On 08/08/11 16:34, NeilBrown wrote: > On Fri, 05 Aug 2011 08:05:53 -0700 Daniel Frey <djqfrey@xxxxxxxxx> wrote: > >> Hi all, >> >> I've been fighting with my raid array (imsm - raid10) for several weeks >> now. I've now replaced all four drives in my array as the constant >> rebuilding caused a smart error to trip on the old drives; unfortunately >> mdadm is still resyncing the array at every boot. >> >> One thing I would like to clarify is does mdadm need to disassemble the >> array before reboot. At this point, I can't tell if my system is >> currently doing this. Googling around it seems some say that this step >> is unnecessary. > > With md arrays using "native" metadata you don't need to be too careful > shutting down. This is probably what you found by googling. > > With IMSM metadata it is a little easier to get it "wrong" though it should > normally work correctly. > > There is a program "mdmon" which communicates with the kernel and updates the > metadata on the devices. > > When there have been no writes for a little while, mdmon will notice and mark > the array as 'clean'. It will then mark it 'dirty' before the first write is > allowed to proceed. > On a clean shutdown of the array it will mark that array as 'clean'. > > But for you, the system shuts down with the array marked 'dirty'. This > suggests that on your machine 'mdmon' is being killed while the array is > still active. > > Presumably your root is on the IMSM RAID10 array? When the root filesystem > is marked 'read only' it will probably write to the filesystem to record that > a fsck is not needed. So the array will be 'dirty'. If you then halt before > mdmon has a chance to mark the array 'clean' you will get exactly the result > you see. That's correct, my root is on the imsm raid10 array, along with my dual-boot of Windows Vista. If I didn't want to boot Vista, I'd just be using native mdadm like I always have. > > If you arrange that the shutdown script runs > mdadm --wait-clean --scan > > after marking the root filesystem readonly, it will wait until all arrays are > recorded as 'clean'. I've done some quick poking around and I do not see anything like that. I'll look into it a little more and, if necessary, file a bug with the distro. > > This should fix your problem. > > What distro are you using? openSUSE has this command in /etc/init.d/reboot. I've used gentoo for as long as I can remember. I've never had an issue with mdadm on gentoo until I started using the imsm raid, so it's very possible that the above command is missing from the shutdown sequence. Thanks Neil! With this bit of information I should be able to get it resolved. I do have both mdadm and dmraid kernels on this machine now, so testing shouldn't be too hard. > > NeilBrown -- 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
