On Fri, 5 Oct 2007, Bron Gondwana wrote: > We ran over 100,000 users on a single backend for over a year without > problems, but then we had a RAID array failure (3 disks within a day) > with 2Tb of data on a single RAID unit We have pretty much given up on RAID 5 because of the reconstruct times with large disks. Our new systems are 12 disk RAID 10 (plus hot spares). I think that gives about the same usable capacity as your 2 x RAID5 + 2 x RAID1 setup, but better redundancy. There would be twice as much work to restore the single RAID 10 set if it failed. I plan some experiments with split meta next year. My gut feeling is that 12 slow disks will be better than 4 faster disks given the short command queues in SATA NCQ, but I'm entirely willing to be proved wrong. Multiple partitions would certainly help with any bottlenecks at the VFS layer. I suppose that 8 SATA disks for the data and four 15k SAS disks for the metadata would be a good mix. -- David Carter Email: David.Carter@xxxxxxxxxxxxx University Computing Service, Phone: (01223) 334502 New Museums Site, Pembroke Street, Fax: (01223) 334679 Cambridge UK. CB2 3QH. ---- Cyrus Home Page: http://cyrusimap.web.cmu.edu/ Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html
