Dear all, I also found out that when the RBD snapshot is being run, the CPU utilisation on the KVM host will be shooting up very high, which might explain why the host becomes disconnected.
top - 22:49:32 up 3 days, 19:31, 1 user, load average: 7.85, 4.97, 3.47 Tasks: 297 total, 3 running, 294 sleeping, 0 stopped, 0 zombie Cpu(s): 4.5%us, 1.2%sy, 0.0%ni, 94.1%id, 0.1%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 264125244k total, 77203460k used, 186921784k free, 154888k buffers Swap: 545788k total, 0k used, 545788k free, 60677092k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 18161 root 20 0 3871m 31m 8444 S 101 0.0 301:58.09 kvm 2790 root 20 0 43.5g 1.6g 19m S 97 0.7 45:52.42 jsvc 24544 root 20 0 4583m 31m 8364 S 97 0.0 425:29.48 kvm 6537 root 20 0 0 0 0 R 71 0.0 0:17.49 kworker/3:2 22546 root 20 0 6143m 2.0g 8452 S 26 0.8 55:14.07 kvm 4219 root 20 0 7671m 4.0g 8524 S 6 1.6 106:12.26 kvm 5989 root 20 0 43.2g 1.6g 232 D 6 0.6 0:08.13 jsvc 5993 root 20 0 43.3g 1.6g 224 D 6 0.6 0:08.36 jsvc Is it normal when snapshot is being run on the VM running on that host, the host's CPU utilisation will be higher than usual? How can I limit the CPU resources used by the snapshot? Looking forward to your reply, thank you. Cheers. On Mon, Oct 7, 2013 at 7:18 PM, Indra Pramana <in...@sg.or.id> wrote: > Dear all, > > I did some tests on snapshots since it's now supported for my Ceph RBD > primary storage in CloudStack 4.2. When I ran the snapshot for a particular > VM instance earlier, I noticed that this has caused the host (where the VM > is on) becomes disconnected. > > Here's the excerpt from the agent.log: > > http://pastebin.com/dxVV7stu > > The management-server.log doesn't much showing anything other than > detecting that the host was down and HA is being activated: > > http://pastebin.com/UeLiSm9K > > Anyone can advise what is causing the problem? So far there is only one > user doing the snapshotting and it has caused issues to the host, I can't > imagine what if multiple users try to do snapshotting at the same time? > > I read about snapshot job throttling which is described on the manual: > > > http://cloudstack.apache.org/docs/en-US/Apache_CloudStack/4.2.0/html/Admin_Guide/working-with-snapshots.html > > But I am not too sure whether this will help to resolve the problem since > there is only one user trying to perform snapshot and we already encounter > the problem already. > > Anyone can advise how I can troubleshoot further and find a solution to > the problem? > > Looking forward to your reply, thank you. > > Cheers. >
