Re: VOS and RAID 5

Viacheslav Leichinsky <v_leichinsky_at_ittoolbox.com> wrote:
>Dan Gould <dlg_nospam_at_cs.brown.edu> wrote in message news:<9k4rnl$2h$1_at_saturn.services.brown.edu>...
>> I ran across the Veritas/Oracle/Sun Initiative (www.vosinitiative.com)
>> recommended configurations. They seem to use a Sun T3 array configured
>> as a RAID 5. However, everything else I've seen denegrates the use of
>> RAID level 5 (primarily due to the overhead for small writes -- something
>> I anticipate doing a lot of in my DB) in favor of RAID 1+0.
>>
>> Should I ignore their recommendations? Or does the HW RAID support
>> overcome the disadvantes for level 5?

All other things being equal, RAID-5 offers worse write performance than RAID 1+0, clever hardware can reduce the cost but not eliminate it. However, RAID-5 may be adequate for your requirements, and is much more cost effective, if there's a chance to test, do so before committing yourself. If you've more budget than time, then just going for RAID 1+0 is a safe option.

>I think would be better to use RAID10 in your case - for write intensive
>application. BTW, I heard rumors regarding poor performance of sun disk arrays
>so Sun is going to sell HDS arrays.

I'm not experiencing problems with the Sun T3 arrays I'm using at the moment, if anything they're somewhat faster than I initially expected them to be.

-- 
Andrew Mobbs - http://www.chiark.greenend.org.uk/~andrewm/