ESX 3.5 MTRR Warning

[vjasonsum]

I see this message in the vmkwarning file at startup on a BL465c blade. Does anyone know if this should be changed and where the setting might be?

vmkernel: TSC: 85689 cpu0:0)WARNING: Cpu: 1006: cpu supports 40 bit physical address, but system is configured to limit the MTRR mask to 36 bits

Thanks in advance

[vmPUNK]

same thing here, just trying to figure out what it means

vmkernel: TSC: 65947 cpu0:0)WARNING: Cpu: 1003: cpu supports 38 bit physical address, but system is

configured to limit the MTRR mask to 36 bits

[kjb007]

This is typically seen on systems that allow alrger amounts of RAM. It is used to describe your memory, and which registers manage which range of memory (Memory Type Range Register).

This corresponds to a value in the ESX server configuration, which by default forces a 36-bit mask, even if your CPU supports larger. You can modify this value by going into the esx configuration tab, advanced settings, uncheck 'vmkernel.boot.force36BitMTRRMask'.

-KjB

[Col_Flashman]

I got exactly the same error on some new M600 blades I am setting up. I followed the advice here and unchecked the 'vmkernel.boot.force36BitMTRRMask'. It worked.

However, I'm not entirely sure what I have done in terms of host stability. Is it OK to set this just to clear this error in the vmkwarning log?

[kjb007]

You are allowing all of the available bits of our processor to be seen by vmkernel. You are removing the mask that only allowed the first 36 bits to be seen. Without this, you also would not see over 64 GB of ram. So, it is not solely for the purpose of clearing warnings in the log.

-KjB

[Col_Flashman]

I believe KJB007 has answer this question and should therefore get the cudos.