RAID-5 and database servers

Eric Rostetter rostetter at mail.utexas.edu
Thu Mar 11 13:48:09 CST 2010


Quoting Jefferson Ogata <poweredge at antibozo.net>:

> I've got several hundred disks running on RAID 5 and I've had one actual
> full RAID failure in 10 years, and that was my fault.

You've been lucky! :)

In 10 years, I've think I've had 3 RAID 5 failures (all rebuilt without
problems).

> In terms of performance, depending on the workload, RAID 5 can
> outperform RAID 10.

Very true.

> Furthermore Oracle's recommendations are based on
> what appears to be 5-10-year-old data

I agree, it appears outdated to me also.

> Bear in mind
> also that now that Oracle is a hardware company, they'd just love you to
> buy almost twice as much disk (from them).

I doubt that is a driving factor here...

> *Again*, this is why if you have particular performance requirements,
> you should consult with your database vendor to determine what bandwidth
> and IOPS you need, and benchmark your gear using different RAID configs.

Or at a minimum, you need to define what your performance requirements are.
If you can't quantify your performance requirements, you're just guessing
and "taking a shot in the dark".

> You may find that RAID 5 is just fine performance-wise, and you can get
> around 1.7 times the storage capacity with the same rack space, heat,
> and power load over RAID 10. Asking here you're just going to get people
> parroting Oracle's stale recommendations and speculating wildly without
> knowing anything about your workload.

Well, the advise has been slightly better than that, but yes, we're all
speculating without knowing anything about the workload.  And I at least
have stated that in my posts/replies...

If a serious answer is needed, the OP needs to post the workload and
performance expectations at a minimum...

-- 
Eric Rostetter
The Department of Physics
The University of Texas at Austin

Go Longhorns!



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