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Span on to an appendable tape

Created: 23 Aug 2011 | 5 comments
be-nugget's picture
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This is something that has caused me headaches for some time now and I have read the official comment from Symantec saying a job cannot span on to an appendable tape, and has to be overwritable.

Being able to use the space on tapes which have already been appended to would be a god send especially when you have backups that are bigger than the tape media and only have appendable media available in the library when it needs to span to another tape.

Could this functionality be considered in future versions or is there a technical reason for this not being possible?

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pkh's picture

Everytime you append to a tape, the OPP is re-calculated from the end of the appending job.

Suppose you are using 800GB tapes and your OPP is 7 days.  There are 3 tapes with 100GB of free space left on them.  They would be overwriteable in 1 days time,  This means that in 1 day's time, you would have 2.4TB (=3 x 800GB) of space.  If it is possible and your job appends to all of them, they would be protected for another 7 days which means that you "loose" 2.4TB for 6 days.  Do you really want this situation?

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Levittown's picture

I do monthly backups on tapes in a seperate partition and media set. There should be a way for backup exec to know that a specific tape was just written to about 30 minutes ago, and that there is 100 GB free on it. I can't tell you how many times I have to put in an overwrittable media for a lousy 30 gb - and the rest of the tape is waasted at that point.

be-nugget's picture

I now understand the issue of OPP.  Seems logical now you have explained it. Thanks.

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Captain Bash's picture

I'm sure the current version (2010 R3 SP1) will append to multiple tapes using the overwrite recyclable media first (media management in main options) option along with append to media, overwrite if no appendable media is available (option in tape job policy)

This is only really ideal if you run more than a few jobs at the same(ish) time - ie over a weekend. You can set the append period to 3 or 4 days, with overwrite protection - they will then be appended to, but the original data not overwritten.

In this scenario, the first 2 jobs may use two overwritable tapes. the next job may then fill the rest of the space on the first, and then append the rest of the job to the second.

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Geute's picture

Hi,

2010 R3 SP2 shows the same behavior. In my media set I have an appendable tape with 700 GB free space but the backup job ask for an overwritable tape for the last 30 GB.

Several times I asked Symantec for a change with no luck. 

Is it so difficult to change this? or is there any other reason?

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