"No good" is a bit harsh.
Files that are open at the time the backup is made may be corrupted. The disk will look like it would if you yanked the plug on a running system. This means that an fsck will certainly be required. It means you *may* lose data. It means you really shouldn't rely on this as your DR strategy. However, it's lots better than nothing.
There are products which do a nice job of file-level backup of Linux/390 systems. Most of the commercial ones require a z/OS server, alas. However, Amanda doesn't, although L/390 tape support is pretty rudimentary.
UTS Global offer a suite of tape products which give linux more comprehensive tape support. It allows users to send tape mount requests to operators or a STK tape silo, mount requests are queued if no tape drives are available, they can be requeued by operators. It provides similar functionality to OS/390's tape drive management. Along with a set of user commands there is an api available too.
One of the features is distributed tapes. Where one linux/390 system can have tape drives attached but users from other *nix systems (linux/390, linux/x86, solaris) can mount tapes and then access them as if they were locally attached - there is no need to move tape drives from one system to another.
We also offer a backup and restore product called BAR which supports the tape suite.
Paul Winder
