FWIW - if you are looking at a backup approach with the dumpall, I have found that using a rsync to just mirror the file system is waaaaaaaay faster, and hence less prone to interuption. This is how it is recommended with a warm standby development, and works great, and also is far less consumptive of system resources. The big limitation is that if you are duplicating for an upgrade, it might be problematic since the file system dupes are PG Version specific I think.
regards, r.b.
