Auto Changer device/volume names

[Gregory West]

From what I have seen, when backing up to a harddrive the 'Device' is the folder where the volumes are going to be placed.   The 'Pool' is a group of harddrives that can be used. The Volume is the file containing the actual backup.

When it comes to an Auto Changer tape drive I get a little more mixed up.  From what I am seeing the 'Device' is the actual tapes themselves (named by bar code) the 'Pool' is a group of tapes assigned to a job stream. and the Volume is the file containing the backup.

First question, is this more or less correct?

Second question has to do with pools, and their use.   I am assuming bareos can add more volumes to the end of an existing backup tape (ie three full jobdefs on one tape)  A tape will only be reused after the last volumes retention time has expired.  If the tape in this case returned to scratch pool?  Can I force a job to start on a clean tape?  ie the first monthly job is always at the beginning of a tape followed by the second, third full backups.

If so how do I instruct bareos to start a new tape?

Last question, I am assuming 'Differential' does not reset the backup/archive flag on a file, but Full and Incremental do.    Is this correct?

Also done all my work, when its running I will be posting my .conf files for anyone else to reference them.   Will also do a short-ish write up on the hurdles I went through getting the autochanger to work.

Greg

[Spadajspadaj]

No. A Volume is a... volume. A single storage entity. It might be a tape, it might be a file. Single volume can hold a part of a job (if the job is sufficiently big to span several volumes), a single job (especially if you set an option to use separate volume for each job) or multiple jobs.

Typically when using disk-based storage, people often use one volume per one job setting because it's easier to maintain the volme files this way. But in case of physical tapes, it's just that one tape is one volume. And you can have the same with disk-based backups - you can for example create pre-allocated volume files of given size and treat them as you'd do with physical tapes - it simplifies volume management in other cases, like when using multiple disks and vchanger. So the sentence "add more volumes to the end of existing tape" makes no sense. Bareos can write more jobs to the end of the existing volume as long as it's in appendable state.

MK

--
You received this message because you are subscribed to the Google Groups "bareos-users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to bareos-users...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/bareos-users/aa8e403b-6b9f-4f13-be45-3e69760060afn%40googlegroups.com.

[Gregory West]

So let me see if I have the correct.    A volume can contain the data from more than one job, and a job may contain more than one volume.  This changes how I will have to think about things for tape backup.    One issue I am having and where my confusion probably started.  The volumes on my tape backup seem to be coming from somewhere (not figured out where yet) and not taking on the name of the tape (They are all barcoded)  Can this be changed?

Be nice if the volumes and the tape names were the same.   Which would bring up the second issue how do I go about stating the volume sizes etc?  This is on an LTO5 tape drive.

[Spadajspadaj]

Yes. Depending on the configuration - yes, a volume can store data from multiple jobs (and not necessarily from the same client!), and yes, a single job can span several volumes.

The storage definition is a bit... convoluted in bareos. The Storage resource in director's config references a Device resource but this one is defined on the SD side and director only "uses" it. It doesn't have much knowledge about physical properties of the device. So it's the SD config which will have the definition of the hardware device.

Also tapes are usually _not_ automatically labeled. You label them manually either explicitly or using the "label barcodes" command.

So in your case the tapes must have been labeled historically by someone who didn't keep the labels of the volumes consistent with the barcodes.

You can relabel the volumes but they have to be in the Purged or Recycle state (not "actively" used). And I don't see a way to relabel using barcodes.  There is another brute-force way of removing old labels but it's not pretty and can leave traces of old volume definition in directory. But then the volume is treated as "clean" and can be labeled anew. Possibly using "label barcodes".

MK

To view this discussion visit https://groups.google.com/d/msgid/bareos-users/c007ea9a-5eb8-4405-8569-620020ad08f5n%40googlegroups.com.