On 13/08/12 16:31, Michael Tokarev wrote: > On 13.08.2012 18:20, Dmitrijs Ledkovs wrote: >> On 13/08/12 12:43, Michael Tokarev wrote: >>> On 13.08.2012 14:10, Miquel van Smoorenburg wrote: >>>> Package: mdadm >>>> Version: 3.2.5-1 >>>> Severity: serious >>>> Tags: patch wheezy sid >>>> >>>> The initramfs hook supplied by mdadm doesn't install mdmon. Also, mdmon >>>> is not included in the .udeb for the installer. >>>> >>>> This means that if you have an array with external metadata (ddf or, >>>> more widely used, imsm - Intel Matrix Raid) that it will come up >>>> readonly. This causes the installer to hang or the system not being >>>> able to boot if root is on that array. >>> >>> I'm not sure this is the right course of actions -- speaking of the >>> initramfs part, not about the d-i part. >>> >>> Why the system is not being able to boot if root is on such an array? >> >> I disagree with Michael, and agree with Miquel. mdmon is needed in the >> initramfs and I wanted to propose it's inclusion myself as well. >> >> Reading mdmon(8) section START UP AND SHUTDOWN, I am convinced that >> mdmon is required when rootfs is on an external metadata array. Does it >> make sense to you, Michael? > > 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. Can we include mdmon conditionally, if rootfs is on external metadata raid? > 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? =) -- Regards, Dmitrijs. -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
