dump | restore fails: unknown tape header type 1853384566

Daniel O'Connor doconnor at gsoft.com.au
Tue Mar 24 20:05:03 PDT 2009

On Wednesday 25 March 2009 12:38:04 Mikhail T. wrote:
> Daniel O'Connor написав(ла):
> >> morning is still hanging (in sbwait) -- I've never seen this before. I'm
> >> also very troubled, that such an important functionality (dump/restore!)
> >> is sooo problem-prone, and yet so few people seem to care...
> >
> > Well, "works for me".
> Well, would like a login on this system to take a look for yourself? I
> can reproduce the problem easily.

I don't know the internals of dump/restore :(

> >> Is the official view, that dump is obsolete (and already bit-rotten),
> >> perhaps, and use of tar is encouraged instead?
> >
> > I've never had dump fail but it IS rather crusty and slow.. That said tar
> > doesn't cover all the information I believe.
> So, if dump/restore ain't it, does FreeBSD have a supported way of
> making filesystem-level backups, that's both modern and covers all
> aspects (like flags)?

I would try a pax archive, eg..
tar --format pax --one-file-system -pcf - -C / . | tar -pxf - -C /mnt/newdisk

According to the libarchive-formats page this handles ACLs & flags, my testing 
shows it handles flags (at least). eg..

[midget 13:30] /tmp/test2 >touch foo
[midget 13:30] /tmp/test2 >chflags uchg foo  
[midget 13:30] /tmp/test2 >tar --format pax -zpcf /tmp/test.pax.gz foo
[midget 13:30] /tmp/test2 >rm -f foo
rm: foo: Operation not permitted
[midget 13:30] /tmp/test2 >chflags nouchg foo
[midget 13:30] /tmp/test2 >rm foo
[midget 13:30] /tmp/test2 >tar -pxf /tmp/test.pax.gz                  
[midget 13:30] /tmp/test2 >ls -lao
total 30                          
drwxr-xr-x   2 darius  wheel  -      512 Mar 25 13:30 .
drwxrwxrwt  53 root    wheel  -    28672 Mar 25 13:29 ..
-rw-r--r--   1 darius  wheel  uchg     0 Mar 25 13:30 foo
[midget 13:30] /tmp/test2 >rm -f foo
rm: foo: Operation not permitted

> That said, I point out, that for me, dump is not failing (although it
> did hang this morning). It is the restore, which fails to read dump's
> output:

You can't tell the difference between dump producing mangled output or restore 
bombing out on valid input..

Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C

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