I don't have a 2000 drive array (thats amazing!) but I do have two 280 drive arrays which are in production. Here are the generic stats:
server setup: OpenIndiana oi_151 1 server rack Dell r720xd 64g ram with mirrored 250g boot disks 5 x LSI 9207-8e dualport SAS pci-e host bus adapters Intel 10g fibre ethernet (dual port) 2 x SSD for log cache 2 x SSD for cache 23 x Dell MD1200 with 3T,4T, or 6T NLSAS disks (a mix of Toshiba, Western Digital, and Seagate drives - basically whatever Dell sends) zpool setup: 23 x 12-disk raidz2 glued together. 276 total disks. Basically each new 12 disk MD1200 is a new raidz2 added to the pool. Total size: ~797T We have an identical server which we replicate changes via zfs snapshots every few minutes. The whole setup as been up and running for a few years now, no issues. As we run low on space we purchase two additional MD1200 shelfs (one for each system) and add the new raidz2 into pool on-the-fly. The only real issues we've had is sometimes a disk fails in such a way (think Monty Python and the holy grail i'm not dead yet) where the disk hasn't failed but is timing out and slows the whole array to a standstill until we can manual find and remove the disk. Other problems are once a disk has been replaced sometimes the resilver process can take an eternity. We have also found the snapshot replication process can interfere with the resilver process - resilver gets stuck at 99% and never ends - so we end up stopping or only doing one replication a day until the resilver process is done. The last helpful hint I have was lowering all the drive timeouts, see http://everycity.co.uk/alasdair/2011/05/adjusting-drive-timeouts-with-mdb-on-solaris-or-openindiana/ for info. thanks, liam On Sun, Mar 6, 2016 at 10:18 PM, Fred Liu <[email protected]> wrote: > > > 2016-03-07 14:04 GMT+08:00 Richard Elling <[email protected]>: > >> >> On Mar 6, 2016, at 9:06 PM, Fred Liu <[email protected]> wrote: >> >> >> >> 2016-03-06 22:49 GMT+08:00 Richard Elling < >> [email protected]>: >> >>> >>> On Mar 3, 2016, at 8:35 PM, Fred Liu <[email protected]> wrote: >>> >>> Hi, >>> >>> Today when I was reading Jeff's new nuclear weapon -- DSSD D5's CUBIC >>> RAID introduction, >>> the interesting survey -- the zpool with most disks you have ever built >>> popped in my brain. >>> >>> >>> We test to 2,000 drives. Beyond 2,000 there are some scalability issues >>> that impact failover times. >>> We’ve identified these and know what to fix, but need a real customer at >>> this scale to bump it to >>> the top of the priority queue. >>> >>> [Fred]: Wow! 2000 drives almost need 4~5 whole racks! >> >>> >>> For zfs doesn't support nested vdev, the maximum fault tolerance should >>> be three(from raidz3). >>> >>> >>> Pedantically, it is N, because you can have N-way mirroring. >>> >> >> [Fred]: Yeah. That is just pedantic. N-way mirroring of every disk works >> in theory and rarely happens in reality. >> >>> >>> It is stranded if you want to build a very huge pool. >>> >>> >>> Scaling redundancy by increasing parity improves data loss protection by >>> about 3 orders of >>> magnitude. Adding capacity by striping reduces data loss protection by >>> 1/N. This is why there is >>> not much need to go beyond raidz3. However, if you do want to go there, >>> adding raidz4+ is >>> relatively easy. >>> >> >> [Fred]: I assume you used stripped raidz3 vedvs in your storage mesh of >> 2000 drives. If that is true, the possibility of 4/2000 will be not so low. >> Plus, reslivering takes longer time if single disk has bigger >> capacity. And further, the cost of over-provisioning spare disks vs raidz4+ >> will be an deserved >> trade-off when the storage mesh at the scale of 2000 drives. >> >> >> Please don't assume, you'll just hurt yourself :-) >> For example, do not assume the only option is striping across raidz3 >> vdevs. Clearly, there are many >> different options. >> > > [Fred]: Yeah. Assumptions always go far way from facts! ;-) Is designing > a storage mesh with 2000 drives biz secret? Or it is just too complicate to > elaborate? > Never mind. ;-) > > Thanks. > > Fred > > >> >> > *illumos-zfs* | Archives > <https://www.listbox.com/member/archive/182191/=now> > <https://www.listbox.com/member/archive/rss/182191/25482196-63d208bc> | > Modify > <https://www.listbox.com/member/?&;> > Your Subscription <http://www.listbox.com> > ------------------------------------------- openzfs-developer Archives: https://www.listbox.com/member/archive/274414/=now RSS Feed: https://www.listbox.com/member/archive/rss/274414/28015062-cce53afa Modify Your Subscription: https://www.listbox.com/member/?member_id=28015062&id_secret=28015062-f966d51c Powered by Listbox: http://www.listbox.com
