tar backup question
 

I am rendering image files in batches of about 30000 files. I need to make a tar backup to DLT tape. The rendering is faster than the DLT writing.

Could I start the tar backup of the directory while the files are still rendering?

Will tar recognize those files that did not yet exist while tar was started. This is a multi-volume tape backup taking many hours to complete.

Thanks.

No, it won't. An easy way to find this out is to do something like this.

cd /tmp
mkdir test
cd test
for i in 1 2 3 4 5 6 7 8 9 10;do touch $i;sleep 2;done

Then in another window, wait a few seconds, then do:

cd /tmp
tar cf test.tar test

Then a tar tvf test.tar will show you what it has.

Can you do the rendering in a such a way that the program rendering the images is working on the next directory while the tape script is tarring the directory that the renderer just finished?

I'm not sure how well this would work for you but I do something similar with my data backups. I have three computers with disks that get backed up to one computer, which then dumps the data to tape. The scheduling is such that the tape script starts after the first computer has dumped its data to the first directory. While that directory is being dumped to tape, the second computer starts dumping its data to the backup computer. By the time the backup computer is done writing the first computer's data to tape, the second computer is done transferring, and so on.

I hope this helps