[Gluster-devel] Fwd: FSync tester

[Behrooz Shafiee]

Hello All,

 I was comparing the performance of different GlusterFS clients with each
other and came across an interesting result. I used fsync tester utility (
here <https://oss.oracle.com/~mason/fsync-tester.c> or here
<https://github.com/gregsfortytwo/fsync-tester>) which basically writes 1MB
to a file (same file, same offset and same size) and calls fsync on that
file and measures the time for fsync( only fsync time, write time is
calculated separately). It repeats the same scenario every 1 seconds. I
tried fsync tester with GlusterFS fuse client, GlusterFS NFS, and my own
filesystem which is also a fuse based file system and uses GlusterFS
libgfapi under the hood to store data. I collected 1000 data points
(latency) for each client and the result is attached to this email. It's
interesting that libgfapi performs almost 3 times better than FUSE and NFS
clients. On the other hand FUSE client of GlusterFS has a very high jitter
compared to the libgfapi and NFS.

Can anyone explain or comment about these results?

Thanks a lot,
-- 
Behrooz
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