>>>>> On Sun, 22 Nov 2009 12:16:33 +0100, Kern Sibbald said: > > 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.
OK, that makes sense. > 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. Yes, it is easy to change the Pool in the Job definition, but it seems rather hackish to have dummy Pool definitions just so they can contain the desired Next Pool. > 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. Maybe Migrate and Copy have slightly different requirements? Or perhaps the current design is targeted at scheduled migration and copying, whereas some people want to use it for ad hoc copying? Here is an example: suppose you want to make regular backups of all data for disaster recovery, but also copy some of the jobs to special archive pools. There might be a regulatory requirement to archive emails plus a security requirement to archive traffic logs. The current design makes it difficut to use a single pool for the disaster recovery backups. > 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). Yes, that's nice. __Martin > > 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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