Synthetic fulls on disk needed when tape is used?

[JaySt]

using B&R v8u2.

I've got a local disk repository holding about a month worth of restore points, using forward incremental. I also have synthetic fulls enabled to be created on saturday.
Besides disk, tape is also used for long term backup storage. The tape job is set to copy fulls and process incrementals as well.
I'm not sure what will happen regarding virtual synthetic fulls on tape in this case. It seems to be "on" by default and cannot be disabled.

two questions:
Having synthetic fulls enabled on disk, what is the virtual full to tape behavior like in this case? (is it different behavior compared to when synthetics on disk would not be enabled?)
Does it make sense to enable synthetic fulls on disk at all actually?

[Shestakov]

Hello Jeffrey,

Having synthetic fulls enabled on disk, what is the virtual full to tape behavior like in this case? (is it different behavior compared to when synthetics on disk would not be enabled?)

Virtual Full are produced only if you use backup copy job or forever incremental backup job as a source of the backup-to-tape-job.
Since you have synthetic fulls, you can`t "enable" virtual full backups.

Does it make sense to enable synthetic fulls on disk at all actually?

It depends on your capabilities and needs. Currently we consider forever-incremental mode + surebackup for recoverability as the best practice.
Thanks!

[JaySt]

ok, that's clear.
I went on and created a backup copy job to a secondary disk location and started a tape job from there with the source of the tape job being the copy job (the secondary disk repository).
Although synth fulls were enabled on the backup jobs pointing to the primary repository, at the secondary location virtual fulls were created as shown in the tape job progress window of the tape job on the secondary site...
Should there be a difference in virtual full processing when source is a back-up job versus a copy job as a source?

[JaySt]

Hello Jeffrey, Virtual Full are produced only if you use backup copy job or forever incremental backup job as a source of the backup-to-tape-job.
Since you have synthetic fulls, you can`t "enable" virtual full backups.

thanks! did not see your reply until i posted mine.

[Shestakov]

Note that backup copy job always produces forever incremental backup chains, just like the incremental backup job without full backups scheduled. The behavior of the backup to tape job will be same for these two.
If you use any other job as a source of backup-to-tape, no virtual fulls will be created.
Thanks!