Hi,
I am having a problem with the behavior of --listed-incremental when the
tape of a single-volume archive fills up.
To avoid the backups on subsequent days becoming increasingly larger, I
want the incremental index to list the files that were actually backed
up before the tape was full. However currently, I seem to get an index
saying that nothing was backed up on the full tape (its uncompressed
LTO-4 = 800Gio per tape).
I am wondering if there is a way to make this happen without too much
difficulty.
One thing I have not tried (because it would create a multi-volume
archive with the second and later volumes missing) would be to specify
"--tape-length 800000000000 --info-script=/bin/false" however given the
observed handling of tape full I would suspect that doing this would
have the same result as a simple broken output pipe[2].
Hope someone can help with this.
J Bohm, Software Developer.
Additional notes:
1. This is on a Debian 5.0.x(Lenny) system with its corresponding
version of GNU tar 1.20, but compiling another tar version to make
things work would not be much of a problem.
2. I am piping the output from tar through a double-buffering program
similar to the classic "buffer" program in order to reduce shoe-shining
in the tape drive caused by the disk being slower than the tape. The
buffer is configured to buffer up about 792 MibiOctets of archive at a
time, write lots of 100Kio tape blocks continuously in a burst at tape
speed, then sleep until the buffer is full again. Thus tape full
technically manifests itself as a broken output pipe rather than a real
disk full error code in case that makes any difference to tar.
3. This is a production system, I really need the backup to work 5 days
a week, 52 weeks/year. As each backup run may take up to 18 hours (2
hours lead time + 1 minute/burst), I cannot do much full scale
experimenting.
4. This is all done by a cron job, no human interaction possible.
