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.
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