[net.unix-wizards] dumping active file systems

phil@sequent.UUCP (11/02/83)

4.2 BSD dump/restore (yes "restore") do not quite totally operate through
the filesystem.  Dumping is still done though the device (usually raw for
speed) but restores are done *only* on mounted filesytems and relative to
the current directory.  The biggest change is the added "i" flag to restore
that is interactive!  It puts you into a pseudo editor interface that lets
you skip around selecting files to restore.  It has to be seen to be believed.

The 4.2 filesytem make a tremendous difference in dump/restore times since
the tape runs at nearly tape speeds.  The only unfortunate side effect of
doing a restore through the filesytem is that the "ctime" of an inode cannot
be set to the ctime of the tape file (as old restor did).  One can certainly
argue which is correct.

-- 
	Phil Hochstetler (503) 627-9811
	Sequent Computer Systems
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msc@qubix.UUCP (Mark Callow) (11/07/83)

The new 4.2 dump/restore programs do all their stuff through the
normal block device interface and no longer do the inode mapping.
The "changes in 4.2" document (I think.  I don't have it handy
at home to check it is THE one) in discussing this says that it
makes the dump tolerant of changes in the file system during
the dump and implies that dumping of active file systems is
safe.
-- 
	Mark Callow, Saratoga, CA.
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