On Tue, Jan 12, 2010 at 12:37:30PM -0800, Gary Mills wrote: > On Tue, Jan 12, 2010 at 11:11:36AM -0600, Bob Friesenhahn wrote: > > On Tue, 12 Jan 2010, Gary Mills wrote: > > > > > >Is moving the databases (IMAP metadata) to a separate ZFS filesystem > > >likely to improve performance? I've heard that this is important, but > > >I'm not clear why this is. > > > > There is an obvious potential benefit in that you are then able to > > tune filesystem parameters to best fit the needs of the application > > which updates the data. For example, if the database uses a small > > block size, then you can set the filesystem blocksize to match. If > > the database uses memory mapped files, then using a filesystem > > blocksize which is closest to the MMU page size may improve > > performance. > > I found a couple of references that suggest just putting the databases > on their own ZFS filesystem has a great benefit. One is an e-mail > message to a mailing list from Vincent Fox at UC Davis. They run a > similar system to ours at that site. He says: > > Particularly the database is important to get it's own filesystem so > that it's queue/cache are separated. > > The second one is from: > > http://blogs.sun.com/roch/entry/the_dynamics_of_zfs > > He says: > > For file modification that come with some immediate data integrity > constraint (O_DSYNC, fsync etc.) ZFS manages a per-filesystem intent > log or ZIL. > > This sounds like the ZIL queue mentioned above. Is I/O for each of > those handled separately?
That's interesting... and if so, is there a way to designate a log device for a specific filesystem? Ray _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
