>The actual reasons why one might prefer tar to dump are that tar is >cross-platform ... >... and tar allows you to make backups of arbitrary (sub-)directory >trees instead of entire filesystems.
In addition to that, the reason tar is **strongly** pushed on Linux is that dump works with the raw disks while tar goes through the file system to get its data. The more aggressive the OS is about caching file data (and metadata) in memory (which Linux tries very hard to do), the less likely it is the raw disk has the "real" data, or at least a consistent version of it. Linus sent out a pretty firm "you should never use dump" E-mail quite a while back. On the other hand ... I don't (didn't) use tar at Purdue, in general, because it changes the access time on the files it backs up. That's a very bad thing. If you're about to mention --atime-preserve, don't :-). Setting that flag causes the change time to be altered. Our workaround was to use a GNU tar wrapper (2000+ lines of finely crafted Perl) for LVM volumes that created a snapshot and backed that up. We just ignored the access time problem for file systems not under LVM control. >Toomas Aas John R. Jackson, Senior Systems Analyst, Engineering Solutions, Inc
