DIMM module configuration compatibility

[Karl Breiner]

I have a UCS blade model UCSB-B200-M4-CH.

I have 16gb DIMM (PN UCS-MR-1X162RU-A) with quantity 8, and 32gb DIMM (UCS-MR-1X322RU-A) with quantity 16.  This should total 640gb.

Is this configuration possible?  If so, which slots should the modules go into?  During post, I see 'configuring memory' and it stalls. 

[Mohammed Majid Hussain · Accepted solution]

We can mix DIMM's with different capacities

When mixing DIMMs of different densities (capacities), the highest density DIMM goes in slot 1 then in descending density.

Please look at the DIMM Mixing Rules in following link (search for DIMM Population Rules) 

http://www.cisco.com/c/en/us/td/docs/unified_computing/ucs/hw/blade-servers/B200M4/B200M4_chapter_011.html#ID743

Also, give "DIMMs and Channels" a look in:

http://www.cisco.com/c/en/us/td/docs/unified_computing/ucs/hw/blade-servers/B200M4/B200M4_chapter_011.html#ID743

-Majid

[Karl Breiner]

I actually found that guide prior to your response but I still can't get the blade to POST.

Do I have this correct?

A1 32GB
B1 32GB
C1 32GB
D1 32GB
A2 32GB
B2 32GB
C2 32GB
D2 32GB
A3 16GB
B3 16GB
C3 16GB
D3 16GB

E1 32GB
F1 32GB
G1 32GB
H1 32GB
E2 32GB
F2 32GB
G2 32GB
H2 32GB
E3 16GB
F3 16GB
G3 16GB
H3 16GB

[Kirk J]

Your population order looks correct.  You have valid PIDs for this server, they are both RDIMMs, dual rank.  If the server is still hanging at post during checking config/mem test, then you may want to remove the 16 GB DIMMs, so this is a 2DPC config and see if it boots.  It may be possible that you have a problem DIMM, or one isn't seated all the way.  See if you can start to isolate which bank and channel has a problem DIMM.

You may need to open a TAC case as they can review the blade logs to see if a particular DIMM isn't passing the BIST/poweron test.

Thanks,

Kirk...

[Karl Breiner]

The server will boot with only the 32gb DIMMs present.  It fails when adding the 16gb, and I've tried swapping several 16gb DIMMs, so I know it's not just single DIMM failure.

I've had a TAC case open for 2 days and they can't figure it out.  The module IS listed in the Compatibility Catalog.

The only clues are the 16gb modules displaying "unspecified" in the inventory and "operState: disabled" in Faults.