Kernel error kernel:[360783.353677]

[Arcesilaus]

I did, and I also disabled all ACPI functions in the machine's BIOS.
Furthermore, I've replaced the power supply yesterday and moved the SSD to the Areca Controller, to see if the onboard SATA controller might be the problem.

By the way -just for the information of others-, after moving the disk from the onboard controller to the Areca controller, another reboot was required before I could reconnect the Volume to the iSCSI target, but it worked surprisingly well.

Unfortunately, this morning the machine went down again, and not being home, I haven't had a chance to reset the machine and look at the logs.
Tonight, I'll bring the machine back up, check the ACPI settings, examine the log and post my findings here.

Are there any logs beside the dmesg.2 and critial_errors.log (so far: this was always empty) files that I should examine?

P.s. I found two other forum threads in which similar behavior is mentioned: here and here. With reference to the first, recalling when the freezes started, I think it was after upgrading above v6 update 90.
Unfortunately, in neither thread a final outcome is reported.