no data transfer possible + system hangs/freeze on WebUI and SSH

[MatthiasDB]

System:
AMD EPYC 7252
256GB RAM
Broadcom (LSI/Avago) HBA 9300-8e
22x 10TB SAS HDD

Software:
TrueNAS 12..0-U6.1
1 pool with 4 vdevs raid-z1

Problem:
since around 3 days, I cannnot copy any data to the ZFS Pool. I tried SMB and SCP nothing works.
I can browse the SMB Share, but if I start a filecopy, it stops after some GB (maybe after caching). I even tried to copy a file per scp - same behavior.
Also the system hangs/freeze somtimes. Then no access to webUI is possible and even an ls on ssh console hangs for minutes.
In the console I see some python Errors.

I tried reboot, update TrueNAS to the latest version (12.0-U6.1), nothing help
the /var/log/messages logfile doesn't show anything related

Has anyone any idea what I can do?

thanks
Matthias

 

[MatthiasDB]

I forgot one important detail.
The Pool has deduplication enabled, but one of the dataset I'm trying to write to, has dedup disabled.

Reading from this pool works.
On another pool with 5 disks (1 vdev, raid-z1) there are no problems to copy files to.

So it has to do with this specific Pool