Backup needs 2 tapes: append, then overwrites next tape

[ofo]

Hello

Ik have a data backup that writes to a pool of 7 tapes.When my backup starts, it append to tape 1 on monday. On tuesday, the tape 1 has not need enhough space left over, so you should think it appends, for example, too tape 4 which shows 100 gigs free. But instead, BE decides to take the next one in row, tape 2, which he overwrites.

although, my media set is set on "infinite-allow append". overwrite is set to 1day because i i wanted BE to append as much as possible, and then start to overwrite.

I presumed BE would search a tape to append to, instead of just taking the next one & start to overwrite.

Is this by design, of do i need th change my media set so BE looks at the tapes in his pool and takes the one with appendable space?

thanks is advance!

[pkh · Accepted solution]

This is by design.  BE will append to the first tape and then overwrite the second and subsequent tapes.

[ofo]

Thank you. Can i modify this by changing my media set setting or not?

[pkh]

No. You can't. 

[ofo]

Suppose that i set my overwrite protection period to 14 days, what will BE do? he can't take the next one, because i won't allow it to overwrite it.
That way, won't he get to tape 4 and append?
Or will i end up with a failed job?

[pkh]

BE will NOT append after the first tape.  If it cannot find an overwriteable tape, it will prompt for one.  Since you are using a library, there is no way to put in an overwriteable tape, so you will have the fail the job.

[ofo]

I forgot to mention someting: when tape 1 is full, tape 2,3 & 4 are tagged as: not appendable (media full), but of course overwritable.
why does he takes tape 4 to start his overwrite and not tape 2 for example, the next one in row? they are tagged just the same. In what way does BE decides the tape he takes to start overwriting?

[pkh]

Normally the oldest recycleable tape is used first.

[ofo]

is this the same as modified date when i look at the properties of the tape?

[pkh]

When the tape becomes overwriteable, there is only the allocated date left.