On Sat, Jul 11, 2009 at 1:40 AM, Peter Jeremy <peterjer...@optushome.com.au>wrote:
> On 2009-Jul-09 15:39:35 +0300, Dan Naumov <dan.nau...@gmail.com> wrote: > >A single 40 disk raidz (DO NOT DO THIS) will have 40 disks total, 39 > >disks worth of space and will definately explode on you sooner rather > >than later (probably on the first import, export or scrub). > > Can you provide a reference for this statement. AFAIK, the only > reason for the upper recommended limit of 9 disks is performance. > We found it impossible to re-silver a new/replacement drive in a 24-drive raidz2 vdev. Even after almost two weeks of trying, it never got above 20-30% complete before restarting. That led me to do a bunch of web searches, and found several blogs by Sun people that went over how the raidz implementation works, what the limitations are (limited to the IOps of a single drive), and the recommendation to never use more than 8 or 9 drives in any single vdev. -- Freddie Cash fjwc...@gmail.com _______________________________________________ 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"
