Does 'tar' & 'cpio' support archiving of files larger than 2gb

[Jeffrey Davis_1]

Hello,
I'm looking for confirmation that 'tar' & 'cpio' can or cannot correctly handle the archiving of files larger than 2gb in an HP-UX 10.20 environment. The manuals say that they don't directly support it, but I did a test and it seemed to write out the proper block size. Should I trust this? And what is a good way to list the contents of my archive tape once it is created? I can't seem to get the "tar tv /dev/rmt/2m" command to work. I'm supposed to be able to use the latter command to list my archive file set I think.
Thanks in advance.

[James R. Ferguson · Accepted solution]

Jeffergy:

'tar', 'cpio' and 'pax' do NOT support archiving files larger than 2GB nor files that have user or group IDs that are greater than 60,000.

See the man pages for each.

...JRF...

[Darren Miller]

Jeffrey,

Regarding the first half of your question, tar and cpio don't support large files. See the large files white paper in the /usr/share/doc directory for a list of commands that do and don't support large files.

Regading your second question, your tar command was missing the -f option, which says that you want to specify the device file to read a table of contents from. Without the -f, tar just looks on /dev/rmt/0m. Try this:

tar -tvf /dev/rmt/2m

Good luck!

[Bill Hassell]

It's important to note that large files are fairly new in Unix land (remember that Unix is pushing 30) and the classic tools (tar, cpio, pax, dump) were written long before the concept of a gigabyte on one disk even existed. These tools cannot be enhanced because to do so would render the backup unusable on any other system.

If you are going to use large files, the fbackup is the choice (for a lot of additional reasons including reliability and speed). Or you can download the GNU backup utils like GNUtar which handles large files...but you'll need to port the program to every machine that needs to read the new format.

[Markus Banfi_1]

You can get GNUtar (precompiled and the source) at http://hpux.asknet.de/hppd/hpux/Gnu/tar-1.13.18/. I use it a lot (also with >2GB files) on HP-ux 11.00 and never had problems.