On 2014-05-10, CS_DBA <cs_dba at consistentstate.com> wrote: > > If we loose a drive in a raid 10 array (mdadm software raid) what are > the steps needed to correctly do the following: > - identify which physical drive it is This is controller dependent. Some support blinking the drive light to identify it, others do not. If yours does not you need to jury-rig something (e.g., either physically label the drive slot/drive, or send some dummy data to the drive to get it to blink). > - replace the drive The md part is easy. If md hasn't failed the drive already, then you need to do that first: mdadm /dev/mdN --fail /dev/sdXX Then remove it from the array: mdadm /dev/mdN --remove /dev/sdXX The physical part is, again, hardware dependent. > - add the new drive to the array and force it to re-sync Again, physical part hardware dependent. Once the kernel knows about your new drive, this should work (partition the drive if needed beforehand): mdadm /dev/mdN --add /dev/sdYY There may be extra parameters for replacing a failed RAID10 drive, but I suspect that md already knows the needed parameters, so just adding the drive should kick off a rebuild of the failed member. -- kkeller at wombat.san-francisco.ca.us