On Sat, Apr 18, 2009 at 08:38:59AM +1000, Neil Brown wrote: > To restart your array, simple use the "--force" flag. > It might be valuable to also add "--verbose" so you can see what is > happening. > So: > > mdadm -S /dev/md1 > mdadm -A /dev/md1 -fv /dev/sd[abcde]4 > > and report the result. Hi Neil, Thanks for the kind and exceptionally helpful response. It was much appreciated. It greatly improved my understanding of both the problem and md generally. As it happens, I'd issued the following command some time before your message arrived: $ mdadm --assemble --run /dev/md1 /dev/sd[bcde]4 Fortunately, my impatience (after nearly a week of grief) was not rewarded by the punishment it probably deserved ;-) [Note 1] After many more hours /dev/md1 had resynched and recovered, using sdbe4 as the spare. The system then rebooted perfectly. Unfortunately, I then stupidly installed a new kernel, forgetting that Debian/Ubuntu would then update grub. So now I can boot kernels which reside on /dev/md0 from grub, but they don't find the root file system, which is also on /dev/md0. Needless to say, I'd find this a little easier to understand if the booting kernel didn't actually sit on the root filesystem itself. Obviously I need to fix grub, but I'm not sure how. I'm guessing that I have to do one or both of the following: 1. Tweak the root parameters for grub or the kernel in menu.lst 2. Update/reinstall parts of the bootloader on my MBRs or partitions. Sadly, my understanding of grub is a bit flaky, and my understanding of how it handles raid arrays is even flakier. I'd appreciate some advice, but fully understand that the new problem is slightly off-topic for this list, so I'm not expecting anything. By the way, once I've sorted grub (and backed up my business-critical data), I'll run your suggested command on the original disks and report back. In the real world I have decades of experience as a technical writer and teacher. So, once I've educated myself a bit more, I'd like to contribute by helping to improve the fragmented and outdated documentation that I've found over the course of the last week. Best wishes, Dave [Note 1] I should add that my impatient act was not 100% reckless, since I had previously dd'd all 5 1TB disks and was operating only on the copies. -- 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
