On Tue, Feb 14, 2017 at 7:23 PM, James Sewell <james.sew...@jirotech.com> wrote:
> OK, > > So with some help from the IRC channel (thanks macdice and JanniCash) > it's come to light that my RAID1 comprised of 2 * 7200RPM disks is > reporting ~500 ops/sec in pg_test_fsync. > > This is higher than the ~120 ops/sec which you would expect from 720RPM > disks - therefore something is lying. > > Breaking up the RAID and re-imaging with JBOD dropped this to 50 ops/sec - > another question but still looking like a real result. > > So in this case it looks like the RAID controller wasn't disabling caching > as advertised. > yup -- that's the thing. Performance numbers really tell the whole (or at least most-) of the story. If it's too good to be true, it is. These days, honestly I'd just throw out the raid controller and install some intel ssd drives. merlin
