What exactly is the role of "Device Reserve By Media Type" setting?

[Tomi Pozderec]

I can't find any info for this setting in the documentation (https://docs.bareos.org/).

I've read that enabling this setting is required for successful consolidations. My question is - why?

Let's take the two examples below:

1.

• two devices are defined in /etc/bareos/bareos-sd.d/device to be used for consolidations (same Media Type)
  
• one storage resource is defined in /etc/bareos/bareos-dir.d/storage and both of the above devices are added to it
  
• there's one consolidation pool defined in /etc/bareos/bareos-dir.d/pool/ and the above storage is added to it

What is the effect of `Device Reserve By Media" set to `yes` or `no` in this scenario?

2.

• Same as above, but there's only one device defined in /etc/bareos/bareos-sd.d/device to be used for consolidations

What is the effect of `Device Reserve By Media" set to `yes` or `no` in this scenario?

Thanks!

[Marco Betschart]

Would love to know more about the "Device Reserve By Media" too, because I'm struggling with the Always Incremental Consolidation and there seems no complete documentation available about this flag atm.

[Dan]

Tomi / Marco -

Please take a look at this thread.

https://groups.google.com/forum/#!searchin/bareos-users/cushing%7Csort:date/bareos-users/UGSb302dMqM/gwd4i7JLBAAJ

Dan

[Tomi Pozderec]

Hey Dan,

Thanks for the reply. I've read that, but it still doesn't go into a lot of details.

Also, my experiences contradict this statement: "Without this setup [`Device Reserve by Media Type = yes`] the AI-Consolidate job cannot simultaneously read and write from the same pool."

We are using Bareos 18.2 and we didn't configure `Device Reserve By Media` Type settings. Which means it is set to default, which is "no".

We are using two devices per `Archive Device [type: folder] with same `Media Type`. Our consolidation works. This means one device is reading from a single pool and another is writing into it simultaneously (without `Device Reserve By Media Type = yes`).

Is `Device Reserve By Media Type` really required?

[Dan]

I'll defer to others, then.  My comments were based on Bareos 17.2.  Perhaps 18.2 behaves differently.  I'm no longer actively administering Bareos, so I don't have an 18.2 to look at.  Sorry I couldn't be more help.