VM out of memory causing load on Ceph.

[watnow101]

Hi.

I am currently facing the following problem.

I have a couple of VM's with 1 Core CPU and 1GB RAM allocated to them. After a software upgrade on it the 1GB RAM is not sufficient maxing out the RAM. This causes high CPU usage from the kswap0 process.

The CPU utilization then spikes to between 200 and 300% when I look on the summary of the VM, which over utilize the allocated CPU. (I have fixed this by setting cpu limit to the same as the allocated cores and looks like it mitigates the problem.)

When the CPU spikes to 200 - 300%(see attached "VMCPULoad.png" because of no available RAM left, causes very high load on CEPH(see attached VMRead.png)

When this happens and the VM has this high read rate causes Ceph Read IOPS on the cluster to ramp up to between 3 000 and 20 000.

 

[shrdlicka]

Hi,

sounds to me like your VM is using the swap space because you ran out of memory. If your VM storage is backed by Ceph then you will see a high load on the Ceph storage.

From which version did you upgrade?
Did you check what is consuming memory in your VM?