Hi everybody, many people, like myself, tested the performance of the ZFS filesystem by doing a "tar xf something.tar". Unfortunately, ZFS doesn''t handle this workload pretty well as all writes are being executed sequentially. So some people requested a multi-threaded tar... Well, here it comes: I have written a small patch that intercepts the write system calls an friends an passes them off to worker threads. I''d really like to see some performance metrics with this patch on a ZFS filesystem. Unfortunately, I am currently far from home, where I have such a system. I''d be pleased if you anybody could send me some results. Feedback and RFEs are also welcome. Get it here: http://www.maier-komor.de/mtwrite.html Cheers, Tom This message posted from opensolaris.org
Hello Thomas,
Thursday, January 25, 2007, 8:21:55 PM, you wrote:
TMK> Hi everybody,
TMK> many people, like myself, tested the performance of the ZFS
TMK> filesystem by doing a "tar xf something.tar". Unfortunately,
ZFS
TMK> doesn''t handle this workload pretty well as all writes are
being
TMK> executed sequentially. So some people requested a multi-threaded tar...
With ZFS as local file system it shouldn''t be a problem unless tar
fdsync''s each file but then removing fdsyncs would be easier.
In case of nfs/zfs multi-threaded tar should help but I guess not for
writes but rather for file/dirs creation and file closes. If you only
put writes to worker threads I''m not sure it will really help much if
any.
--
Best regards,
Robert mailto:rmilkowski at task.gda.pl
http://milek.blogspot.com
> Hello Thomas, > > With ZFS as local file system it shouldn''t be a > problem unless tar > fdsync''s each file but then removing fdsyncs would be > easier. > > In case of nfs/zfs multi-threaded tar should help but > I guess not for > writes but rather for file/dirs creation and file > closes. If you only > put writes to worker threads I''m not sure it will > really help much if > any. >write and close are sent to worker threads. For open I cannot imagine a way to parallelize the operations without rewriting tar completely. I''d be interested in both local ZFS and ZFS over NFS. Masking out the fdsyncs could be an easy enhancement. But Sun''s tar doesn''t do it anyway IIRC and star can be told to suppress the fdsyncs. This message posted from opensolaris.org