problems with Nice and Dump in FreeBSD 6.1-Current (Stable-#5)

[Alex Zbyslaw]

backyard1454-bsd at yahoo.com wrote:

>I forgot about nice being interal to csh, that is
>likely to source of my problems...
>
>I use this for a dump
>
>dump -0 -C 32 -f - |bzip2 --best | dd of=/foo/bar.dbz2
>
>and then on a restore
>
>bzip2 -dc | (cd /foo; restore -r -f -)
>
>
>the error I get is
>
>expected 234234 got 234237
>expected 234235 got 234238
>expected 234236 got 234239
>... ...
>
>expected 234250 got 234267
>
>which fills up the screen with seemingly corruption
>errors, then the restore bails with an error asking if
>I wish to continue, if I continue it fails. I will get
>a screen dump of the error when I can dig up the
>corrupt dump file, and or make a new one. I believe
>the error is something about inodes missing or being
>corrupted.
>
>this exact command syntax works on everything but my
>usr filesystem.
>  
>

The restore man page does tell you why this happens (I know because I 
was just reading it today :-))

You are doing this dump on a Live Filesystem.  To do that use the -L 
option to dump (FreeBSD 5.X or later) which will snapshot the filesystem 
first.  Either that, or do what we had to do for years and drop down to 
single-user mode and make sure no processes are running to change the 
filesystem.  Dump needs the filesystem to be static.

Then when you restore you will get precisely *one* similar "error" (at 
least on 5.4), which I can't explain but can say *does not matter*.  I 
have restored several such dumps and compared them to the original 
filesystem and they are fine.  You should do that yourself for your own 
peace of mind.  (I do similar to you but with gzip and on 5.4).

The "error" you'll get should be:

     expected next file <inumber>, got <inumber>
             A file that was not listed in the directory showed up.  
This can
             occur when using a dump created on an active file system.

and I think it must be some artefact of the snapshot/dump interaction.

If you use -L and *still* have trouble then it sounds like a bug.

--Alex