All the disks are usually laid out in a single RAID 10 stripe . There are no dedicated disks for the OS/WAL as storage is a premium On Wed, Apr 28, 2010 at 10:30 PM, Greg Smith <greg@xxxxxxxxxxxxxxx> wrote: > Anj Adu wrote: >> >> We do not archive the WALs. We use application-level replication to >> achieve redundancy. WAL archiving was difficult to support with the >> earlier hardware we had ( 6x300G 10K disks Dell 2850) given the >> volumes we were dealing with. The RAID card should be from the same >> manufacturer (LSI in Dell's case). >> > > The database is generating WAL files that are written to the pg_xlog > directory. Sometimes this is broken out into a separate drive so that it's > possible to measure how much I/O is being written to there, as opposed to > the main database drive. That's the WAL writing I was asking about, not the > overhead of archiving WAL files to elsewhere. The way that WAL writes go to > disk, you can't always speed them up just by throwing more disks at > them--sometimes, you just need the individual disk involved to be as fast as > possible. > > You should try to get the same Dell RAID controller you're already using, > that you know delivers good performance running your app. All I've heard > about the models released after the Perc 6i has been bad news. Dell varies > how much they tinker with the LSI firmware in their own version of each > card, and they didn't do very much of that in the Perc 6 series. They seem > to be changing around the newer models more again, which is always bad news. > > -- > Greg Smith 2ndQuadrant US Baltimore, MD > PostgreSQL Training, Services and Support > greg@xxxxxxxxxxxxxxx www.2ndQuadrant.us > > -- Sent via pgsql-admin mailing list (pgsql-admin@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin
