Tuesday, August 8, 2017

memory - ECC RAM, Background Scrubbing, and IOMMU BIOS Settings



I'm upping the RAM in one of our servers from 2GB to 4GB. Looking around in the BIOS, I see the following settings:



DRAM ECC Enable (Enabled)

MCA DRAM ECC Logging (Disabled)
ECC Chip Kill (Disable)
DRAM Scrub Redirect (Disable)
DRAM BG Scrub (Disabled)
L2 Cache BG Scrub (Disabled)
Data Cache BG Scrub (Disabled)
IOMMU Mode (Disabled)


Should these be turned on? And for the background scrubbing options, various times are in nano and microseconds; how would one go about calculating the optimal time to use?




Additionally, IOMMU has an options for Best Fit and Absolute, and then allows me to set the aperture size in MB. What should this be set to? We're running VMWare Server on this box, so my basic understanding is that IOMMU is helpful, but don't know what the ideal aperture would be.


Answer



Sounds like the server your using is AMD based; here is some information on i/o virtualization and AMD's IOMMU option that might help. -> http://developer.amd.com/documentation/articles/pages/892006101.aspx -> Specifically under "What's an IOMMU."



Some more info related to chipkill and scrub modes in bios related to ECC with detailed information on ECC Scrubbing and performance when using some of these options -> http://episteme.arstechnica.com/eve/forums/a/tpc/f/77909774/m/346009152831


No comments:

Post a Comment

linux - How to SSH to ec2 instance in VPC private subnet via NAT server

I have created a VPC in aws with a public subnet and a private subnet. The private subnet does not have direct access to external network. S...