On Tue, Mar 02, 2010 at 02:40:14PM +1100, Cameron Simpson wrote: > On 01Mar2010 21:30, Mike McCarty <Mike.McCarty@xxxxxxxxxxxxx> wrote: > | Yes, it is. I suspect he meant a files based backup. With > | dump, what one gets is a dump of the file system itself, > | as opposed to the data it contains. With a files based > | backup, one gets a copy of the data saved, but not the > | file system. So, for example, using tar, or cpio, one can > | back up a system using ext3, and recover to a system which > | uses reiserfs. One cannot do that with dump and restore, > | which store the file system itself. The dump and restore > | work at a lower level than files based backup. > > I was pretty sure restore pulls "files" from the dump and writes to an > arbitrary filesystem (eg xfs or reiser etc). Dump accesses the filesystem > directly, but restore doesn't have that issue. Yes, you are correct. Furthermore, although dump accesses the raw device directly (and thus needs to know the specifics of ext*), the output of dump is *not* tied to the file system format; it is instead a (fairly) neutral format that consists of a series of records containing first, all directory information, followed by the data and metadata for each file being backed up (ordered by inode number). So, a file which is fragmented and spread out across a disk will appear in the dump output as a single blob. Having all the directory info at the start of the dump means that it's possible to quickly scan a backup to see if it contains the file(s) you're looking for. restore even has an interactive mode for that purpose. -- But Pity stayed his hand. "It's a pity I've run out of bullets", he thought. -- "Bored of the Rings" -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
