Thanx much to ALan and Oisin, for giving me light on
this topic. Still looking for the specifics on gtar
limitations (gtar --help doesn't say much...no reg.
man page), will try around gnu sites to see if I find
it. ALso trying to find out how to tell gtar to skip a
file when it encounters special characters on it
instead of exiting. For example, this file in a ~dir
caused gtar to exit, and did not backup any other user
files below it:
autosave/#\!usr0\!users\!xxxxxx\!.kde\!share\!icons\!sh
_Thanks
Oisin McGuinness said:
All tar's have some sort of limitations on file name
lengths.
Traditional tar's have 100 characters as the total
path name limit.
Gnutar can do a little better, when given the right
options, as can the
Compaq Unix/Digital Unix
tar if you use non-standard options. (man tar, look at
E option).
But this generic tar problem is why one should use
vdump (dump
on older systems) for real backups...
(See for example,
http://www.freebsd.org/doc/en_US.ISO_8859-1/books/handbook/backup-programs.html
for a discussion, with references to Zwicky's famous
study of torturing
back up systems. Using "Zwicky backup torture" at
google turns up
this link and many others...)
If you absolutely have to retrieve data from this
tape, a creative use
of
dd'ing off the raw tar file from the tape, and then
using perl or
something
else (dd might help), plus a detailed look at the
header structure used
by gtar (all a tar file really is a succession of
header data and file
data;
the header data is defined in the source code for
tar), you could
cut off the leading part of the file, and continue
untar'ing from the
rest of it...
Alan_at_nabeth said:
Any implementation of tar is going to have a limit on
the
size of the header written for each file.
This causes
a limit in the size of a file name that can be
stored
in the header. For gtar to write a tape that
is compatible
with "standard" versions of tar, the name is
limited to
about 100 characters. It probably has an
option (*) to
write an incompatible header, making the tape
on readable
by comparible versions of gtar.
If it doesn't, take it up with the author of
gtar...
(*) gtar is a GNU utility. GNU utilities
traditionally have
lots of options. GNU utilities are rumored to
contain LISP
interpreters. Kind of a "kitchen sink"
philosophy for
providing features...
ORIGINAL QUESTION:
Greetings,,
Doing on a diff for backup verification.
Backup done by collecting files using gfind:
gfind /fsystem -type f -xdev >> $bckupfile
then using gtar to back them up:
gtar -c --files-from $bckupfile -f $bkupdevice >
/dev/null
Problems:
1. File
usr2/users/roberts/TST_BLENDER/GOITST/360X180/src/temp_3049/goisst_360x180_1930_to_1994_or_climatology.f
gets truncated in tape (verified thru tar tvf) to:
usr2/users/roberts/TST_BLENDER/GOITST/360X180/src/temp_
3049/goisst_360x180_1930_to_1994_or_climatolo
[....note it did not finish the gy.f part..]
2. File
usr0/users/romano/autosave/#\!usr0\!users\!romano\!.kde\!share\!icons\!sheet#
Causes gtar to abort backup, not even skipping to next
file...
(i will have to redirect gtar output to a file to see
actual messages)
Question:
Is this is limitation issue...?
How can I overcome these two problems?
Apparently file [2]above is created automatically by
kde!
_Thanks in advance
_Richard
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Received on Fri Jun 08 2001 - 15:50:36 NZST