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From:Wm Mussatto Date:March 10 2010 5:11pm
Subject:Re: mysql & RAID
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On Wed, March 10, 2010 09:04, Dan Nelson wrote:
> In the last episode (Mar 10), John G. Heim said:
>> I have read (and have been told) to stay away from RAID-5 for
>> update-intensive systems.  Are there performance concerns with RAID-10
>> as
>> well?  We will be buying from Dell (done deal for reasons too
>> complicated
>> to go into) and the disks they're selling are 146 Gb.  I can get up to 8
>> of them in the server we're buying.  I asked them about just getting 2
>> big
>> disks and going with RAID-1.
>> My understanding is that with RAID-10, the system can do multiple reads
>> and
>> writes simultaneously so throughput is improved oversystems w/o RAID or
>> with
>> RAID-1. But the same logic would apply to RAID-5 only it doesn't work
>> out
>> that way.
> RAID-5 has an extra penalty on small random writes due to the I/O required
> to maintain the parity blocks (it does 2 reads and 2 writes for every
> write
> your app does).  RAID-10 is just a mirror so it doesn't have to worry
> about
> that.
> --
> 	Dan Nelson
> 	dnelson@stripped
If you can get the disk cheap you might want to get one or two extras and
keep them as spares.

William R. Mussatto
Systems Engineer

mysql & RAIDJohn G. Heim10 Mar
  • Re: mysql & RAIDDan Nelson10 Mar
    • Re: mysql & RAIDWm Mussatto10 Mar
  • Re: mysql & RAIDGlyn Astill11 Mar
  • Re: mysql & RAIDЕвгений Килимчук16 Mar
    • Re: mysql & RAIDJohn Daisley16 Mar