On 02/08/18 10:13, Jonathan Milton wrote: > Hi, > > Overnight my server had problems with its RAID5 (xfs corrupt inodes), on > reboot the raid comes up inactive. > > * Smarttools suggest disks (3x2TB) are healthy. I have powered down and > checked all the SATA leads are still plugged correctly. > > * MDADM is unable to assembled to raid from 1 drive: > # mdadm --assemble /dev/md0 /dev/sda1 /dev/sdc1 /dev/sdd1 > mdadm: /dev/md0 assembled from 1 drive - not enough to start the array. > > * Event counts are well off on one drive ( 290391/182871/290391) Not good. > > * SCT Error Recovery Control was disabled on all drives prior to this > failure but I have since modified the boot scripts to set to 7s as per > the wiki (no improvement) > > I am considering whether to try --force and would like advice from > experts first > NOT WITHOUT A BACKUP! > > Thanks in advance > That "only one drive" bothers me. Have you got any spare drives? Have you any spare SATA ports to upgrade to raid-6? I'd ddrescue the two drives with the highest count (is that sda and sdd?), then force assemble the copies. That stands a good chance of succeeding. If that works, you can add back the third drive to recover your raid-5 - keeping the original two as a temporary backup. If you can't get spare drives, overlay the two good drives then see if a force gets you a working array. If it does, then you can try it without the overlay, but not having a backup increases the risk ... Then add one of the original drives back to convert to raid-6. The event counts make me suspect the middle drive got booted long ago for some reason, then you've had a hiccup that booted a second drive. Quite likely if you didn't have ERC enabled. So it does look like an easy fix but because you've effectively got a broken raid-0 at present, the risk to your data from any further problem is HIGH. Read https://raid.wiki.kernel.org/index.php/Linux_Raid#When_Things_Go_Wrogn If you don't have any spare SATA ports, go and buy something like https://www.amazon.co.uk/dp/B00952N2DQ/ref=twister_B01DUJJZ8U?_encoding=UTF8&th=1 You want a card with one SATA *and* one eSATA - beware - I think most of these have a jumper to switch between SATA *or* eSATA so you'll want a card that claims two of each - it will only actually drive two sata devices so configure one port for SATA for your raid-6, and one for eSATA so you can temporarily add external disks ... https://www.amazon.co.uk/iDsonix-SuperSpeed-Docking-Station-Free-Black/dp/B00L3W0F40/ref=sr_1_1?ie=UTF8&qid=1529780418&sr=8-1&keywords=eSATA%2Bdisk%2Bdocking%2Bstation&th=1 Not sure whether you can connect this with an eSATA port-multiplier cable - do NOT run raid over the USB connection !!! Cheers, Wol -- 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
