tsmithnj@gmail.com wrote:
> If the Clariion CX600 issues writes to cache and performs the physical
> write asynchronously, does the stated benefit of raid 10 versus 5
> really exists?

Tested it on Clariion myself several years back, so I recommend, as always,
that you test it YOURSELF, but, yes the RAID5 write penalty is supressed or
hidden by massive caching by about 50% but ONLY if your write volume doesn't
exceed the write throughput of the array over some time period. Then
performance reverts to non-cached performance. And the data safety issue is
the big one for me, NOT the performance. RAID5 is NOT SAFE!

Art S. Kagel


> On Apr 16, 10:29 am, "Ray" <raymmailbox-n...@yahoo.com> wrote:
>
>>On Apr 16, 8:54 am, aj <ron...@mcdonalds.com> wrote:
>>
>>
>>
>>
>>
>>
>>>DB2 LUW v8.2 FP 14 RHAS 2.1
>>
>>>Not trying to start a flame war or anything, but does anyone have an
>>>opinion regarding whether to use Raid 5 or Raid 10 w/ DB2?
>>
>>>We have an EMC SAN (a Clariion CX600 I believe). My SysAdmin and I
>>>are discussing which raid type to use. Several years ago during my
>>>Informix DBA days, Art Kagel and other well-informed folks on C.D.I.
>>>would occasionally point out how raid 5 w/ database is a BAD idea, and
>>>how raid 10 should always be used.
>>
>>>With SAN advances (cache, memory, speed, etc..), does this still apply?
>>>My SysAdmin thinks Raid 5 is a better way to go.
>>
>>>All of my tablespace containers are DMS (typically 2 gigabytes each),
>>>except for temp space, which are SMS.
>>
>>>TIA
>>
>>>aj
>>
>>RAID 10 is still the better way to go for a database with a lot of
>>writes. For something like a data warehouse it might not be so
>>critical.- Hide quoted text -
>>
>>- Show quoted text -
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