unreleased file from the memory

[mikok]

Hi, I am going to report an unreleased file from the memory by FreeFileSync 11.8 and 11.9.
I run a night Windows backup job on Windows server 2019 1809 build 17763.1823.
The backup data is mirrored from E:\ to the NAS by FreeFileSync batch, the log attached.
The NAS is attached via iSCSI and mapped as H:\.
Today, many hours after the mirror job finished, using RamMap, I can see abnormal RAM consumption, which is caused by one of the mirrored 96GB file. In the RamMap / File Summary / Modified I see 16GB.

If I run the Process Explorer and list all File handle, the file 5c88c*.vhdx is not listed.
The file has been released from the RAM just after I deleted it in explorer from its H:\ location.

I upgraded to FreeFileSync 11.9 and run the FreeFileSync mirror batch again. I captured the following state after few minutes: In the RamMap / File Summary / Modified I see 5GB.

This I could see when the mirror job had been running for about an hour. The server had used up most of its memory. The file being copied takes 15GB.

The server RAM was used up 90% and I was looking forward to see the server crash live. The RAM usage started to go down slowly. The job finished after another half an hour but the RAM was not released completely. 20 minutes later I took another screenshot: The file being copied takes 15GB.

This is the state 3 hours late I can see 15GB of RAM is blocked.

I pay attention to it, because I have found my server crashed twice during last month. I was called because the server was not responsive to users in the morning. I was not able to finish the server log on. I could see just blank desktop after I entered the password. I could just run task manager with CtrlAltDel and see the high memory usage. Even though I could log on the virtual machine running on the server, shut it down correctly and release 12GB of RAM this way, the host server was still unresponsive. The only way was a reboot. Even the shutdown got stuck after few seconds and I had to hard reset the server. After the reboot I could not find any error in the event logs or anything helpful to sort it out.

I have to use the built-in robocopy instead. Just 0,5GB of RAM is used at most.