On Wed, Oct 21, 2009 at 12:10 AM, Greg Smith <gsm...@gregsmith.com> wrote: > On Tue, 20 Oct 2009, Ow Mun Heng wrote: > >> Raid10 is supposed to be able to withstand up to 2 drive failures if the >> failures are from different sides of the mirror. Right now, I'm not sure >> which drive belongs to which. How do I determine that? Does it depend on the >> output of /prod/mdstat and in that order? > > You build a 4-disk RAID10 array on Linux by first building two RAID1 pairs, > then striping both of the resulting /dev/mdX devices together via RAID0.
Actually, later models of linux have a direct RAID-10 level built in. I haven't used it. Not sure how it would look in /proc/mdstat either. > You'll actually have 3 /dev/mdX devices around as a result. I suspect > you're trying to execute mdadm operations on the outer RAID0, when what you > actually should be doing is fixing the bottom-level RAID1 volumes. > Unfortunately I'm not too optimistic about your case though, because if you > had a repairable situation you technically shouldn't have lost the array in > the first place--it should still be running, just in degraded mode on both > underlying RAID1 halves. Exactly. Sounds like both drives in a pair failed. -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
