Hello, Thanks for pointing out the misleading information in the manual. That particular paragraph is very old (version 1.39.28 dates from *many* years ago). I will update it to refer to "50GB or larger". I will also correct the sentence about Bacula not being able to seek -- it in fact does seek within a volume to do restores, so the overhead of large volumes for restores is negligible.
My own preference is for volumes from 50G to 500G. There are several downsides of having very large volumes: Downside of large volumes: 1. If the volume gets corrupted (extremely rare) you can lose more data. 2. A really big Volume (500GB or more) is harder to move (storage offsite, ...). 3. A Volume cannot be recycled until *all* the records in it have expired (i.e. reached their retention periods). The bigger the volume, the longer it will contain valid records. Downside of small volumes: 1. Bacula's code for handling Volumes in the Catalog is designed for a small number of records (say 10,000 or less). 2. The more volumes you have the longer it will take Bacula to prune them. Best regards, Kern On 12/25/2015 01:21 AM, Peter Keller wrote: > On 12/24/2015 02:16 PM, Kern Sibbald wrote: >> Well, 4GB Volume size seems very small to me. I would start with >> something like 50GB and possibly make them bigger if there are more than >> a few thousand Volumes. > The manual is sometimes ambiguous about things like a good Volume size. > I chose 4GB because of this passage in the manual from here: > > http://www.bacula.org/7.2.x-manuals/en/main/Basic_Volume_Management.html > > "Note, if you use disk volumes, with all versions up to and including > 1.39.28, you should probably limit the Volume size to some reasonable > value such as say 5GB. This is because during a restore, Bacula is > currently unable to seek to the proper place in a disk volume to > restore a file, which means that it must read all records up to where > the restore begins. If your Volumes are 50GB, reading half or more of > the volume could take quite a bit of time. Also, if you ever have a > partial hard disk failure, you are more likely to be able to recover > more data if they are in smaller Volumes." > > I don't know if versions after 1.39.28 can seek in the Volume properly > or not. > > I don't have a good sense of how big Volumes should be when doing > disk backups. > >> The error: >> >> 23-Dec 18:47 DIR:xxx.yyy.zzz JobId 4: Error: Catalog error updating file >> digest. bdb.h:101 Update failed: affected_rows=0 for UPDATE File SET >> MD5='oGhRwHZ+y+mWb+fv9ppFrA' WHERE FileId=6148914691236517205 >> >> Is not something that is "fatal", because having the MD5 in the catalog >> is not critical, but it indicates a real problem. The FileId is clearly >> wrong, and possibly indicates a bad build or some strange bug due to an >> unusual configuration. I would be interested to know if you know how to >> reproduce it. > The only way I seem to be able to reproduce it is if I'm backing up > a fileset which is larger than the target Volume (like / on a 20G > machine with 4GB Volume sizes) each time the Volume gets filled and > a new one created I get that error. If under other conditions a new > Volume is chosen, like the volume reached its Jobs limit or volume > use duration, I don't get the error. It may also be the case that > there is an individual file which is larger than a Volume that spans > into a new Volume too. I didn't think I did anything particularly > strange in the configuration files, but since I'm new to Bacula, > I may have done it without realizing it. > > I'd be happy to open up a bug report at http://bugs.bacula.org > if you'd like and upload config files and other information like > platform (Debian Linux 8), database backend (Postgresql 9.4), what > compiler built Bacula (gcc version 4.9.2 (Debian 4.9.2-10)), and how > I configured Bacula (I have a lot of ./configure args...). > > Thank you! > > -pete > > ------------------------------------------------------------------------------ _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
