On Thu, Oct 16, 2008 at 2:32 PM, Eric Anopolsky <[EMAIL PROTECTED]> wrote: > On Thu, 2008-10-16 at 04:12 -0400, rektide wrote: >> Is there any case where the third and fourth disks would be >> used with -m raid1 -d raid1? > > Perhaps when the first pair of disks fill up? I don't know. I'm new > here.
I didn't check the code, that would be kind of a "linear append".. which is dump.... I was expecting a raid1 with 4 discs, to have exactly 3 copies of the original data, with each disk being a complete mirror. If we only have 1 copy (plus original), and therefore use only 2 disks for any individual write, probably, if we generate enough write load to make a couple of disks busy, it will use the second couple of disks also. Basically, the allocator should be able to balance the write load, and spread allocations to all devices.. however.. if the write load is insuficient to saturate a single pair of devices, there's no point in using the second pair.. it would just make the machine burn more watts This is pure speculation... Best thing is to look at the code. :) Kind regards, -- Miguel Sousa Filipe -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
