Re: Simulating WAL on separate disks

"Guy Rouillier" <guyr(at)masergy(dot)com> writes:
> We are soon to be doing performance testing. Our testing environment
> contains 4 SCSI disks in a RAID5 configuration, while our production
> environment will have 6 SCSI disks, which I'm suggesting we allocate as
> 4 in RAID5 for data and 2 in RAID1 for WAL.

> Because we don't have separate disks for WAL in our test environment,
> I'd like to minimize the effect of WAL. I've read the sections in both
> the tuning guide and the base documentation, and I'm still a little
> unclear about fsync and wal_sync_method. If I set fsync FALSE, does
> this disable WAL entirely?

No, but in any case it would entirely invalidate any performance testing
you might do. fsync off is a completely different regime of operation
(unless perhaps you have hardly any updates).

regards, tom lane