On Wed, 8 Jul 2009, Moore, Joe wrote:
The copies code is nice because it tries to put each copy "far away" from the others. This does have a significant performance impact when on a single spindle, however, because each logical write will be written "here" and then a disk seek to write it to "there".
That's true for the worst case, but zfs mitigates that somewhat by batching i/o into a transaction group. This means that i/o is done every 30 seconds (or 5 seconds, depending on the version you're running), allowing multiple writes to be written together in the disparate locations.
Regards, markm _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
