TerraMaster Forum

I encountered a critical bug on TOS6 (Terramaster). Can anyone tell me what it is?
I have a Terramaster F6-424 Max. 2 volumes: TRAID (4 x 6 TB), btrfs, and RAID1 (2 x 4 TB), btrfs. The latest version is currently 6.0.783. (I don't know if this matters, but the BIOS version is "default" - 5.26).
Twice a day (around 12:00 and 24:00), the btrfs-transact job starts (and then btrfs-cleaner). At this point, the NAS starts to slow down significantly (clearly visible in the GUI). But the bug itself is different: this process locks files from VirtualBox, and the virtual machines crash with "Buffer I/O error on device sda" errors. Only stopping and restarting the virtual machines helps. (I described this here - viewtopic.php?t=9194)
What else? This hasn't happened before. It seems this bug arose after upgrading to 6.0.783.
Any ideas on how to fix this?
So far, I see two possible solutions:
1. Roll back to one of the previous versions of TOS6
2. Try migrating VirtualBox from a TRAID volume to a RAID1 volume

The btrfs-transact process is responsible for submitting write operations. It packages new write operation metadata into transactions and commits them to the disk.
The btrfs-cleaner process is used to clean up old transactions and reclaim space. After transactions are submitted, it cleans up unnecessary metadata, references, and unused space in the background.

It should be noted that these two processes did not appear after upgrading to version 6.0.783, so they are not related to the TOS version. From your previously posted message, it is clear that there are I/O errors on the hard disk sda. It is recommended that you replace the hard disk, and then check if the btrfs-transact and btrfs-cleaner processes are still running. If these two processes are still running, please immediately stop all read and write operations and wait patiently for the processes to complete.

No. These are not disk errors, I checked them.
But I solved this problem by disabling quotas: