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Re: SATA drives performance

From: gael(at)pilotsystems(dot)net ( Gaël Le Mignot)
To: Ognjen Blagojevic <ognjen(at)etf(dot)bg(dot)ac(dot)yu>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: SATA drives performance
Date: 2009-12-24 15:44:14
Message-ID: plop87637wwf5d.fsf@aoskar.kilobug.org (view raw or flat)
Thread:
Lists: pgsql-performance
Hello,

Instead of using 3 disks in RAID-0 and one without RAID for archive, I
would rather  invest into one  extra disk and  have either a  RAID 1+0
setup or use two  disks in RAID-1 for the WAL and  two disks in RAID-1
for the main database (I'm not sure which perform better between those
two solutions).

RAID-1 will  give you about twice as  fast reads as no  RAID (and RAID
1+0  will give  you twice  as  fast as  RAID 0),  with no  significant
penalty for writing, and it'll save  a lot of manpower in case on disk
dies.

If you can  afford hot-swappable disks, you can  even replace a failed
disk live, in a few minutes, with no failure at software level.

Everything  can be  remotely setup,  including adding/removing  a disk
from RAID  array, if  you use Linux  software RAID (mdadm),  except of
course  the physical  swap of  the disk,  but that  can be  done  by a
non-technician.

This  solution  costs  only  one  extra disk  (which  is  quite  cheap
nowadays) and  will deliver  enhanced performances and  save a  lot of
manpower and downtime in case of disk breaking.

Regards,

-- 
Gaël Le Mignot - gael(at)pilotsystems(dot)net
Pilot Systems - 9, rue Desargues - 75011 Paris
Tel : +33 1 44 53 05 55 - www.pilotsystems.net
Gérez vos contacts et vos newsletters : www.cockpit-mailing.com

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