Simple question re: TAR

[Chris Elmore]

Aloha Good Folks,

I am tarring a folder directly to my file system and at the end of the TAR processing, it says:

"Tar: end of tape
Tar: to continue, enter device/file name when ready or null string to quit."

I press enter and then:

"User entered a null name for next device file."

...and I am returned to my prompt. I just want to know if this is normal behaviour for TAR and if everything is ok. I have run TAR direct to tape before and I have never seen this message when TARing to tape. Any help is greatly appreciated.

Very Respectfully,
Chris Elmore

[Steven E. Protter · Accepted solution]

I get very nervous when a tar file exceeds the size of a tape. Call it what you will, but I'm not comfy recovering a tar file that is spread across two tapes.

They get seperarated, and when that happens it will be when you REALLY need the tape.

That being said, I do believe that the functionality you are seeing is built into tar and is not abnormal.

SEP

[Brian M Rawlings]

Chris: I haven't seen this, and I tar to files all the time. Some things to check, maybe...
1> Is your file system filling up to 100% used? This might show up as an end of , and request another (file system, in this case).
2> Are any of the files you are archiving (taring?) larger than 2GB? 'tar' can't handle such, with a variety of confusing results and messages.
3> Have you tried 'pax', instead? It is newer (no 2GB limit, for instance). If you have 'ignite' loaded, you should have 'pax' on your system, that's what 'make_tape_recovery' uses.

Good luck!! --bmr

[Patrick Wallek]

That is normal behavior. You are probably seeing it because you don't have largefiles enabled on that filesystem and you ran into the 2GB limit for a file. If you want to avoid this, just enable largefiles on this filesystem.

I have never had any problem with tar spanning tapes. It works very well.

[Florian Heigl (new acc)]

I haven't seen that message, and I don't think it's ok as it does not say that there was no more input, but the output medium was full.

a few things come to my mind:

- target filesystem full
- hit a limit set by ulimit -f (i.e. AIX sets defaults here)
- hit a filesystem limit (largefiles enabled?)
- 2GB limit issue of tar?

please check the size of Your output file, and for now consider the backup incomplete.

You might want to diff a tar -tvf outfile to the origin folder.

If You hit the 2GB limit in tar (usually not, this should only apply to *single* files, not to the target), then consider using gtar (eeeeeek) or star.

greetings,
florian

[Patrick Wallek]

Tar cannot archive files larger than 2 GB, or with a patch 8GB. That would *NOT* cause this error.

You can create a tar ball that is larger than 2GB. Tar has always done that. Otherwise you wouldn't be able to write to the multi-GB tapes (DDS2, DDS3, DLT, etc.).

The file you specify after the '-f' option to tar (tar -cvf filename.tar) essentially has no limits other than your filesystem size. tar doesn't care how big that gets.

A full file system might, but you would see other errors if that were the case.

[Chris Elmore]

Aloha Folks,

I do appreciate all of your quick responses to my post. I do not have large files set on my filesystem, and the TAR did stop at 2GB, so filesize limits seems to be the culprit. In light of this, I am opting to TAR this to tape instead. Thanks folks, I leave here today a happy customer.

Very Respectfully,
Chris Elmore