On 13.08.2012 19:40, Dmitrijs Ledkovs wrote: > On 13/08/12 16:31, Michael Tokarev wrote: [] >> Well. Sort of. mdmon utility is supposed to be used in the initramfs, >> with support of taking over, etc. But this is apparently due to defects >> in some filesystems (I guess it is ext[34]fs), which performs writes >> even if asked to do a read-only mount. I still don't see a reason why >> a _cleanly_ shut down system should have issues booting - I don't know >> which case Miquel referred to above when saying that a system does not >> boot. >> > > Well... based on the patch, my guess is that because the shutdown does > not wait for raid to be synchronised the filesystem ends up being dirty > after a "clean" shut down, hence to reliable boot you should (not must) > have mdmon with rootfs on external metadata raid.
Nononono. The _filesystem_ will most likely be clean. The raid array is not. > Can we include mdmon conditionally, if rootfs is on external metadata raid? There's no reason for that. mdmon is automatically started by mdadm if needed. >> BTW, is it still the case that ext4 performs writes behind the scenes >> even if asked for read-only mount? I think I've seen some fixes in >> this area, but it might be me dreaming. > > True. Maybe we should ask Ted? =) For this very question - including mdmon into initramfs - i really want to understand the underlying problem - whenever we're talking about ext[34]fs which applies journal even for readonly mount and STILL doing so in 3.2 kernel (wheezy), or something else -- in other words, if this is really necessary. I guess it wont _hurt_ to include it (*), after all, initramfs can sometimes be used as a small rescue system to modify the real root before it gets switched to. But I really want to see what is the problem we're dealing with. (*) ofcourse it needs to be verified - the takeover after booting into real system. I can't do it, since I don't have any spare system right now to install debian onto imsm array. I can only verify that the new takeover does not harm regular boot process without imsm arrays. This change - mdmon in initramfs - might be included to wheezy, it isn't a dramatic change. But I still don't think it is a good idea in general -- using native md arrays is a much better way. Due to the last statement, I'm not sure the severity of this bugreport is justified. /mjt -- To UNSUBSCRIBE, email to debian-bugs-rc-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
