Overwrite / Append Headache

"The jobs start by server 1 appending to the 30% free space, but soon runs out. It promptly stalls there and Library Insert is displayed. It's an append job, so it will not overwrite the recycleable space in tape 1, nor tape 2. Backups failed."

It should overwrite the 2nd tape as if the job spans to the 2nd tape it need an overwritable media (scratch /recyclable) and it should use the 2nd tape, unless another server has already proteted it for a day more.

Both are blue, overwriteable, the full tape is not appendable [full], the second is appendable. The first server appends, when the tape is full, it does not use the recycleable first tape. It just sits there, Library Insert. This made me think that append jobs cannot overwrite? I have no other way of understanding this.

Once the media is full it cannot be appended it can only be overwritten

If the tape is full Backup exec will not overwrite the same tape as it has just filled it up, it will ask you for a new tape. 

For you question append jobs cannot overwrite ?

As you know there are 3 ways using which you can write data to the tape , this is in the job properties

1 If you select overwrite in the backup job, it will only overwrite the tape once the job starts.

2 If you have selected appened else overwrite, it will look for an appendable tape  in the media set that you have selected in the job, if it find such a tape it will keep appending till the tape becomes full

if cant find any it will look for an overwritable tape (scratch/once whose overwrite protection period is over) and will overwrite it 

If there are no overwritable tape available it will display a library insert alert and prompt for inserting an overwritable media

3 Append else terminate

It will only look for tapes which are appendable if it cant find any the job terminates.

Next part is once the 1st tape becomes full and there is more data to write BE will look a tape which is overwritable (may be scratch or recyclable ) , if it cant find any it will again prompt you for that alert

Make sure you keep a tab and know what tapes are overwritable and what are appendable

I do believe I am running into this problem due to overlapping jobs messing with the tapes.

As I said, both tapes are blue when I inventory right before the backups start. That is, recycleable / overwriteable.

It starts to append on the open space on the second tape, but it does not swap to the first tape after the second one becomes full. It will just ask me for Library Insert, the first tape is now suddenly red, along with the second one. 

However, if I quick erase both tapes right before the backups, the jobs run fine with no problems.

...this is by design. BE will not selectively overwrite specific sections on a tape. It's all-or-nothing. That first tape will be protected for 1 day, and that is the WHOLE tape, not a part of it. You'd need a third tape for this.

Thanks!

If you are on BE 2010

Goto tools > Media management > select Overwrite recyclable media.....before overwriting scratch media

In BE 2012

Backup Exec button --> Configuration and settings --> Backup Exec settings >Media management > select Overwrite recyclable media.....before overwriting scratch media

As per the OP's statement:

The jobs start by server 1 appending to the 30% free space, but soon runs out. It promptly stalls there and Library Insert is displayed. It's an append job, so it will not overwrite the recycleable space in tape 1, nor tape 2. Backups failed.

It looks like the OP is trying to selectively erase data on a part of the tape (Tape 1). This is not possible...BE does not do this so the setting above, assuming this is what the OP wants, won't help.

Which explains why, when the OP erases 2 tapes, his backups go through...

Thanks!

Perhaps I was not clear enough, sorry!

Recycleable Tape 1 [Not Appendable [Full]]
Recycleable Tape 2 [70%, Appendable - Infinite]

After appending to the open space on Tape 2, both Tape 1 and Tape 2 are now red [overwrite protected] until the next day.

I check the backup sets, Tape 2 has last week's data [30 July] and the data expires 31 July.
At the bottom, there's a portion of today's [6 August] data [expires 7 August].
Entire Tape 2 is overwrite protected till 7 August.

Tape 1 has last week's data [30 July], and the data expires 31 July.
No other data.
Entire Tape 1 is overwrite protected till 7 August, but no data has been written to it.

I don't understand what I'm missing... 

...is this using the same media set or different ones?

We only have a single media set. 8 servers to 2 tapes a day.

Daily, Weekly, Monthly and Yearly tapes, all in one set. 50 tapes total, all in one media set.