On Aug 8, 2006, at 5:28 PM, Joshua D. Drake wrote:
Thomas F. O'Connell wrote:
On Aug 8, 2006, at 4:49 PM, Joshua D. Drake wrote:
I am considering a setup such as this:
- At least dual cpu (possibly with 2 cores each)
- 4GB of RAM
- 2 disk RAID 1 array for root disk
- 4 disk RAID 1+0 array for PGDATA
- 2 disk RAID 1 array for pg_xlog
Does anyone know a vendor that might be able provide such setup?
Wouldn't it be preferable to put WAL on a multi-disk RAID 10 if
you had the opportunity? This gives you the redundancy of RAID 1
but approaches the performance of RAID 0, especially as you add
disks to the array. In benchmarking, I've seen consistent success
with this approach.
WALL is written in order so RAID 1 is usually fine. We also don't
need journaling for WAL so the speed is even faster.
In which case, which is theoretically better (since I don't have a
convenient test bed at the moment) for WAL in a write-heavy
environment? More disks in a RAID 10 (which should theoretically
improve write throughput in general, to a point) or a 2-disk RAID 1?
Does it become a price/performance question, or is there virtually no
benefit to throwing more disks at RAID 10 for WAL if you turn off
journaling on the filesystem?
--
Thomas F. O'Connell
Sitening, LLC
http://www.sitening.com/
3004B Poston Avenue
Nashville, TN 37203-1314
615-469-5150 x802
615-469-5151 (fax)
