I use kvm as hypervisor and nfs(nfs server on centos 6.4) as primary and secondary storage.
I use server A as host node and B with 1 hdd as primary storage.When I create 20 vms,I find the disk io performance is very low. At first I think the bottleneck is from the hard disk,because there are 20 vms on a single hdd.So I attach another 4hdds on server B and increase the number of primary storage from 1 to 5.Now there are 20 vms allocated averagely on 5 primary storage(4 vms per storage),but the vm disk IO performance is the same as before. I think NFS may be the bottleneck,but I don't know if it is true.Does anyone have a good idea to help me finding the real reason?
