Table of Contents
Memory test hung after upgrade to 64GB RAM
Update: The problem was fixed as stated in Memory test hung after upgrade to 64GB RAM (Follow-up)
Took many hours to troubleshoot RAM test hanging issue.
Testing software
MemTest86
The test was hung at 86% during pass 1.
Memtest86+
The bootable USB created was not bootable.
Ubuntu Live CD
The testing was hung just started.
Posible issue
Hardware issue
Should not be RAM issue, tested them by separating them into two sets with 32GB each, using MemTest86, both sets can pass.
Maybe slot issue
The RAM must be in slots in correct order, otherwise, the RAM can not be detected. In fact, this mother board is quite sensitive to the RAM position.
Maybe RAM hot
The RAMs could be too hot, the newly added RAMs make the gabs between RAMs are too small, the fans are also not strong enough, this could cause high temperature. I tried to adjust the fan speed by using the controls on casing, but not effective.
But RAM should be able to take high temperature, and the type of RAM I bought has cooling case.
Software issue
Maybe conflict with VGA
The max RAM size that MemTest86 can support, is 64GB, which means it could have bug too. On the other hand, the hunging shows nothing on the screen, black screen, but keyboard light was still responsive, and the VGA light on mother board was turned on. Maybe the software wrote the area that video card used caused such issue.
Conclusion
Although the testing was hung, I decided still use them.
In order to use them fully in TrueNAS, I adjusted the zfs_arc_max to 60GB, and run two VMs, one Windows at 4GB, one ubuntu at 6GB, till the memory free less than 4GB.
Result
The TrueNAS looks working fine, although restarted once, log didn't show the cause related to memory, and there was no memory issue in dmesg monitoring screen.