On Thu, Jan 27, 2011 at 08:56:54AM -0500, Phil Stracchino wrote: > On 01/27/11 07:33, Graham Keeling wrote: > > On Thu, Jan 27, 2011 at 06:26:04AM -0500, Phil Stracchino wrote: > >> On 01/27/11 06:12, Graham Keeling wrote: > >>> I think this last problem is what Phil is trying to solve by setting > >>> either > >>> Maximum Volume Jobs or Volume Use Duration. But these solutions seem > >>> unsatisfactory for disks (I can't comment on tapes because I don't know > >>> enough > >>> about them). > >>> You are wasting space if the volume is not full up by the time Volume Use > >>> Duration expires. > >> > >> Define "full". Disk volumes aren't like packing crates. They're more > >> like balloons. They grow as you add data to them. > > > > The idea is to split the disk up into equal-sized chunks. > > In this scenario, you have specified a number of volumes, and a maximum size > > for each volume. For example, on a terabyte disk, you might define 100 > > volumes, > > 10GB each. > > > > If you don't use the "full" 10GB in each volume, the space that you don't > > use > > is wasted. > > No, it isn't. Because it isn't used. If you set maximum volume size to > 10GB, and you create a new volume and write a 5KB job to it, you have > 5KB of data in a 5KB volume, not 5KB of data in a 10GB volume. > > Now, if that volume fills, and gets purged, and you *keep the purged > volume around consuming 10GB of disk space* until it gets reused, well, > then you're wasting disk space, yes. But that has absolutely nothing to > do with what's governing the size of the volume. It is always going to > be the case with any purged disk volume. > > 5.0.3 has a feature to truncate purged disk volumes which gets around > this. But the problem can equally easily be addressed by only using any > given volume once - by whatever means you decide it's "full" - deleting > used volumes as you purge them.
The truncate on purge feature does not work automatically - you have to "do it by hand" - which makes it almost useless. See here: http://sourceforge.net/apps/wordpress/bacula/2010/02/01/new-actiononpurge-feature/ > > You can't use the unused space for some other application, because the > > volume > > might get purged, recycled, and then the next job that writes to it wants to > > use all 10GB - you will then find that it can't. > > This simply neither reflects reality nor makes any sense. I can't even > understand what you're trying to say here. I shall summarise what I thought I had already said, because it is quite clear to me. You have a terabyte disk that you want to use for backups. You split it into 100 Volumes, set 10GB max volume size each, and 1 job per volume. All your backup jobs are 5KB. You can then only use 500KB of disk space before you run out of volumes. You have three obvious options: a) Make more volumes, reduce the max sizes. b) Make more volumes, keep the max sizes the same. c) Increase the number of jobs per volumes. Problems: (a): If you make the volumes too small, you get overhead/maintenance problems. (b): You can easily run out of disk space because you have allocated more than the size of the disk. (c): It becomes very difficult to work out which volumes you can purge/recycle. ------------------------------------------------------------------------------ Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! Finally, a world-class log management solution at an even better price-free! Download using promo code Free_Logger_4_Dev2Dev. Offer expires February 28th, so secure your free ArcSight Logger TODAY! http://p.sf.net/sfu/arcsight-sfd2d _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users