memory use

[lastgreatone]

I'm trying to figure out if a ProLiant 380 with 3GB RAM is actually only using 2GB. Online Spare Memory apparently uses the last DIMM slots for spare memory, not sure why. Can I change that configuration, so the server uses all 3GB on demand?

[Doug de Werd]

yes, that is the way that Online Spare Memory is configured. It reserves one third of the memory as a spare bank to kick in if one of the other banks fails. You can reconfigure this to standard memory using the ROM-Based Setup Utility (press F9 during startup).

Here is a link to the RBSU User Guide (see p. 18).
http://wwss1pro.compaq.com/support/reference_library/viewdocument.asp?source=347563-001.xml&dt=264


Look in the "Systems Options" area under "Advanced Memory Protection"

Thanks,
Doug

[lastgreatone]

Great, it set to Advanced ECC Memory (maximum memory)to the os. I rebooted, would you happen to know what is uncachable memory on the server? RHES 2.1 is running on this server and I see this in
/proc/mtrr
reg00: base=0x80000000 (2048MB), size=1024MB: write-back, count=1
reg01: base=0x00000000 ( 0MB), size=2048MB: write-back, count=1
reg02: base=0x400040000 (16384MB), size= 64KB: uncachable, count=1
reg03: base=0x400060000 (16384MB), size= 64KB: uncachable, count=1
reg04: base=0x400080000 (16384MB), size= 64KB: uncachable, count=1
reg05: base=0x4000a0000 (16384MB), size= 64KB: uncachable, count=1
reg06: base=0x4000c0000 (16384MB), size= 64KB: uncachable, count=1
reg07: base=0x4000e0000 (16384MB), size= 64KB: uncachable, count=1

[Doug de Werd · Accepted solution]

I don't know for sure, but it might be that it is reserving several 64 KB chuncks of memory for use as video RAM, hence it not being cachable..... just a guess, I wouldn't worry about it

You might find this interesting:
http://www.iglu.org.il/lxr/source/Documentation/mtrr.txt

Thanks,
Doug

[lastgreatone]

Thanks, that was quite helpful. I'm still puzzled as to why I see in dmesg (print of kernel ring buffer):
mtrr: no more MTRRs available
mtrr: no more MTRRs available
mtrr: no more MTRRs available

but as you say, I just won't worry about it.
Cheers,