Laurentiu Coica wrote: <Long, detailed technical demo snipped> Thanks VERY much, Laurentiu, for all the work you went through! I must apologise for not including more details of what I did. There are some differences between what I did and what you simulated which makes your conclusion not quite applicable. 1) /mnt/deanm (using your names) was unmounted when I stopped the array. (This is probably minor.) 2) I did _not_ remove devices from the RAID1; I stopped the RAID with "mdadm --stop <device>" 3) The LVM was not de-activated first (which is what caused the problem). The "live" device on which the LV sat went dead. There were a few other minor differences not worth mentioning. But in any case, thanks to your post, I was motivated to experiment with a toy array on a couple of small identically sized partitions and discovered the solution: I was able to assemble the stopped toy array on _another_ md device (/dev/md2). It would not let me assemble on /dev/md1 for some reason. Then I was used: (I called my experimental VG "vg_exp") # vgmknodes --refresh vg_exp /dev/md1: read failed after 0 of 4096 at 0: Input/output error /dev/vg_exp/lv_exp: read failed after 0 of 4096 at 2092892160: Input/output error /dev/vg_exp/lv_exp: read failed after 0 of 4096 at 2092949504: Input/output error /dev/vg_exp/lv_exp: read failed after 0 of 4096 at 0: Input/output error /dev/vg_exp/lv_exp: read failed after 0 of 4096 at 4096: Input/output error /dev/md1: read failed after 0 of 4096 at 2096234496: Input/output error /dev/md1: read failed after 0 of 4096 at 2096345088: Input/output error /dev/md1: read failed after 0 of 4096 at 4096: Input/output error # vgmknodes --refresh vg_exp Note that the first invocation gives a boatload of I/O errors just as I have been seeing with my 2TB RAID. But the 2nd invocation doesn't. Magically the system figured out that the RAID1 was now on /dev/md2 and properly associated the VG and LV with that device (which, of course, had the physical extents of it, /dev/md1 being stopped. Also /dev/md1 disappeared from /dev (a side benefit). I can mount /dev/vg_exp/lv_exp onto /mnt/exp and see what I wrote there before. Thanks again for your post, which motivated me to spend a couple hours "experimenting". My data has been saved! Dean -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
