Video Screencast Help

Cartridge Overwrite protection confusing

Created: 20 Aug 2014 • Updated: 20 Aug 2014 | 2 comments
This issue has been solved. See solution.

Hello All;

Need to clarfy something in my mind about BE overwritte protection issue...

I've a BE2014 and a connected LTO tape. The cartridge capacity is 400GB. I need to backup 200GB data daily and want to use cartridge capacity with maximum efficieny. This is my scnerio;

  • 1'st Saturday : I use a blank media and backup 200GB to the media (remained 200GB)
  • 2'nd Saturday: I run another backup job and append 200GB additional data to the media (no more empty space)
  • 3'rd Saturday: I run another backup job 200GB. Overwrite protection is 0. Also it's set as "Append to media, overwrite if no appendable media".

Could you please tell me which data will be overwritten; 1'st Saturday or 2'nd Saturday? Of course we normally want to overwritte the 1'st Saturday data. What is the behaviour of BE and how can I control its behaviour?

 

Regards

Tirelibirefe

Operating Systems:

Comments 2 CommentsJump to latest comment

Larry Fine's picture

Could you please tell me which data will be overwritten; 1'st Saturday or 2'nd Saturday?

Essentially both backups will be lost.  The tape itself will be overwritten, which will obviously overwrite the 1st Saturday.  But the 2nd Saturday set is no longer available.

Think about what would happen if the 3rd Saturday backup had grown to 205GB.  It obviously could not simply replace the first Saturday backup, hence the need to re-use the entire tape.  Tape is a sequential system, not a direct access system.

If you find this is a solution for the thread, please mark it as such.

SOLUTION
pkh's picture

When you use "Append to media, overwrite if no appendable media" and OPP = 0, you might find that your tape is overwritten on the 2nd week. Depending on circumstances, your job might not append to your tape. See my article below

https://www-secure.symantec.com/connect/articles/w...