Hi Neil, Thank you for your answer. On Monday 27 December 2010 21:29:45 Neil Brown wrote: > On Mon, 27 Dec 2010 16:18:08 +0100 Laurent Pinchart wrote: > > Hi everybody, > > > > I've been struggling with a software RAID issue for several days now. > > Before sending the computer back to the vendor and asking for real RAID > > support, I'd like to try my luck here. > > By "real RAID" I assume you mean "proprietary closed-source raid that is > sold to you in an ROM" :-) Fair enough :-) > > The system as an Intel Matrix Storage SATA controller and two 250GB disks > > on which I want to use a RAID1. > > > > I've been able to create the array properly from a Gentoo installation CD > > (this might be a detail, but it might also influence homehost values, so > > I thought I'd mention it) with the metadata stored in IMSM format. > > > > Assembling the array automatically from the installation CD works. > > > > livecd ~ # mdadm --assemble --scan > > mdadm: Container /dev/md/imsm0 has been assembled with 2 drives > > mdadm: Started /dev/md/vol0_0 with 2 devices > > > > livecd ~ # cat /proc/mdstat > > Personalities : [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] > > md126 : active (auto-read-only) raid1 sda[1] sdb[0] > > > > 244195328 blocks super external:/md127/0 [2/2] [UU] > > > > md127 : inactive sdb[1](S) sda[0](S) > > > > 4514 blocks super external:imsm > > > > unused devices: <none> > > > > livecd ~ # cat /proc/partitions > > major minor #blocks name > > > > 7 0 94664 loop0 > > 8 0 244198584 sda > > 8 16 244198584 sdb > > 8 32 998400 sdc > > 8 33 998368 sdc1 > > 9 126 244195328 md126 > > > > 259 0 5242882 md126p1 > > 259 1 5242884 md126p2 > > 259 2 233709560 md126p3 > > > > So far, so good. > > > > I've then created an mdadm.conf file with mdadm -E --scan > > > > livecd ~ # mdadm -E --scan > > ARRAY metadata=imsm UUID=480da1d0:8150f280:7dd8425d:bec99c46 > > ARRAY /dev/md/vol0 container=480da1d0:8150f280:7dd8425d:bec99c46 member=0 > > UUID=17e28225:34f7c425:eb78aece:05c29a40 > > > > livecd ~ # mdadm --assemble --scan > > mdadm: Container /dev/md/imsm0 has been assembled with 2 drives > > mdadm: Started /dev/md/vol0 with 2 devices > > > > livecd ~ # cat /proc/mdstat > > Personalities : [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] > > md126 : active (auto-read-only) raid1 sda[1] sdb[0] > > > > 244195328 blocks super external:/md127/0 [2/2] [UU] > > > > md127 : inactive sdb[1](S) sda[0](S) > > > > 4514 blocks super external:imsm > > > > unused devices: <none> > > > > livecd ~ # cat /proc/partitions > > major minor #blocks name > > > > 7 0 94664 loop0 > > 8 0 244198584 sda > > 8 16 244198584 sdb > > 8 32 998400 sdc > > 8 33 998368 sdc1 > > 9 126 244195328 md126 > > > > 259 0 5242882 md126p1 > > 259 1 5242884 md126p2 > > 259 2 233709560 md126p3 > > > > Still good so far. The /dev/md/vol0_0 device is now called /dev/md/vol0. > > > > Copying the mdadm.conf file to initramfs and rebooting, the array is > > correctly assemble with mdadm --assemble --scan > > > > livecd ~ # mdadm --assemble --scan > > mdadm: Container /dev/md/imsm0 has been assembled with 2 drives > > mdadm: Started /dev/md/vol0 with 2 devices > > > > livecd ~ # cat /proc/mdstat > > Personalities : [raid1] > > md126 : active (read-only) raid1 sda[1] sdb[0] > > > > 244195328 blocks super external:/md127/0 [2/2] [UU] > > > > md127 : inactive sdb[1](S) sda[0](S) > > > > 4514 blocks super external:imsm > > > > unused devices: <none> > > > > However, no partitions are detected. > > > > livecd ~ # cat /proc/partitions > > major minor #blocks name > > > > 8 0 244198584 sda > > 8 16 244198584 sdb > > 8 32 998400 sdc > > 8 33 998368 sdc1 > > 9 126 244195328 md126 > > > > If I remove the /etc/mdadm.conf file from the initramfs image, the volume > > is detected as vol0_0 instead of vol0 and the partitions are correctly > > detected. > > > > I don't understand what's going on there, and how I could fix it. Help > > would be greatly appreciated. > > That is very strange.... > It might help if you could provide the complete boot logs so I can see > everything that happened leading up to the partitions not being there. It > would help me see if they were never created, or created then removed. > > The command > blockdev --rereadpt /dev/md/vol0 > should re-detect the partitions for you, so you could try doing something > with that as a temporary fix. > > mdadm does sometime remove partitions, but only on things that it is about > to include in an array, so it shouldn't ever remove the partitions > on /dev/md/vol0. > > So something odd is happening, and more logs are needed to guess what. I'll try to get more logs. In the meantime I've found something weird. If I run mdadm --assemble --scan twice in a row, the partitions are correctly created the second time. The next problem will be that the array is created in read-only mode. mdadm -- readwrite /dev/md126 doesn't help there, but echo active > /sys/class/block/md126/md/array_state does. I forgot to mention that I'm running 2.6.36.5 with mdadm 3.1.4. -- Regards, Laurent Pinchart -- 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
