Truenas to backblaze sync and high usage

I make with 1 xcp-ng and 1 proxmox host backups to a truenas system this backups will be kept for 2 weeks. 2x a week this data get synced to backblaze with a cloud replication task. Truenas says these 2 datastores consume around 200GB together. Backblaze says there is 1296GB of data in the bucket. The transfer method used in the replication task is SYNC. So I thought that backups that are removed from the datastores will also be removed from the backblaze bucket. But it looks like this is not happening.

Can someone explain to why there is much more data in the backblaze bucket than in my datastore on truenas? Is this normal behaviour or am I doing something wrong?

Check your versions of the files in Backblaze and the retention policies in Backblaze.

I see for most files there are 2 versions. 1 is the full size, the other only a few kb.

I have now set the file lifetime to only the last version. Maybe this will help.

The files are all encrypted so I can not see which file consumes the most.

Still I don’t get it how this is happening. There are a maximum of 8 backups on truenas. When the 9th will be created the oldest get removed. I thought that the syncing nature of cloud replication will also remove this oldest backup at backblaze bucket. Or am I thinking wrong?

The depends on the Backblaze versioning which should fix the issue.