On Friday 20 November 2009 14:44:54 Martin Simmons wrote: > It there a technical reason why the NextPool directive is part of the pool > at all?
It was not really a technical reason, but David Boyes suggested doing it that way, possibly because that is how TSM does it. At the time, I wasn't really sure if that was the best way, but today, I am sure that it was the best way to do what we want (good suggestion David) -- see below for why ... > When I first heard about migration and copy jobs, I expected to > find something like a TargetPool directive in the job definition, so that > it can be varied for each job. Although it would slightly facilitate the configuration in a few cases by allowing a target pool in the Job, it would have some negative consequences, namely that if like many users you separate Full, Diff, Inc into separate pools, it would vastly complicate configurations -- requiring schedule overrides and such. However, Pool and Storage schedule overrides have turned out to be a real pain to get right for a number of reasons -- the most obvious is if a job is automatically upgraded, in general, the schedule overrides will get botched up. If I can, I intend to remove Pool and Storage overrides in the schedules. I think the best place for the Storage definition (suggested by David) is in the Pool, and likewise the best place for the output Storage is through the Next Pool in the Pool definition. Unless I am mistaken, it is just as easy to change the Pool definition in the Job as it is to change what would be Target Pool in the Job. Anyway, that is how I currently see it. If I could see a real practical example why a Target Pool is necessary, I would consider it. One thing that a lot of users may not know is that the Next Pool can point to the current Pool. In the original Migrate implementation this could cause a deadlock reading and writing on the same Volume, but in currently released versions, regardless of the Pool specification and the Next Pool specification is, Bacula should never attempt to read and write on the same Volume. If it does, then I would like to hear about it since I consider that a bug (actually it will be some race condition I didn't foresee in the code). Kern > > Someone already had to hack around this with a dummy pool definition: > > http://thread.gmane.org/gmane.comp.sysutils.backup.bacula.devel/14084 > > __Martin > > >>>>> On Fri, 20 Nov 2009 13:45:06 +0100 (CET), Kern Sibbald said: > > > > Hello, > > > > If the only reason is to prevent a deadlock then this override is not > > necessary since Bacula (at some version, I think it was 2.4.0) will not > > use the same volume for reading and writing. > > > > If there is some other good reason, please remove the comments about > > deadlock and resubmit, and I think you can remove any workarounds you > > implemented to prevent deadlocks. > > > > Kern > > > > > Item ?: Allow Schedule Resource to override NextPool > > > > > > Date: 18 November 2009 > > > > > > Origin: Jim Barber. jim.bar...@ddihealth.com > > > > > > Status: New request > > > > > > What: Allow the Schedule resource to define a NextPool= statement > > > to override the NextPool statement of the pool defined in the job. > > > > > > Why: I have an incremental pool that each week gets consolidated > > > into a > > > full pool via a VirtualFull job. The NextPool directive of the > > > incremental pool defines the location of the full pool. > > > > > > The following week, the next VirtualFull backup will run. It will > > > read the previous full backups and incremental backups since then, > > > to create new full backups. It is important that the VirtualFull > > > backup does not try to write to the same tape that the previous > > > weeks full backup wrote to and left in Append status. Otherwise you > > > could end up with the one tape trying to be read and written and > > > dead-lock. > > > > > > At the moment I have a hack to get around this. An Admin job calls > > > an external command that runs a SQL update to find any tapes in the > > > full pool with an APPEND status and change it to USED. This runs > > > after the full backups have been done. > > > > > > Instead I'd like to create two full pools. One for even weeks and > > > one for odd weeks of the year. That way, even week virtual full > > > backups could consolidate odd week virtual full backups with the > > > latest incremental backups. And the odd week virtual full backups > > > could consolidate the even week full backups with the latest > > > incremental backups. > > > > > > The trouble is that the Incremental pool can only define one Next > > > Pool. I can't have it toggle the Next Pool directive from odd to > > > even, week to week. Unless I could override it from the schedule. > > > > > > Doing that would mean I could ditch my SQL hack to manipulate the > > > tape status. It will also be less wasteful of tapes, since I won't > > > have partially filled USED tapes throughout my library. > > > > > > There are possibly many uses for such an override that I haven't > > > thought about. > > > > > > ----------------------------------------------------------------------- > > >------- Let Crystal Reports handle the reporting - Free Crystal Reports > > > 2008 30-Day > > > trial. Simplify your report design, integration and deployment - and > > > focus on > > > what you do best, core application coding. Discover what's new with > > > Crystal Reports now. http://p.sf.net/sfu/bobj-july > > > _______________________________________________ > > > Bacula-devel mailing list > > > Bacula-devel@lists.sourceforge.net > > > https://lists.sourceforge.net/lists/listinfo/bacula-devel > > > > Best regards, Kern > > > > ------------------------------------------------------------------------- > >----- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 > > 30-Day trial. Simplify your report design, integration and deployment - > > and focus on what you do best, core application coding. Discover what's > > new with Crystal Reports now. http://p.sf.net/sfu/bobj-july > > _______________________________________________ > > Bacula-devel mailing list > > Bacula-devel@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/bacula-devel > > --------------------------------------------------------------------------- >--- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 > 30-Day trial. Simplify your report design, integration and deployment - and > focus on what you do best, core application coding. Discover what's new > with Crystal Reports now. http://p.sf.net/sfu/bobj-july > _______________________________________________ > Bacula-devel mailing list > Bacula-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bacula-devel ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. 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