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From:Glyn Astill Date:March 11 2010 10:31am
Subject:Re: mysql & RAID
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--- On Wed, 10/3/10, John G. Heim <jheim@stripped> wrote:

> Hi,
> I am working on configuring a new hardware database server.
> I'm a little confused as to what to do about disk. We have
> several mysql databases but by far the 2 most active are
> spamassassin bayesian rules and horde3/imp web mail. Both do
> a lot of updates. The bayesian rules are added to each time
> a spam message comes in for any of our 200 users. And the
> horde3/imp writes address book updates and preferences quite
> often.
> 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.
> I just want to make sure I'm configuring this system
> correctly before I order it.

As dan already stated, the write penalty of raid 5 doesn't really make it a good fit for
databases, go with raid 10.

Like you for reasons beyond my control I've been stuck with dell hardware, just beware of
dell raid controllers. The perc6 isn't too bad, however I still swap them out for more
capable controllers. Pretty much everything before the perc6 is complete junk.

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