On Sun, Feb 25, 2018 at 5:25 PM, Wol's lists <antlists@youngman.org.uk> wrote:
On 25/02/18 17:42, L A Walsh wrote:
I put 24 4tB Hitachi Ultrastars in them about 5-6 years ago. Have them setup as a RAID10, so only 48TB available storage, but if bought today, 6TB disks might be better buy.
Someone else will probably have to write the code, but I've been thinking about spec'ing a raid-60 or 61 mode for md-raid. 24 drives would make sense as 3 8-drive raid-6, so you'd have 18 data disks and 6 parity disks.
But this is a mode like linux raid-10 (which is *not* raid-1+0), so your data and parity would be scattered over all 24 drives. The important point of this is that if a drive fails, it gets rebuilt from all the other drives, and doesn't hammer just a few of them.
If that sounds like a good idea, I'm told it's probably only a minor mod to implement it ...
Cheers, Wol
Wol, Interesting idea about raid 60 and/or 61. In addition to the highspeed NAS / iSCSI server I need to build, I should probably build a 100TB archive NAS. Let's say a single raid 6 with 12 x 10TB drives. That seems to be about the limit of what I would want in a single raid 6, so raid 60 is at least interesting for volumes above 100TB. Even with a 12 x 10TB raid 6, I can't imagine how slow the rebuilds would be. Days? A week? Raid 61 would also be interesting. It seems to me the rebuild time on a raid 61 could be greatly faster than on just a 6 (or 60). That assumes the failed drive could just be copied over from the mirror pair of that drive. FYI: I've had Raid 6 rebuilds with 5 x 10TB shingled drives takes several days. It's pretty concerning to realize with RAID 6 on 10TB drives you only need a couple disk issues a couple days about to put your data at serious risk. Greg -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org