Re: Packet writing and backups (was: Re: program for backing up data)
On May 20 2003, Jens Axboe wrote:
> On Tue, May 20 2003, Rogério Brito wrote:
> > I am compiling my kernel (on i386) with packet writing support
> > right now and I'll keep the list posted on the results I get.
> > I'd appreciate if other people did the same.
>
> Sounds interesting, I'd love to hear how well pktcdvd works for
> something like that today.
Well, I tested it now on _i386_. I had moderate success. The
first thing I tried (just as a smoketest) was to compile a
copy of some of my texts with LaTeX work directly on a CD-RW
(which are the main reason for me looking for packet writing
as this is my M.Sc. work which is due next month!).
This worked fine and I generated a lot of data (the document
that I was compiling generates a 2MB Postscript file). Since
many files are created (for indexes, table of contents, table
of figures, table of algorithms etc), I figure it is working
well.
Well, in fact, I had a problem: symbolic links are not working
well, but I don't really know if this is a problem with UDF or
with packet writing.
See this:
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
dumont:/mnt/pktw# ls -l
total 0
drwxr-xr-x 2 root root 40 May 19 22:20 lost+found
drwxr-xr-x 2 rbrito root 140 May 20 00:46 rbrito
dumont:/mnt/pktw# mkdir tmp ; cd tmp ; ln -s ../rbrito ; ls -l; cd ..
total 0
lrwxrwxrwx 1 root root 18 May 21 09:43 rbrito -> ..#E045/rbrito
dumont:/mnt/pktw#
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
OTOH, some links (in a given directory) are working well:
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
dumont:/mnt/pktw# ln -s rbrito/ a_link ; ls -l
total 0
lrwxrwxrwx 1 root root 11 May 21 09:46 a_link -> rbrito
drwxr-xr-x 2 root root 40 May 19 22:20 lost+found
drwxr-xr-x 2 rbrito root 140 May 20 00:46 rbrito
dumont:/mnt/pktw#
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Is packet writing tied to UDF or can I really use any
filesystem that I like, to debug?
I'm attaching the output of dmesg | egrep -i "(pktcdvd|UDF)"
to this message.
Anyway, I was able to do what I wanted creating hard links and
it seemed to work well, without the problem with symlinks and
relative paths.
After that, I tried to create a tar file of my home directory.
Then, the fun part began. :-) There is some data corruption
somewhere... :-)
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
dumont:/mnt/pktw/rbrito# ls -lAF
total 118208
-rw-r--r-- 1 rbrito rbrito 121044007 May 20 00:51 rbrito.tar.gz
dumont:/mnt/pktw/rbrito# ls -lAF
dumont:/mnt/pktw/rbrito# file rbrito.tar.gz
rbrito.tar.gz: PDP-11 old overlay
dumont:/mnt/pktw/rbrito#
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
And I indeed checked the file and it's not really my data! :-)
I can put the first few blocks of the file on a homepage, if
wanted...
> I haven't tested on ppc hardware, I suppose I should know that I
> have a superdrive enabled beast...
I still haven't had the time to try it on ppc... :-(
[]s, Roger...
--
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Rogério Brito - rbrito@ime.usp.br - http://www.ime.usp.br/~rbrito
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