On Sun, Feb 13, 2011 at 3:54 PM, Scott Marlowe <scott.marlowe@xxxxxxxxx> wrote: > On Sun, Feb 13, 2011 at 1:12 PM, sergey <sergey.on.net@xxxxxxxxx> wrote: >> Hello, >> >> I got a disk array appliance of 8 disks 1T each (UltraStor RS8IP4). It will >> be used solely by PostgresQL database and I am trying to choose the best >> RAID level for it. >> >> The most priority is for read performance since we operate large data sets >> (tables, indexes) and we do lots of searches/scans, joins and nested >> queries. With the old disks that we have now the most slowdowns happen on >> SELECTs. >> >> Fault tolerance is less important, it can be 1 or 2 disks. >> >> Space is the least important factor. Even 1T will be enough. >> >> Which RAID level would you recommend in this situation. The current options >> are 60, 50 and 10, but probably other options can be even better. > > Unless testing shows some other level is better, RAID-10 is usually > the best. with software RAID-10 and 24 disks I can flood a 4 channel > SAS cable with sequential transfers quite easily, and for random > access it's very good as well, allowing me to reach about 5 to 6k tps > with a large pgbench db (-i -s 4000) ~ 40Gig Also, keep in mind that even if RAID5,6,50,60 are faster when not degraded, if they are degraded they will usually be quite a bit slower than RAID-10 with a missing drive. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
