RBN wrote: > I ran test_fsync on a local ext 3 partition and on a raid jfs SSD array > 8x32GB RAID10. The local disk returned quickly and gave what looks like > acceptable results. However, the RAID looks pretty bad. Any one have any > idea why fsync would take so long on an SSD RAID 10. As the original author of the test, all I can say is that those numbers look bad. :-( --------------------------------------------------------------------------- > > > LOCAL DISK > Simple write timing: > write 0.005460 > > Compare fsync times on write() and non-write() descriptor: > (If the times are similar, fsync() can sync data written > on a different descriptor.) > write, fsync, close 0.072429 > write, close, fsync 0.075627 > > Compare one o_sync write to two: > (o_sync unavailable) > (o_dsync unavailable) > write, fdatasync 0.075907 > write, fsync, 0.076320 > > Compare file sync methods with 2 8k writes: > (o_dsync unavailable) > write, fdatasync 0.108367 > write, fsync, 0.108659 > > > > RAID 10 SSD jfs > Simple write timing: > write 0.004843 > > Compare fsync times on write() and non-write() descriptor: > (If the times are similar, fsync() can sync data written > on a different descriptor.) > write, fsync, close 95.546382 > write, close, fsync 51.407276 > > Compare one o_sync write to two: > (o_sync unavailable) > (o_dsync unavailable) > write, fdatasync 10.999764 > write, fsync, 80.696959 > > Compare file sync methods with 2 8k writes: > (o_dsync unavailable) > write, fdatasync 111.931881 > write, fsync, 99.329298 -- Bruce Momjian <bruce@xxxxxxxxxx> http://momjian.us EnterpriseDB http://enterprisedb.com + None of us is going to be here forever. + -- Sent via pgsql-admin mailing list (pgsql-admin@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin
