On Sun, Jan 24, 2010 at 8:34 PM, Jason Edwards <sub.m...@gmail.com> wrote: >> ZFS writes to a mirror pair >> requires two independent writes. If these writes go down independent I/O >> paths, then there is hardly any overhead from the 2nd write. If the >> writes >> go through a bandwidth-limited shared path then they will contend for that >> bandwidth and you will see much less write performance. > > What he said may confirm my suspicion on PCI. So if you could try the same > with "real" Serial ATA via chipset or PCI-e controller you can confirm this > story. I would be very interested. :P > > Kind regards, > Jason
This wouldn't explain why ZFS mirror on 2 disks directly, on the exact same controller (with the OS running off a separate disks) results in "expected" performance, while having the OS run off/on a ZFS mirror running on top of MBR-partitioned disks, on the same controller, results in very low speed. - Dan _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
