Re: San & single point of failure
- From: "Mark Brinsmead" <pythianbrinsmead@xxxxxxxxx>
- To: QuijadJC@xxxxxxxxxxxxxxx
- Date: Tue, 18 Nov 2008 19:30:20 -0700
What? Why beware of that? In some places I have been, this might be the *
good* stuff! :-) (And yes, I *do* subscribe to BAARF.)
What you *really* need to worry about is the situation where some idiot
gives you a RAID-1 where the two mirrored volumes are at either end of the
*same disk*! Not only is there no protection, but the performance is the
stuff of nightmares.
Sadly, many RAID vendors actually claim that RAID-5 (well, *their* RAID-5,
anyway) is just as good as RAID-1. Or better. And many storage
administrators will believe them. Often there is nothing you can do about
this.
Happily, I have yet to encounter a storage vendor who claims that it is a *
good* idea to do RAID-1 with two slices of the same physical device. But
every now and again, you may see a storage administrator do it. Usually by
accident, I hope. Thankfully, I have never encountered this one first hand,
but I've seen close. :-)
On Tue, Nov 18, 2008 at 9:10 AM, QuijadaReina, Julio C <
QuijadJC@xxxxxxxxxxxxxxx> wrote:
> Beware also of SAN administrators who setup RAID 5 and later give that
> storage to DBA's for their databases. It does not hurt to double check what
> kind of underlying RAID they've got for you.
>
>
>
> Julio
>
>
> <...snip..>
>
--
Cheers,
-- Mark Brinsmead
Senior DBA,
The Pythian Group
http://www.pythian.com/blogs
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