Running Sandstorm From a Raid 1 Drive Array

In my quest to back slowly towards the exits from total reliance on Google’s infrastructure, I’ve managed to stand up an instance of Sandstorm on a small ZimaBoard. This has been successful; one thing I was very concerned about was storage reliability because I know if I’m rotating away from someone else’s Cloud, it’s up to me whether I lose data if these drives break. To that end, I put both two Seagate 2TB drives in a CENMATE 2-drive SATA enclosure and went about setting up a RAID-1.

The process is pretty straightforward!

1. Install mdadm, which can manage multiple disk fusion.
2. After plugging in the drives, find what the device names are with sudo fdisk -l. Mine happened to be /dev/sda and /dev/sdb.
3. Fuse them: sudo mdadm --create /dev/md/store /dev/sda /dev/sdb --level=1 --raid-devices=2. This created /dev/md/store, which symlinks to /dev/md/127.
4. Now that the drives are fused, they need a filesystem. sudo mkfs -t ext4 /dev/md/store
5. Now, we give them a place to live. sudo mkdir /mnt/store && sudo mount --source /dev/md/store --target /mnt/store.
6. Finally, we want to make sure they mount at boot. a. Find the UUID with lsblk -o NAME,FSTYPE,UUID. md127 shows up with file system type ext4, under an sda and sdb with type linux_raid_member. The UUID is listed here, and they are the same. b. Back up the /etc/fstab file, then edit it to add the line UUID=SOME-UUID /mnt/store ext4 defaults 0 0.

With all that out of the way, the only remaining work is to move Sandstorm over.

1. Stop sandstorm. sudo sysctl stop sandstorm.service
2. sudo cp -R /opt/sandstorm /mnt/store/sandstorm
3. sudo mv /opt/sandstorm /opt/sandstorm.old (just in case; can delete later)
4. sudo ln -s /mnt/store/sandstorm /opt/sandstorm
5. sudo sysctl start sandstorm.service

And we’re good! Service startup chases through the symlink and everything’s all wired up.