Hello All,
I'm very curious (and a bit concerned) about constant, once-per-second
disk accesses when running KVM virtual OS's on three SL-6.3 VM host
machines.
Whenever I start one or more VM OS's, I see disk write activity every
second, starting the instant I launch the VM. With quiescent VMs, each
instance of libvirtd averages about 15.5 K/s writes, and no reads. This
is with BSD- and Linux-based virtual machine instances.
All virtual machines have more than enough RAM assigned so there should
be no swapping activity. 'top' on any VM shows zero swap in use, but
'iotop' on the host servers shows constant disk writes for each instance
of libvirtd. This happens even when a virtual machine should be doing
no disk accesses at all. The date stamp on each .qcow2 or .img file is
constantly being updated, so that's where the I/O is going.
Is this normal? My main concern is wear and tear on the disks.
Any advice on how to reduce this activity?
Chuck
