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Chad Huneycutt
Asked: 2009-07-28 09:13:50 +0800 CST

RHEL5 Xen dom0 max memory?

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I have a server with 48GB or RAM on which I have installed RHEL5 with the xen kernel. I think maybe this is normal behavior, but the kernel only seems to be able to see 32GB. I looked around online, and I found very little. I think a significant data point is that xm info reports total_memory as 49142 (MB, I assume), which I suppose means that I can utilize the 48GB for my VMs?

virtualization xen linux memory

1 Answers

  1. Best Answer

    If xm info reports all of the RAM then you should be able to assign it out to your domU's without a problem. I typically set the dom0_mem setting on the grub.conf boot line to limit the RAM the dom0 can utilize and save the rest for the domU's. I couple this with setting dom0-min-mem to 0 in xend-config.sxp to keep it from ballooning larger.

    I'm not aware if there is a 32GB limit to the dom0, but I've not had a system with that much RAM to be able to test it either. Xen requires a PAE-based kernel build so it should be able to address the RAM.

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