The virsh command provides a migrate parameter that we can use to migrate KVM instances between hosts. In the previous two recipes, we saw how to migrate instances manually with downtime. In this recipe, we are going to perform a live migration on an instance that uses either the iSCSI storage pool or the GlusterFS shared volumes that we used earlier in this chapter.
If you recall, live migration only works when the guest filesystem resides on some sort of shared media, such as NFS, iSCSI, GlusterFS, or if we first copy the image file to all nodes and use the --copy-storage-all option with virsh migrate, as we'll see later in this chapter.
