On 2014-05-10, Dennis Jacobfeuerborn <dennisml at conversis.de> wrote: > > This can also be inverted especially if you cannot send data to the > drive anymore because it dies completely: Create lots of disk i/o with a > command like "grep -nri test /usr" and all drives except the broken one > should show activity. That's certainly a good idea. If you have multiple arrays you'd need to send that IO to each array at mostly the same time, but with only one array it's less difficult. I think the most challenging scenario would be if the array has multiple spares--if the array rebuilds before you can look at it, then you have to generate IO on the array and on the drive(s) that are still spares. If you have no active spares (either you started with none, or you had one and it's been used to replace the dead drive), one way to make IO is to start a check of the md array (e.g., echo check > /sys/block/mdN/md/sync_action ). The drive that doesn't blink is the dead one. > Another way is to write down the serial numbers of the disks, the slots > you put the disks in and then use hdparm -I /dev/sdX to find which > device shows which serial number. That way once sdX dies you can check > the list to find which slot the disk for the failed device was put in. Physical labelling in this way (or some other way) is still the best solution, as long as you keep the list up to date (and don't screw up the list, of course). But it's definitely good to have multiple methods in your toolbox--for example, you might try the IO trick, then cross-check it against your physical labels. Better to take some extra time verifying which drive is dead than to pull the wrong one! --keith -- kkeller at wombat.san-francisco.ca.us