Multiple server docker instances, uniqueness of snapshots

I’d like to run one kopia server docker instance for each of my linux servers, whose files i intend to back up. All of them will point to the same S3 bucket.

My question is, what information is used to identify the uniqueness of a snapshot?
Is it the snapshot path + kopia user + docker instance hostname?

Which means if the docker snapshot path is /data in all docker instances, then I need to ensure the user + hostname are unique across the docker instances to avoid collisions?

Hi, i have a similar setup, just with windows clients instead of servers. However, I have just one docker instance which is running in server mode. Each client has a separat account.

As to your question: The hostname and potentially the user needs to be different for each client. The path can be same.

I’ve ran into issues when I was using the same hostname for all clients. Reason was, that kopia thought that all paths existed in tried to manage these as well on the host.

A different hostname + user should do it.


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Thanks! What you say makes sense.

Out of curiosity, could you describe your setup a bit more? If there is only one docker instance running in server mode, how do you handle automatic snapshotting on the windows clients?
Are the clients running KopiaUI and they take care of auto running when needed?

The reason i’m thinking of running multiple docker instances in server mode is that it auto-scheduling comes out of the box via the web ui.

Whereas if I used regular clients connecting to the server, i believe i’d have to handle that myself somehow (e.g. via custom cron).


indeed. Each client is running kopiaUI for windows and connects to the server. The clients have their own policies and snapshot according to their plan. As I am using server mode, each client cannot see and access the snapshots of other clients. Only the server reachable by the web-ui can access all snapshots of all clients.

If you want to backup your servers, you can also do it with kopia natively. However, i guess you would need to take care of start-stop scripts (on startup). I am not sure if you have to take care of cron-jobs. I think there is a post about that here in the forum.


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That’s what i like about running multiple server instances in docker.

  • docker-compose takes care of restarting the instance when rebooting
  • kopia server has a built-in scheduler that auto-runs the backup jobs. all the UI seems limiting, allowing only a very small granularity for auto-running (up to 12 hours)
  • if one server is down, the other servers can still have their backups working