LinearTapeFileSystem / LinearTapeFileSystem/ltfs

Recover from tape without partition label?

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question
Dominant language
C
Stars
352
Forks
110
Avg merge
2h 50m
Merged PRs (30d)
2

Description

I have a system that works just fine with ltfs, so this it not at much about hardware or driver issues...
I have a tape that is now 2-3 years old which I think may hold a file that I would like to recover.
I think the tape may have been "overwritten" at some mount when there was an issue where you could mount and overwrite some of the tape if you did append, or close the tape correctly (sorry but can't remember the details).
I'm now just trying to see if I can do some magic and recover something from the tape anyway...
But I am unable to mount.. it keeps telling me there is no partition label...
I have also tried ltfsck with the full recovery and even deep recovery, but it doesn't even "get going" as it cannot get past the partition label issue...
I then tried to dump the tape to a file to maybe "work" with it a bit easier, but maybe it's my lag of knowledge, but a "simple" dd -if=/dev/sg29 -of=dump -bs=1024 doesn't seem to read anything off the tape...

Is there any way to read all the tape an try to see if there is a "lost" file table or even find some file headers? (not sure how the files are stored)... anyway it's only one tape (LTO8) so if someone can point be in a direction that may work, or forever kill my hope of getting the file back ;-)

I'm currently running ltfs version 2.5.0.0 but the tape would have been written with an older version.
I'm on a standard Ubuntu 24.04 and the hardware is just a standalone IBM HH LTO8 which is SAS connected.

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reviewing the reported ltfs 2.5.0.0 behavior around ltfsck recovery, partition-label handling, and reading from /dev/sg29; the issue does not name source files or tests. Reproduce the mount, full/deep recovery, and dump attempts on an LTO8 setup if available, then determine whether tape contents or file headers can be recovered and document the result.

Written by the indexing model from the issue text.

Assessment

Tech stack
c, linux, ubuntu
Domain
operating-systems
Issue type
Bug
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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