Hello, I'm a bit burned out from intensive bug fixing over the last couple of months, so decided to do something totally new yesterday. I started implementing what I call Virtual Backup or Vbackup, which is essentially project #3 "Merge multiple backups (Synthetic Backup or Consolidation)".
In attempting to implement it, I've realized a few things: 1. It is probably better to implement it as a new "level" under the normal Backup code, for example "level=vbackup". The resulting output will be recorded in the catalog as a "Full". 2. In most all respects it must behave much like a Migration job in that it does not use a FD, it reads an existing set of backups, and writes them to a new Volume. 3. One difference from a Migration job is that all the old jobs remain unchanged (i.e. like a Copy). 4. Another difference is that it has many fewer features in that it simply finds all the current backup records and copies them. There are no complicated selection criteria. 5. Like the Migration and Copy jobs, the input Pool (from where it reads the currently backed up data) and the output Pool (where it writes the merged data) must be different. This ensures that the job does not attempt to read and write to the same device, which just will not work. Well the problem with the above -- principally item #5 is consider the following: You have a job J1, which does a Full, one or more Diff backups, then any number of Inc backups all going to Pool P1. At some point in time (possibly via the Schedule), you run a vbackup level, so it finds all the current backup files (Full, last Diff, and all later Inc) and copies the data from the input Pool (P1) to the output Pool (P2). Now, if you then redo a normal Full backup and restart with Diff and Inc jobs again, all will work. However, it is much more likely that you will then continue doing incremental backups (no more Full or Diffs). At some point later, you want to do another vbackup to "consolidate" all the Inc backups, and now the process fails, because you are going to need to read from Pools P2 (Full produced by the vbackup) and P1 (new Incs), and you will attempt to write to P2, which will not work. Thus without some other mechanism to move Volumes from Pool to Pool, a setup like described above won't work, and I suspect this is what will be done the most frequently (i.e. do only one Full and there after vbackups when there are enough Incs to warrant a consolidation). Any comments? ------------------------------------------------------------------------- Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 _______________________________________________ Bacula-devel mailing list Bacula-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-devel
