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Overwrite tape with insufficient space for job, append if enough space?

rablack
Level 4

Hi all,

I have an LTO-5 tape drive and daily/weekly/monthly full backup jobs of around 300GB. It is not essential, but if possible I would like for daily tapes to be only overwritten if the next job will not fit. So for instance Monday week 1, 2 and 3 fit on one tape. This way I get three weeks of daily archive data and disaster recovery to any point in time.

Monday 4 would cause the tape to be overwritten because prescanning says it won't fit. Currently I do not think this will be the case and the job will start appending to the almost-full tape and then ask for more media. There is no option to change a tape if the current one becomes full, as backups must run during non-office hours to avoid performance issues. There is also no option to buy any additional hardware.

Obviously, in this scenario on Thursday of week 4, I only have one week of archived dailies, but if this also applies to the weekly and monthly backups, then I will have a much longer archive retention ability with the same number of tapes. Or am I overcomplicating things?

Thanks,

Richard

 

1 ACCEPTED SOLUTION

Accepted Solutions

Kiran_Bandi
Level 6
Partner Accredited

which would allow for 3 jobs per daily tape to be written before the tape becomes overwriteable only

For this to happen you have to set the Overwrite Protection period also accordingly. 22 days Append period with 6 days OPP would be the ideal/safe settings. I presume that you will be inserting moday tape on mondays week1, week2...... manually. Otherwise other backups will be appended to monday tape becuase of 22 days AP, if you have only one media set defined for daily backups. Hope i am not confusing you further...

Design the retention settings for other backups also and proceed. (As you said, tweak the AP setting after checking how many backups can fit into one tape)

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2 REPLIES 2

rablack
Level 4

Ok, so what I am now going to test is setting my append period to three weeks, which would allow for 3 jobs per daily tape to be written before the tape becomes overwriteable only. If the size of the jobs increases so that less than 3 will fit, I will have to change the append period. Obviously, a method that does not require manaual intervention and monitoring (and potentially a failed job) would be preferable.

Any ideas?

Kiran_Bandi
Level 6
Partner Accredited

which would allow for 3 jobs per daily tape to be written before the tape becomes overwriteable only

For this to happen you have to set the Overwrite Protection period also accordingly. 22 days Append period with 6 days OPP would be the ideal/safe settings. I presume that you will be inserting moday tape on mondays week1, week2...... manually. Otherwise other backups will be appended to monday tape becuase of 22 days AP, if you have only one media set defined for daily backups. Hope i am not confusing you further...

Design the retention settings for other backups also and proceed. (As you said, tweak the AP setting after checking how many backups can fit into one tape)