Hi, I have xen on a debian lenny with more then 20 VM. The supermicro
server has a raid10 with a good performance, but I have IO issues when
one VM is making backup, it affects the performance of the other VMs.
I've setup cpus, vcpus, sched-credit between dom0 and domUs as doc
recommended, but I'm still facing IO problems. So I found a way to
mediate disk access with ionice from the dom0. I mean changing
priority to domUs PID. See below more details.
I'm using CFQ scheduler
dom0:~# cat /sys/block/[sh]d[a-z]*/queue/scheduler
noop anticipatory deadline [cfq]
noop anticipatory deadline [cfq]
It's a part of ps regarding block devices:
15747 ? S< 0:00 \_ [blkback.64.xvda]
15748 ? S< 0:54 \_ [blkback.64.xvda]
20353 ? S< 0:00 \_ [blkback.71.xvda]
20354 ? S< 0:05 \_ [blkback.71.xvda]
2361 ? S< 0:00 \_ [blkback.112.xvd]
2362 ? S< 0:15 \_ [blkback.112.xvd]
26596 ? S< 0:00 \_ [blkback.122.xvd]
26597 ? S< 0:00 \_ [blkback.122.xvd]
27203 ? S< 0:00 \_ [blkback.123.xvd]
27204 ? S< 0:00 \_ [blkback.123.xvd]
Finally, I change these PIDs with ionice and make several tests but
I'm still confuse with the results. My question:
Does anybody on this list use ionice to mediate disk priority to disk
intense domU with ionice from dom0?
appreciate your help.