@poddingue said:
While you experiment, do the failing VMs have something in common? The same source SR, for example, or a mirror target keeping a different retention than the source.
There are two backup jobs that are failing. One from Ark (local) to Synology, and one from Ark to S3. It seems to be the same VMs failing each night, but interestingly, there are some that fail to Synology but succeed to S3 and vice-versa. There are 9 VMs that fail for both. They do not all share the same SR. The backups on Ark are coming from several delta jobs that run daily, weekly, and monthly. Retention are different for all those.