On 2003-07-21 09:06:10 -0700, Josh Berkus wrote: > Alexander, > > > Hmmm. Seems to me that this setup would be better than one RAID5 with three > > 36Gb disks, wouldn't you think so? With one RAID5 array, I would still have > > the data and the WAL on one volume... > > Definitely. As I've said, my experience with RAID5 is that with less than 5 > disks, it performs around 40% of a single scsi disk for large read-write > operation on Postgres. > > If you have only 3 disks, I'd advocate one disk for WAL and one RAID 1 array > for the database. >
In this setup your database is still screwed if a single disk (the WAL disk) stops working. You'll have to revert to your last backup if this happens. The RAID-1 redundancy on your data disks buys you almost nothing: marginally better performance and no real redundancy should a single disk fail. I'd use RAID-5 if you absolutely cannot use more disks, but I would use RAID-10 or two RAID-1 partitions if you can afford to use 4 disks. Vincent van Leeuwen Media Design - http://www.mediadesign.nl/ ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
