Moar RAID Win

Had to upgrade my storage over the past week and decided to see just how good Linux software raid (mdadm) and SATA hot plugging were these days. The current setup was a five disk array with two 1TB and three 750GB drives attached to an ASUS M3A76-CM motherboard in AHCI mode. My first issue was that all five drives were attached internally so access would require mucking about in the case to replace the three disks so I dug around and ended up purchasing a Supermicro CSE-M35T-1B so I would be able to swap the disks out easily.

After getting the original drives shifted into the new rack, it was as easy as 1-2-3(ish) to replace the drives (with the filesystem live):

1. mdadm /dev/md1 --fail $PARTITION --remove $PARTITION
2. Replace disk, create partition
3. mdadm /dev/md1 --add $PARTITION, resync

Each resync after the replacement took 3-4 hrs and the fan in the rack kept the disks no warmer than 32C. After the final disk was done and synced, I expanded the array to include the new space:

mdadm --grow /dev/md1 --size=max

Then let lvm know the new space was usable:

pvresize /dev/md1

And ran vgdisplay to see my extra ~940GB.

Gawd it’s nice when stuff Just Works.