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/
3004B Poston Avenue
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615-469-5150 x802
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