Steve Poe <spoe@sfnet.cc> writes:
>> Well, it's less bad with 7 disks than it is with 3, certainly. However,there
>> is an obvious and quick gain to be had by splitting off the WAL logs onto
>> their own disk resource ... up to 14%+ performance in some applications.
>>
> Pardon my ignorance, but the WAL logs are comprised of pg_xlog and
> pg_clog? Their own disk resource, but not within the same channel of
> disks the database is on, right?
Just pg_xlog. Ideally you don't want any other traffic on the physical
disk pg_xlog is on --- the idea is that the write heads need to stay
over the current xlog file. I don't think it hurts too much to share a
controller channel though.
regards, tom lane
