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