Media Set OPP and Backup Job Overwrite

[JohnyD]

I'm curious as to the difference between the OPP you set for your media set and the overwrite setting for your actual job, Overwrite Media / Append to media, overwrite if no appendable media is available / Append to media, terminate job if no appendable media is available.

I have a job running full's twice a month with diffs running in between. I suspect I would want my diff's to overwrite each night as a differential's last backup is the only one you need.

[Colin_Weaver · Accepted solution]

The overwrite setting in your job controls whether or not the job will start with an Append or an Overwrite - this then detemines what type of tape it is looking for at the start of the job (i.e. does the job need to find an overwritable tape or an appendable tape.)  This only affects the start of the job as if the job goes to a second tape then it will always do an overwrite so look for an overwritable second tape.

The Media Set is a logical container that defines how long a tape should be protected from being overwritten and how long the tape should be appendable for.  The job will need this to be defined as well for the media handling to work.

As such they are totally different settings that combine (with some other settings) in order for Backup Exec to decide which tape to use.

[RahulG]

You define the Overwrite protection period and the append period on a media set which nothing but a logical container which protects you tape . By default all the new tapes are in Sctrach media set . When you run the 1st backup job the tape is picked up from the the scratch media set and is associated to the media set define in the backup job properties .
Later when you run the overwrite job ,depending on the settings you have under tools--Option media mangement -- it would either select the recyclable tape (whoes opp is expired) or a scratch media .
You can specify if it should overwrtie scratch media 1st or recyclable media .
Refer the following document
http://support.veritas.com/docs/192265
 

Advanced Device and Media Management (ADAMM) Information which includes An explanation of the "Overwrite Protection Period" and the "Append Period"