At B&R 9.5 update 4a we had quite some issues with backup copy jobs failing with the message:
Error: Socket has been forcibly closed. Failed to recover connection.
Maximum retry count reached (5 out of 5)
Especially on the larger VM's (1 - 1.5 TB) the jobs would fail about 5 of the 7 times per week.
We reported this at Veaam support. The NAS repository used for the backup copy is a Synology RS 812+ running the Veeam Linux Agent. We know that this is not a preferable setup but it has served as well for years.
Support reported that from the logs it appeared the system was running out of RAM so we upgraded from 3GB to 5GB. This helped a bit, the errors were less frequenct but still about 3 days per week. (Daily backup copy jobs)
Running an extra job to the same type of NAS but using the Windows agent worked fine.
About two weeks ago we upgraded from update 4a to 4b and the issues have completely disappeared. Seems that one of the bugs that was fixed in the update was one in the Linux agent that had hit us. We're very happy about that.
So anyone having backup copies failing with this error, try the 9.5 4b update!
Cheers,
Alex