I'm running MergeFS + SnapRAID. I am trying to expand the storage in my instance from 3TB (of which 1TB is parity) to 8TB (with 4TB as parity, planning to add more data drives once the mail arives).
I have drives /dev/sda through /dev/sdh:
/dev/sdc - is my OS drive - 128GB in size
/dev/sdd - exiting data drive - 1TB
/dev/sdh - existing data drive - 1TB
/dev/sdf - existing parity drive - 1TB
/dev/sda - new parity drive - 2TB
/dev/sdb - new parity drive - 2TB
/dev/sde - new data drive - 2TB
/dev/sdg - new data drive - 2TB
Right now, /dev/sdd, /dev/sdh and /dev/sdf are plugged in via USB and the MergerFS is created on it. My merge pool path is /srv/mergerfs/mergerPOOL/. I want to be able to keep the path and the data in that path as is without making any changes to the structure while just replacing the drives. After everything is done I want to be able to remove /dev/sdd, /dev/sdh and /dev/sdf and not be worried about anything not working or if I'm overdoing this and there is a better/simpler/secure-er way.
My plan is the following, and I would like someone to evaluate my plan for me.
1. Stop all my running containers and services. Backup some important data to an external drive.
2. Add New Parity Drives (/dev/sdb and /dev/sda) to SnapRAID's existing array. Parity numbers will be 2 and 3 respectively(?)
3. Add New Data Drives (/dev/sde and /dev/sdg) to MergerFS's exiting pool
4. Run SnapRAID Sync and verify the sync by running a SnapRAID Check (to make sure I have my old parity drive up to date)
5. Remove old parity drives from Snapraid's Array
7. Remove old data drives from MergerFS Pool
8. Move data from existing data drives to new data drives with:
rsync -avh --progress /srv/uuid-of-sdd/ srv/uuid-of-sde/
rsync -avh --progress /srv/uuid-of-sdh/ /srv/uuid-of-sdg/
9. Restart MergerFS
10. Change parity numbers to 1 and 2. needed(?)
11. Run SnapRAID Sync and verify the sync by running a SnapRAID Check
12. If all goes well start up all my services and unmount all my old 1TB drives which are plugged in via USB
13. Once my mail arrives with 3 more 2TB drives, simply expand MergerFS Pool