What gets re-written if you need to expire a tape early?

[pkelly_sts]

Given a media pool with a 4 week retention and the oldest tape has a synthetic full & a mix of a few days of incrementals but isn't due to expire for another 4 days, if I desperately need some tape space for a new backup pass and mark as free the oldest tape, I know that it should re-copy the "missing" incrementals to tape again, but what happens about the full, does it re-generate a synthetic full from that date?

Further information: I started with a plan that had a tape-per-week (containing full backup + 6 incrementals) by creating a new media set each saturday. I've changed my mind on how I want to manage tapes and decided that just spanning all available tape space is better (for us) than wasting 1.4Tb/tape each week.

This week I might be a little tight on space so would like to have a tape "in-hand" just in case but as it's a remote site I can't get another physical tape there in time so am considering re-using the oldest tape for now, hence the question.

[Shestakov]

Hello Paul,
Could you give more info about the source(disk) and tape jobs schedule? Also what option of new media set creation do you have?

Further information: I started with a plan that had a tape-per-week (containing full backup + 6 incrementals) by creating a new media set each saturday. I've changed my mind on how I want to manage tapes and decided that just spanning all available tape space is better (for us) than wasting 1.4Tb/tape each week.

If you create a new media set once a week using incremental source job with synthetic fulls and manually make the oldest tape unprotected it will be rewritten from the beginning, i.e. from .vbk, but since you have 4 weeks of backups on tapes, newer chains on newer media sets will be untouched.
Thanks