Syncoid option for 2 production servers and 1 backup server

OpenZFS Sanoid
1

Hello,

I have 3 servers; A,B and C. Server A and B are production servers while C is a purely a backup server. Both A and B have sanoid running on them. Every night server A and B transfer their datasets to each other.

The syncoid commands are always initiated from server A like so

#syncoid -r tank/datasetA root@serverB:tank/backupA/datasetA
#syncoid -r root@serverB:tank/datasetB tank:/backupB/datasetB

The backups are running fine. Now i want to introduce a third server C to backup both server A and B. I guess we dont need sanoid on server C. However as before i want to initiate syncoid from server A. Should i be using --no-sync-snap like so:

#syncoid -r tank/datasetA --no-sync-snap --delete-target-snapshots root@serverC:tank/backupA/datasetA
#syncoid -r tank:/backupB/datasetB --no-sync-snap --delete-target-snapshots root@serverC:tank/backupB/datasetB

I am not sure if i need to use ‘–identifier’ option. My aim is to not to get any warnings of unknown datasets when doing these syncoid transfers.

2

You need to either use no-sync-snap, or write a simple script that looks for “foreign” sync snapshots and destroys them. Otherwise, sync snapshots for A–>B will pile up on C (and etc) until you run out of space.

You do need sanoid on C, because otherwise no snapshots will ever be destroyed, no matter how old. Be sure to use the backup or hotspare templates for backup targets, not the production template–and that applies to backups of A that live on B, and vice versa, as well as the stuff on C!

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