
Volume Managers do RAID 0+1 (RAID 10).
--
                Dick Wilmot
                Editor, Independent RAID Report
                (510) 938-7425

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