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August 4th, 2016 07:00

Memory Mapping

Hello,

I have 2 servers PowerEdge R720xd used as Hyper-V servers, let's call them HV1 and HV2.

HV1 has 32GB of memory, 4x8GB and HV2 has 48GB of memory 12x4GB.

Each server has 2x12 slots of memory, 12 per CPU.

On HV1, used slots are 2-4 and 14-16 (or A2-A4 and B2-B4)

On HV2, used slots are 1-2-3-4-6-8 and 13-14-15-16-18-20 (or A1-A2-A3-A4-A6-A8 and B1-B2-B3-B4-B6-B8)

I will add soon 4x8GB of memory on each server.

First question : Do you think actual slots are the best mapping ?

Second question : which are the best slots where to add my 4 new 8GB ?

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6.2K Posts

August 4th, 2016 11:00

Hello

First question : Do you think actual slots are the best mapping ?
On HV1, used slots are 2-4 and 14-16 (or A2-A4 and B2-B4)

HV1 is not populated correctly. I'm not sure why you skipped slot 1. The memory should be in {1,2}.

On HV2, used slots are 1-2-3-4-6-8 and 13-14-15-16-18-20 (or A1-A2-A3-A4-A6-A8 and B1-B2-B3-B4-B6-B8)

HV2 is not populated correctly. The memory should be in {1,2,3,4} and {5,6} on both lanes. The A and be lanes must have identical population of memory.

Second question : which are the best slots where to add my 4 new 8GB ?

I assume they are going into HV1. If the new DIMMs are identical in specifications to the memory currently installed in HV1 then it should be {1,2,3,4} on each lane. If the memory is different in specifications then population should be {1,2} and {5,6}.

Thanks

4 Posts

August 5th, 2016 01:00

There will be 4x8GB on each server so I need advice pour HV1 and HV2.

Thanks a lot for HV1 and advice about mapping. I will add the new RAM to the one existing so if I understand well, for HV1 I will have, after adding 4x8GB : A1-A2-A3-A4 and B1-B2-B3-B4. That's it ?

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6.2K Posts

August 5th, 2016 11:00

There will be 4x8GB on each server so I need advice pour HV1 and HV2.

HV2 population would be:

{1,2,3,4} {5,6} and new DIMMs in {9,10}

4 Posts

August 17th, 2016 01:00

Hello !

For HV1, it's ok and it works perfectly

For HV2, I moved 1-2-3-4-6-8 to 1-2-3-4-5-6 and added the new DIMMs at positions 9-10 : no boot, orange light.

I've tested the memory in HV1 : it works.

Do you have any advise ?

Thanks a lot

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6.2K Posts

August 17th, 2016 13:00

I've tested the memory in HV1 : it works.

What do you mean by this statement? What memory did you test and how did you test it? Are you referring to the HV1 configuration working in HV1 or the HV2 memory working in the HV1 server?

For HV2, I moved 1-2-3-4-6-8 to 1-2-3-4-5-6 and added the new DIMMs at positions 9-10 : no boot, orange light.

There is likely something about the memory that is causing an issue. Is all of the memory the same type(registered, unregistered, load reduced)?

Thanks

4 Posts

August 18th, 2016 03:00

"Valarion

I've tested the memory in HV1 : it works.

What do you mean by this statement? What memory did you test and how did you test it? Are you referring to the HV1 configuration working in HV1 or the HV2 memory working in the HV1 server?"

I mean that I have connected on HV1 the memory I wanted to use on HV2, which prevent HV2 to boot, and HV1 works perfectly with it so I know the memory is OK.

Memory type received : 8GB DDR3L - ECC - PC3L-12800 - CL11 ( 11-11-11 )

Seems exactly the same as the one we have already, except the capacity, the new one is 8GB, the old one is 4GB

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6.2K Posts

August 18th, 2016 10:00

I mean that I have connected on HV1 the memory I wanted to use on HV2, which prevent HV2 to boot, and HV1 works perfectly with it so I know the memory is OK.

Memory type received : 8GB DDR3L - ECC - PC3L-12800 - CL11 ( 11-11-11 )

Seems exactly the same as the one we have already, except the capacity, the new one is 8GB, the old one is 4GB

If the memory works fine with the exact same population in an identical system then it is likely an issue with a slot on HV2. I would check the hardware log for errors that may indicate which slot. If the system is not able to complete POST due to the issue then it may not log an error in the hardware log.

If the population works without slots 9,10 populated then it is likely an issue with one of those slots on the A or B lane, so it could be 4 possible slots. You will need to test by removing DIMMs one at a time from those slots.

Thanks

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