On Aug 8, 2006, at 6:24 PM, Joshua D. Drake wrote:
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?
Over 4 drives, I would gather that RAID 10 wouldn't gain you
anything. Possibly over 6 or 8 however, it may be faster because
you are writing smaller chunks of data, even if two copies of each.
Yeah, where I've seen the benefits in practice, the scenarios have
involved the availability of a minimum of 6 drives for a RAID 10 for
WAL. I really should do a comparison of a 2-disk RAID 1 with a
variety of multi-disk RAID 10 configurations at some point.
--
Thomas F. O'Connell
Sitening, LLC
http://www.sitening.com/
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