zfs discuss - Dec 2006 - ZFS behavior under heavy load (I/O that is)

I''m observing the following behavior on our E2900 (24 x 92 config), 2
FCs, and ... I''ve a large filesystem (~758GB) with compress mode on.
When this filesystem is under heavy load (>150MB/S) I''ve problems
saving files in ''vi''. I posted here about it and recall that
the issue is addressed in Sol10U3. This morning I observed another variation of
this problem as follows:

- Create a file in ''vi'' and save it, session will hang as if
it is waiting for the write to complete.
- In another session you''ll observe the write from
''vi'' is indeed complete as evidenced by the contents of the
file.

Am I repeating myself here or is it a different problem all together.
 
 
This message posted from opensolaris.org

I think you may be observing that fsync() is slow.

The file will be written, and visible to other processes via the in-memory
cache, before the data has been pushed to disk. vi forces the data out via
fsync, and that can be quite slow when the file system is under load, especially
before a fix which allows fsync to work on a per-file basis. (In the S10U2 aka
6/06 Solaris release, fsync on ZFS forced all changes to disk, not just those of
the requested file.)
 
 
This message posted from opensolaris.org

Thanks, I just downloaded Update 3 and hopefully the problem will go away.
 
 
This message posted from opensolaris.org