R610 Memory - Installed Capacity for OS seems low

Question

Hi,

Recently we purchased a PE R610 with 196 GB of memory installed by Dell. The Dell OpenManage Server Administrator shows the 12 DIMMs registering properly and in the section titled "Total Memory Array(s)" Installed Capacity and Maximum Capacity each indicate 196 GB, but "Installed Capacity Available to the OS" shows 131 GB.

Is this related to the "Memory Operating Mode Configuration" running as "Spare"? I don't see anything in the "R610 Systems Hardware Owner’s Manual" about this mode configuration.

The plan is for this server to run W2008-R2SP1.

Is there a good reason not to have more memory available to the OS? How do I increase it?

Thanks,

Ben

DELL-Chris H · Accepted Answer

Ben, In the BIOS, what is the Memory Mode set to? It sounds like it is set to Advanced ECC. Please change that to Optimizer and let me know if all the memory is then listed. Let me know what you see.

theflash1932 · Answer

With Advanced ECC or Mirroring, the last memory channel sockets are not usable by the OS (8x16GB=128 (-ish, plus some bit-math=131)), as they are used to manage the redundancy.  If you want the full 196GB, you must set Memory to Optimized.  If you want some memory redundancy, then leave as is and live with less usable memory.

theflash1932 · Answer

Also keep in mind the memory limits for 2008R2:

2008R2 HPC is limited to 128GB (roughly what you are showing).

Only 2008R2 Datacenter or Enterprise can use more than 128GB.

Standard, Web, and Foundation are limited to substantially less than what you say it shows, so I'm assuming you are not using any of these versions.

BenB36 · Answer

Yes, I am running Data Center version of 08R2SP1.

Checking the BIOS settings, the memory mode was set to "Spare Mode" changing it to Optimizer did the trick - 192 GB is now available to the OS!

Thanks!

Ben

PowerEdge Hardware General

R610 Memory - Installed Capacity for OS seems low

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