media set - overwrite protection period vs append period

[yong_look]

hi all

 in many occasions, i have seen this issue surface but i wonder if this is related to the below setting (see attachment)

 A number of the backup could not kick start because apparently the media is running out of space, upon checking, i found that the media is still holding a number of backup images that suppose to expire (the media set overwrite protection period was set to 45 days) and i suspect it might be due to the setting for the append period (was set to none - infinate allowed append)

i always thought the media set periods- overwrite protection period outweighted the append period, but in those circumstances, i am seeing the otherwise result, is that true?

 or perhaps, it was due to some other setting i have overlooked

yl

i am using BE12.5 with Windows 2008 OS

[pkh · Accepted solution]

The append period starts from the moment the media is first overwritten and will not change.  The overwrite protection period (OPP) will start from the end of the last job that writes to the tape.  See this document for a more detailed explanation of OPP and AP.

http://www.symantec.com/business/support/index?page=content&id=TECH5459

Assuming that you are using a tape and the OPP is 2 days, when you overwrite the tape on Monday, the tape is protected until Wed.  If you append to the tape, the entire tape, including the Monday backup set, will be protected until Thursday and so on.

[Colin_Weaver]

As well as the pkh info you also cannot 'expire' one backup set on a tape. Tape does not work like disk where we can erase/delet one backup set. An overwrite of a tape is in effect erase all backup sets from the tape.

An append is add data to the unused space at the end of a tape.