Forward incrementals and VBK 'bloat'

[slidek9]

Hiya,

With the v4 version, when using reverse incremental, the synthetic full used to grow all the time, with unreferenced datablocks not being deleted - but being able to be overwritten when needed - this was a bit of a pain when replicating offsite as un-needed blocks are prime for replication. The only way to clean up the vbk was to run a Full Backup.

Now with v5 and (forward) Incremental and 'Enable Synthetic Fulls' - does this mean then the new synthetic full is constructed there is no longer any 'bloat' and the full only contains active data blocks?

Cheers!

[Vitaliy S.]

Yes, that's correct.

[Gostev]

There is no magic or anything, you just cannot reduce a file in size without recreating it, this is how most file systems work. In v5, with incremental backup mode synthetic full process creates new file (using only active blocks). So the idea is really no different from initiating a Full Backup in v4, which you had to do before. The only difference is that you no longer need to do "active" (real) full backup to achieve that.