From: Ron <rjpeace@earthlink.net>
To: Joshua D. Drake <jd@commandprompt.com>
To: pgsql-performance@postgresql.org
Subject: Re: What's the best hardver for PostgreSQL 8.1?
Date: Sat, 24 Dec 2005 17:24:58 -0500
Message-ID: <6.2.5.6.0.20051224171301.01dd4e00@earthlink.net> (raw)
In-Reply-To: <43ADC0A8.20503@commandprompt.com>
References: <43A84D03.7090002@ritek.hu>
<docq5v$24ea$1@news.hub.org>
<200512212209.50234.caseroj@comcast.net>
<200512212231.55100.caseroj@comcast.net>
<20051224135042.484c6e32.frank@wiles.org>
<6.2.5.6.0.20051224161551.01dc5d98@earthlink.net>
<43ADC0A8.20503@commandprompt.com>
At 04:42 PM 12/24/2005, Joshua D. Drake wrote:
>>If you've got the budget or are dealing with small enough physical
>>storage needs, by all means use RAID 10. OTOH, if you are dealing
>>with large enterprise class apps like Sarbanes Oxley compliance,
>>medical and/or insurance, etc, etc, the storage needs can get so
>>large that RAID 10 for everything or even most things is not
>>possible. Even if economically feasible.
>>
>>RAID levels are like any other tool. Each is useful in the proper
>>circumstances.
>There is also RAID 50 which is quite nice.
The "quite nice" part that Joshua is referring to is that RAID 50
gets most of the write performance of RAID 10 w/o using nearly as
many HD's as RAID 10. OTOH, there still is a significant increase in
the number of HD's used, and that means MBTF's become more frequent
but you are not getting protection levels you would with RAID 10.
IME RAID 50 gets mixed reviews. My two biggest issues are
a= Admin of RAID 50 is more complex than the other commonly used
versions (1, 10, 5, and 6)
b= Once a HD failure takes place, you suffer a _permenent_
performance drop, even after the automatic volume rebuild, until you
take the entire RAID 50 array off line, reinitialize it, and rebuild
it from scratch.
IME "a" and "b" make RAID 50 inappropriate for any but the biggest
and most dedicated of DB admin groups.
YMMV,
Ron
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To: pgsql-performance@postgresql.org
Cc: rjpeace@earthlink.net, jd@commandprompt.com
Subject: Re: What's the best hardver for PostgreSQL 8.1?
In-Reply-To: <6.2.5.6.0.20051224171301.01dd4e00@earthlink.net>
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