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 LTFS - Copy issue

christopher lowdenc's profile image
christopher lowdenc posted Sat May 17, 2025 04:16 AM

Hello

I am using 

sudo cp -av '/mnt/49c57912-2bd6-4f31-a2b7-6df585bc9f40/LOWDEN_PIX' '/mnt/ltfs/sg1/000041'

to copy from a HD to an LTFS tape.

The copy starts very well but after a few minutes, the copy grinds to a halt on an arbitrary file and the drive starts rewinding and forwarding up and down the tape until I crash the command. I get the same sort of issue when I use the finder or mucommander to do the same thing.  Is there any reason for this? How does LTFS manage the file copying? Thank you

Martin Haussmann's profile image
Martin Haussmann posted Mon May 19, 2025 02:06 AM

Dear Christopher

Your description sounds like a corrupted Cartridge, as the Drive starts winding for and back. There are some checks, i think You did

  • Does the job stop at the same file when you do a retry?
  • Same behaviour with another Cartridge? Same file where the job stopps?
  • Copy to another HDD is ok?

as of the command, i think, you are coping photos. I sometimes get a corrupted file on IT, when i do a massive copy from the camera even if the filename was copied correctly and the filesize seems to be ok, but the content of the picture was crashed.

Kind regards Martin

christopher lowdenc's profile image
christopher lowdenc posted Sun May 25, 2025 08:55 AM

After many tests, I have a workflow that works for me.

This issue was on all tapes and drives and from different sources. I suspect that the error came from a LTFS formatting rule rules="size=512K" I was using

sudo /opt/ibm/ltfssde/bin/mkltfs -f --device=0 -n000041 -s000041 --rules="size=512K" --device=/dev/sg1

I revised the formatting code to 

sudo /opt/ibm/ltfssde/bin/mkltfs -f --device=0 -n 000016 -s 000016 --device=/dev/sg1

And things started to be better.

But the real difference was using a copy app called "qcommander", a QUANTUM variant of "mucommander". 

https://github.com/mucommander/mucommander

Quantum advised to use this app instead of the finder when I had a QUANTUM LTFS server setup.

The advantage of this app is that I can see the copies moving forward, so I can see if and when the copy gets stuck.

It's a java app so it works on mac, windows and linux. 
For the moment, I have been able to copy 4TBs with any real issues.
Thank you for your interest.

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