----- "Ken Bass" kbass@kenbass.com wrote:
It sounds like the domU is impacting the overall Xen performance. Is there anything I can do to tune this? It kinda defeats the whole Xen virtualization concept if a single CPU messes up the network. I am going to try to add a 'nice' to the crontab for the 4am job, but still, something doesn't seem correct. Any suggestions would be much appreciated. Thanks!
In high I/O environments or ones with a lot of unpredictable guests, it's a good idea to pin dom0's CPU(s) to physical cores and exclude those cores from the guests. I find that dom0 usually only needs one CPU (pinned to one core) in almost every environment. For example, on an 8 core box, dom0 gets CPU 0 (dom0-cpus 1) and all of the guests use 1-7. The occasional firewall/load balancer/something else high-I/O guest would also gets its own core, also excluded from use by the other guests, but you should avoid that until you find that it's necessary.