synchronize btrfs snapshots over a unreliable, slow connection

[" " <Cedric.dewijs@eclipso.eu>]

­I have a master NAS that makes one read only snapshot of my data per day. I want to transfer these snapshots to a slave NAS over a slow, unreliable internet connection. (it's a cheap provider). This rules out a "btrfs send -> ssh -> btrfs receive" construction, as that can't be resumed.

Therefore I want to use rsync to synchronize the snapshots on the master NAS to the slave NAS.

My thirst thought is something like this:
1) create a read-only snapshot on the master NAS:
btrfs subvolume snapshot -r /mnt/nas/storage /mnt/nas/storage_snapshots/storage-$(date +%Y_%m_%d-%H%m)
2) send that data to the slave NAS like this:
rsync --partial -var --compress --bwlimit=500KB -e "ssh -i ~/slave-nas.key" /mnt/nas/storage_snapshots/storage-$(date +%Y_%m_%d-%H%m) cedric@123.123.123.123/nas/storage
3) Restart rsync until all data is copied (by checking the error code of rsync, is it's 0 then all data has been transferred)
4) Create the read-only snapshot on the slave NAS with the same name as in step 1.

Does somebody already has a script that does this?
Is there a problem with this approach that I have not yet considered?­

---

Take your mailboxes with you. Free, fast and secure Mail & Cloud: https://www.eclipso.eu - Time to change!