Proliant ML110 G5 and 2 RAM Kits of different make not starting

[Chaironea]

Hi,

I searched the posts and did not find anything about this topic.

I have an ML110 G5 with 2 GB of RAM (2x1 GB Kit) and have bought another Kit of the same size but different make, yet also labelled HP. The old kit has double sided RAM, the new one is single sided. Both are the prescribed 6400E (DDR2-800) type.

The server will now start with both kits installed individually, but not with all 4 of them. I tried different positions (kit one on DIMM 1A and 3B, kit two 0n DIMM 2A and 4B; kit one on DIMM 1A and 2A, kit two on DIMM 3B and 4B), but to no avail.

So my question is: has anyone made the same experience and found a solution? Is it that I need two identical kits, or is the problem that the kits must either be both single sided or double sided?

I am well aware that memory configuration is a delicate issue and that even configurations running on one machine must not necessary do so on another identical one, so I am not really to surprised to run into this problem but am of course a bit disappointed that it was not straightforward this time.

(Background is that I do the administration at my wife's school and have bought another identical server very cheap both as a backup and also to be able to try configuration changes without impairing the actual running system. Yet the server needs 4 GB of RAM as one of the processes requires between 1 and 1.8 GB of RAM alone.)

[RbBsmn]

From the quickspecs:

HP ProLiant ML110 G5 Models
NOTE: Memory configurations listed do not apply to "Factory Integrated Models".
Standard Memory
SATA Models:
1 GB of PC2-6400 DDR2 SDRAM running at 800MHz with ECC capabilities memory installed.
Standard Memory Plus Optional Memory
Up to 6 GB memory is available with the optional installation of 2 x 2 GB + 2 x 1 GB PC2-6400 un-buffered ECC DDR2 SDRAM
DIMM Memory kits.
Standard Memory Replaced with Optional Memory
Up to 8GB of memory is available with the removal of the standard 1 GB of memory and the optional installation of 4x 2 GB PC2-
6400 un-buffered ECC DDR2 SDRAM DIMM Memory kits.
NOTE: The below chart does not represent all possible memory configurations.
NOTE: For best performance, it is recommended that customer installs memory in identical pairs (Slots 1 and 3 are interleaving
pair. Slots 2 and 4 are interleaving pair).
Memory Slot
1 2 3 4
Standard 1 GB 1 GB Empty Empty Empty
Optional 6 GB 1 GB 2 GB 1 GB 2 GB
Maximum 8 GB 2 GB 2 GB 2 GB 2 GB
Following are memory options available from HP:
HP Memory HP 2GB (1x2GB) Dual Rank PC2-6400 (DDR2-800) Unbuffered Memory Kit 450260-B21
HP 1GB (1x1GB) Dual Rank PC2-6400 (DDR2-800) Unbuffered Memory Kit 450259-B21

Seems for this server there is only 1 supported 1GB module available.
Guess that would be the problem.

Normally (on newer servers) you can mix single rank and dual rank (and quad rank for that matter) as long as you keep the lowest ranks in the first banks that need to be populated.
However it seems on this older server this was not yet an (supported) configuration option.

[Chaironea]

Thanks,

that was something I had not thought of. I'll have a look at the other server. It has 4 GB or RAM, and maybe it is installed in 2 x 2 GB instead of 4 x 1 GB as I intended to on the new one. Then I ought to have considered that before purchasing additional bars.

[Chaironea · Accepted solution]

Ok, a strange story just happened.

Inspired by the post of RbBsmn I inserted one single-sided DIMM into 1A and one double-sided one into 3B. As expected, the machine would not start with two different DIMMs set for Interleaving.

Inserting the same DIMMs into 1A and 2A made the machine start in non-Interleaving mode. So now it was settled: The machine CAN take two different kinds of modules in non-Interleaving mode.

I now became courious and inserted the appropriate DIMM into slot 3B and the machine booted with 3 GB.

Against all reason, having tried that configuration before, I now inserted the last DIMM into slot 4B. Of course, that would now result in not booting up, wouldn't it? It only makes sense.

But: sense is not always where memory configuration takes place. The machine did now strangely but luckily boot up with the four DIMMs inserted as two Interleaving pairs.

I have no idea, why this is the case, as I have tried different configurations of pairs a couple of times before just to be sure I did not miss out anything from dust to not properly engaged DIMMs. But I have learned to accept that strange things happen in computer technology and will now cross my fingers each time while booting that machine, hoping it does not remember it has rejected its current configuration before.