dump -L

[Victor Sudakov]

cpghost wrote:
> > > > > I always use "dump -L" to dump a live filesystem.
> > > > > However, when I restore the dump, I sometimes get messages like
> > > > > "foo.txt (inode 12345) not found on tape" or
> > > > > "expected next file 12345, got 23456"
> > > > >
> > > > > I thought this should _never_ happen when dumping a snapshot.
> > > > >
> > > > > What is it?
> > > >
> > > > Does nobody know the answer, or am I the only one experiencing the
> > > > problem?
> > > 
> > > I don't know the answer, but I get essentially the
> > > same behaviour.  I have never seen any data loss,
> > 
> > I gave an example below. The file "wins.dat" was not dumped. It is
> > indeed missing from the tape.
> > 
> > If this is not a data loss, what is it then?
> > 
> > [root at big ~] restore -b64 -rN
> > ./spool/samba.lock/wins.dat: (inode 2829098) not found on tape
> > expected next file 267, got 4
> > expected next file 2828988, got 2828987
> 
> Uh-oh :-(. I have no idea how the code works, but just a wild guess:
> what happens when a file is being created and a snapshot taken at the
> same time? 

I would very much like to know that. Creating a snapshot can take
several minutes on a large modern HDD. Many files can be changed
during those minutes.

> Isn't there a tiny window between inode creation and
> directory update? Or is file creation an atomic operation w.r.t.
> snapshots and dump?

-- 
Victor Sudakov,  VAS4-RIPE, VAS47-RIPN
sip:sudakov at sibptus.tomsk.ru