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Backup using more tapes than it should

Level 2


I currently run a weekly backup of our servers that is ~3TB is size, onto LT04 tapes. Even if there is zero compression, that should only take around 4 tapes. Currently it takes  usually 6, but sometimes 7. Just wondering if anyone has run into a similar problem or knows where I may have a setting wrong to cause it to span so many tapes.

Basic rundown of backup:

Using Backup Exec 2014

Run 4 seperate backup jobs

Backing up 3 servers with a normal backup agent + 1 SQL Server 

Noticed recently that even though the SQL server job is less than 100GB it takes more than 1 tape to get the backup for that server completed, and the 1 server with >1TB of data takes 3+ tapes

I have tried doing 1 job for all 4 servers, which cut down the tapes but stuffed up the daily differentials, so reverted to individual jobs to ensure we have a proper differential job each day

Could I run the 1 job for all servers as the full backup, then the 4 seperate jobs for the daily differential?



Employee Accredited Certified

You gave to link differentials with the full so no you cannot split in the way you ask.


With regards your tape handling

1) Are you using a library and is yes how many drives has it got?

2) Do you start the 4 separate backup jobs at the same time?

3) Do you know if the first tape used by each of the 4 jobs is being overwriteen or appended to  (the job logs should show this)?




Are your tapes getting marked as "media full"?  Or are your tapes not getting 100% full?

If they are truly getting full, then the focus is on the data source, compression, etc.  if they are getting 100% full, but actually holding less data than the native LTO4 capaity, then you may have a clogged tape drive head.  See

If they are not getting 100% full, then the focus is on your job strategy (timing, append vs overwrite, as Colin mentioned)


Hi Colin,

Thanks for replying, in answer to your questions

1. We use a library with 2 banks, 24 slots and 1 drive

2. Yes, I stagger the jobs an hour apart, which used to work fine and used 4-5 tapes, but has now gone to 6-7 tapes with the same amount of data being backed up

3. The jobs are set to Append to media, overwrite if no media is available

Hi Larry,

The media says ifs full and uses 780GB of 781GB available, just running the cleaning tape through a few times now, plus will chuck in a new cleaning tape and see if that changes things

Thanks for the help

Level 2

By way of update, ran the cleaning tape 5 times before the full backup jobs kicked off this past weekend and still having dramas with too many tapes

My manager is going to order in a new cleaning tape, so I will try that as well

Otherwise things are looking shady still