Hotswap remove disk

backup partition table

sfdisk -d /dev/sdb > partitions.sdb

Mark faulty and remove the drive to replace from the array

mdadm -f /dev/md0 /dev/sdb

Look up the Host, Channel, ID and Lun of the drive to replace, by looking in

cat /proc/scsi/scsi

Remove the drive from the bus:

echo "scsi remove-single-device 0 0 2 0" > /proc/scsi/scsi

Verify that the drive has been correctly removed, by looking in

cat /proc/scsi/scsi

Unplug the drive from your SCA bay, and insert a new drive

(normally done by udev) Add the new drive to the bus

echo "scsi add-single-device 0 0 2 0" > /proc/scsi/scsi

Restore partition table

sfdisk /dev/sdb < partitions.sdb

Add the drive to your array

mdadm -a /dev/md0 /dev/sdb