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Backup Exec 2012 - Overwrite Protection etc ???

Created: 04 Dec 2012 • Updated: 19 Dec 2012 | 7 comments
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Hi we have been using BE for many years and have just recently upgraded to 2012. This version is quite different, not least being the way it has setup different jobs for each server being backed up. We currently carryout Full backups of just two servers every night. We have a rotation of 4 'Day' tapes, 4 'Week' Tapes and 4 'Month' tapes. The backup jobs start at 21:00 and end at 05:00 the following morning. When I first upgraded, the jobs were running successfully, but I now haven't had a good backup since last Thursday. The job begins but during the evening stops and asks for the media to be removed and overwritable media added.From the 'Home' and 'Storage' screens it looks like backup jobs have been appending to the tape until now, when they have reached full capacity.Please read the following requirements and current settings:

I don't mind and quite like the thought that we get better data retention by appending backup data to tapes, however once it is full, we would like it to overwrite the oldest data.


1) Storage properties for the 'Daily Backup ' media set

  • Overwrite Protection Period : 7 days
  • Append Period - Infinite Append

2) Backup Options - Storage for each job

  • Append to Media, overwrite if no appendable media is available

When I put the tape in for each nights backup, I run an 'Inventory' job to ensure the correct tape has been recognised and that it is overwriteable. 

I am going to try reducing the Overwrite Protection from 7 days down to 5 days to see whether this helps, but could it be something to do with the fact there are now two backup jobs (one for each server) ? Why doesn't the backup start overwriting old data once the tape is full?

Any help you can provide would be appreciated.


Steve C

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Kiran Bandi's picture

however once it is full, we would like it to overwrite the oldest data.

Some portion of tape can't be overwritten. 

Every time data gets appended to a media, it's Overwrite Protection Period resets to defined. Which means, the tape which became full can be overwritten only after 7 days according to the current configuration and can be overwritten after 5 days if you make the changes you are proposing.

I would recommend you to fix a valid Append Period instead of using Infinite.


pkh's picture

When you append to a tape and it gets full, BE will always require an overwritable tape.  It cannot overwrite the front portion of the tape.

The OPP of a tape starts from the END of the last job that writes to the tape.  If you have a tape which your jobs are appending from Mon-Fri, the OPP will start from the end of the Friday job.

You should read this document to gain a better understanding of how OPP and AP works.

OPP and AP explanation

Steve Church's picture

Hi Guys

Many thanks for your replies. I changed the OPP setting from 7 days to 5 days (could probably set this to 6 days but as our backup window spans from 1day to the next, didn't want to risk being too tight) also changed the AP from Infinite to 2 days. I am now glad to say we had successful backups last night. I'll let the next few days backups run and if OK change the OPP and AP settings for our Weekly and Monthly sets.

To be clear though, we don't append Mon-Fri backups to one tape. We have the following rotation:

We have DAY A, B, C, D and E tapes to be used Mon - Thurs in rotation.

We use WEK A, B, C, D tapes on every Friday in rotation.

We then use MTH A, B, C, D tapes on the last Friday of every month in rotation.

Therefore we have 13 tapes in our backup set. We only ever do FULL backups (no incremental / diff).

Hope this makes sense !!! and as I say, last nights backups were fine so I'll see how it goes.

I'd be interested on what you may think regarding my now current OPP and AP settings.


Steve C

pkh's picture

If you are not going to append to your tapes, then 

1) Change the AP of all the media sets to 1 hour.

2) Change your jobs to overwrite.

For the Daily jobs, the OPP should be 6 days.

For the weekly jobs, the OPP should be 3 weeks since you have only 4 tapes.

For the monthly jobs, the OPP should be 3 months.

Steve Church's picture

Thanks once again.

Could someone just explain what happens regarding AP when there are multiple jobs.

Eg. I have two backup jobs scheduled to start at 21:00. The first server takes 4hrs to complete then the second job starts and takes further 4hrs.

When does the AP start? Is it from Start, End of first job or last job?

If it's start of first job, would I not need to set AP to at least length of first job?

Sorry for daft questions !!!

pkh's picture

AP starts from the time the first job overwrites the media, i.e. the start of the job.

If it's start of first job, would I not need to set AP to at least length of first job?

... because the first job is already overwriting the tape.  It is not appending to it.  Appending is for subsequent jobs.  The reason why I suggested that you set the AP to 1 hour is that by the time the first job finishes, assuming it takes more than 1 hour, the tape would not be appendable which is what you want.  I found that setting AP to 0 hour gives funny results, so 1 hour is the minimum.  I would suggest that you read the document quoted earlier so that you can understand OPP and AP better.

Kiran Bandi's picture

Append period measured from the time the media first allocated.

In your case/example if you are using same media set and want to use same media for backingup both the servers, then Yes you need to set the difference between start times of both the jobs as Append period. 

If you choose 1hr AP and 6 days OPP, your second job will not be able to use the media that was used by first job.

If i were i would have choosed 23 Hrs AP for daily jobs.