I would like to hear what solutions people have implemented for backing up their Filers.

A very good question.

We recently bought a small filer, an F230 max'ed out on drives, with plans over the next two years to fill it to capacity.

We migrated file service to it from a DEC Alpha running Digital Unix. This mechanism worked well, but was starting to feel slow, and we wanted to add cleaner file service to our growing NT user base. Samba looked useful, but a bit scary in terms of support.

We've been running DEC's version of Networker on the Alpha, and considered NFS-mounting the filer's disk space, which would allow us to continue on in that path.

But loading the network at night was somewhat unattractive, though not much of a problem in our shop. Attaching our EXB-210 8mm jukebox with two drives directly to the filer looked more interesting, and BudTool seemed to be the best choice at the time, because of its ability to speak NDMP to our tape jukebox. Also, we have had problems with Networker's media and file databases, and BudTool promises to eliminate this problem.

After getting BudTool in house, we discovered that configuring this package to suit our wishes was not going to be easy: configuration files are located together in one subdirectory, but they must be edited by hand (whereas Networker provided full gui's for everything), and many are called ".whatever", which of course is designed to hide these configuration files from casual "ls"'ing. Hiding configuration files in a permission-protected directory makes little sense to me, and was somewhat of a pain.

Further, it took us a while to figure out how to configure the software to speak to the jukebox, and once that was done, we found that the few full backups we attempted would hang somewhere along the way for hours, after which they would wake up and keep going. Our network configuration is relatively simple-minded and I would describe it as very robust; none of the other ~50 devices on our network seemed to experience any problems at the same time that Networker was upset about something.

The backups that did run smoothly failed to fill our tapes: our drives are (I think) 8505XL's, which do take the 7Gb/14Gb-compressed 160m 8mm tapes, yet Networker called them "full" after putting at most 4.5Gbytes on them. By this time our interest in BudTool was waning. When we tried file restores, we found that the recovery tool could list all of the instances of a given file to choose from, but the recovery window could not tell you which of three or four tapes in a full backup a given file was stored.

When we timed backing up via BudTool versus Networker's NFS backups, we found that NFS was slightly faster in our level-0 tests than BudTool which was driving the filer-attached jukebox via NDMP.

We were also told that many of the configuration problems we were experiencing resulted from the fact that we did not have a barcode reader in our jukebox. We investigated getting a barcode reader, but found that we would have to abandon our tape-naming schemes to support one of the many different label standards. While we've always known a barcode reader would speed up tape identification even in use with Networker, it had never been a big issue with us in the past.

The folks at BudTool report that the tapes-not-filling problem could probably be fixed by adjusting some blocking-factor parameters buried in some of the config files. Perhaps this would also have improved speed of the backups. Also, there are rumors that if backups speak NDMP-1 instead of NDMP-2, they are less-likely to hang. In either case, these solutions seemed indicative of future problems: we never worried about blocking factor issues with Networker, and issues about reliability across protocol versions is definitely an unwelcome topic with respect something like backups which require resillience and sturdiness.

Our problems with Networker surround the fact that neither DEC nor Legato presented us with a "care and feeding" document for their software. After doing a fair amount of digging, we have developed procedures that are run by cron to keep the databases in order and in good shape, so we have decided for now to stick with Networker. While we continue to use the automounter on our Unix systems, we added manual mounts to another directory on our Alpha through which the backups are made, and we added an entry to /sbin/{init.d,rc3.d} to issue these mounts at boot time, lest we back up empty mount points.

Next year we hope to switch to another media for backups, and plan to check out the Veritas product, which is said to speak NDMP by that time. We would also like to see how BudTool changes over time to become easier to configure and use. The Networker product as sold through DEC that we are running on Digital Unix 3.2c is not Legato's most recent release by any means, so we would be interested in seeing that next year as well, though we keep hearing fluctuating timetables regarding their ETA for NDMP.

Don Glascock