I am looking for input regarding how to backup DomU machine filesystems. My system is a Debian Lenny Dom0. All DomUs to date are Debian Lenny as well. All DomUs are backed by LVM. Initially, because of the use of LVM, I had planned to conduct backups from the Dom0 to an externally attached eSATA drive using LVM snapshots. However, recent discussion on the Xen mailing lists have caused me to question this approach. The discussion focussed mainly on the inability of snapshots to backup data that is in cache at the time the snapshot is created. This has led me to consider making an NFS server DomU. I would plan on backing the "disks" in the DomU with either LVM partitions or by passing the physical disk of the eSATA external drive. Then I would modify the DomU Xen config files to mount the NFS shares to accomplish the backup. The backups would be done at the DomU level in this configuration over the virtualized network to the NFS server. I would like to get some input on which approach may be better. Not of my systems are highly mission critical. They are however, highly utilized and would cause a great deal of stress on my behalf if they weren't easily brought back online. Are there backup configurations that I haven't considered to date that may be better than the two approaches above?