"NeilBrown" <neilb@xxxxxxx> writes: > On Mon, March 2, 2009 1:23 pm, Daniel Pittman wrote: >> John Robinson <john.robinson@xxxxxxxxxxxxxxxx> writes: >>> On 01/03/2009 08:52, Daniel Pittman wrote: >>> >>>> I have a random desktop machine here, running Debian/sid with a >>>> 2.6.26 Debian kernel. It has a two disk software RAID1, and >>>> apparently passes through a suspend/resume cycle correctly, but... [...] >> No, that appears to be about suspending and resuming access to the >> MD device while reconfiguring it; I don't /think/ that is accessed >> during a system-wide suspend/resume (aka hibernate, or s2disk) cycle. >> >> Certainly, it doesn't look like the path is invoked for that from my >> reading of the code. > > Correct, they are completely unrelated. > > I have never tried hibernating to an md array, but I think others > have, though I don't have a lot of specifics. > > One observation is that you really don't want resync to start before > the resume has completed. For this reason we have the 'start_ro' > parameter. Setting that to 1, e.g > > echo 1 > /sys/module/md_mod/parameters/start_ro > > will mean that resync will not start until the first write to the > array. The initrd should set this before assembling an md array to > load a resume image from. Ah. Debian already do this; see: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=415441 (Actually, since you wrote in that bug thread you already know. :) Hmmm. I have swap on LVM on MD, though, and I suspect that LVM writes to disk when it discovers and activates the volume groups... Let me try and find out. Then I can go and be grumpy, but at least complain to the right people about this. :) [...] > It should be that your observed symtpom of "check reports 48800 > mismatches" has nothing to do with hibernate/resume. OK. > Presumably you have swap on md/raid1 (as that is where hibenate > writes). The nature of swap writeout is that it is entirely possible > for different data to be written to each device of a raid1 when a page > is swapped out. > > However in that case, the data will never be read back in so the > apparent corruption is not a problem. Well, that is a relief, at least. > I would recommend that you run 'repair' before hibernating, to be sure > that the array is in-sync. Then hibenate/resume and see if it is > still in sync. I suspect it will be. That seems reasonable; I will test it. Regards, Daniel -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
