[CentOS] DIMM problem

Thu Apr 25 20:49:38 UTC 2013
Nathan Duehr <denverpilot at me.com>

It won't help you on troubleshooting which RAM module is bad, but dmidecode may be helpful in figuring out how many slots/sticks you have and what's populated and not populated.

Typically if the lights are not on on that display, the RAM is tossing ECC errors or similar, but not fully failing.  I have a bunch of G6 and G7 machines, but no G5 to look at to assist you.

The G8 machines should have been given a different model number, they're completely different beasts (and there's a number of things I'm learning to dislike about them, honestly).

I had a G7 that kept setting the RAM lights as if it had a RAM problem, so the server support vendor visited more than once.  The real problem was a failing CPU.  I mention it, because I've seen RAM problems that really weren't and were misdiagnosed by the relatively crude monitoring built into those motherboards, more than once.  I've also run the HP diagnostics for a full day, and had it find absolutely nothing, and have the lights come back on 5 minutes after firing the on-disk OS back up.  Same thing with other tools like memtest86.

Swap the RAM out completely.  If that doesn't fix it, swap the associated processor out.  I've never seen any other hardware in those pizza box machines be the cause of the RAM problems you're seeing.

If you can't swap it completely, swap sides and move it to the other side.  See if it follows the RAM or the slots.  Often it follows the slots, and the problem is the CPU which talks to that "half" of the motherboard, not the RAM.

At least that's what I've seen... YMMV.