On 2014-11-19 08:52, Ana Emília M. Arruda wrote:
>>> Do you have "prefer mounted volumes" set to no in your jobs
>>> definition? It is recommended if you are using multiple devices
>>> and
>>> one pool.
>>
>> I do not have this set because of the warnings against it in both
>> the manual and one of the white papers.
>
> But this is recommended when using multiple devices (autochanger or
> stand alone) and one pool.
>
The warning in the manual sounds quite serious. Is it no longer valid?
Yes, it is still valid. Maybe I was not very clear in my answer. The white papers talk about having this directive set to "no" to spread jobs over multiple devices instead of using maximum concurrent jobs directive when having multiple pools. Because it can lead to this situation: "As this option will try to spread Jobs over all devices, if you are using multiple Pools
in your backup strategy, all devices can be busy writing to Pool A, and other Jobs
that want to use something else will wait for a free slot. " (from the whtie paper).
I'm supposing you have scheduled jobs in a way that they will use just one pool in a specific day. So all of your jobs will use volumes in just one pool and, in this case, the prefer mounted volume directive set to "no" is recommended, I'm not sure if you had a took at the manual:
"If the directive is set tono, the Storage daemon will prefer finding an unused drive, otherwise, each job started will append to the same Volume (assuming the Pool is the same for all jobs). Setting Prefer Mounted Volumes to no can be useful for those sites with multiple drive autochangers that prefer to maximize backup throughput at the expense of using additional drives and Volumes. This means that the job will prefer to use an unused drive rather than use a drive that is already in use.
Despite the above, we recommend against setting this directive to no since it tends to add a lot of swapping of Volumes between the different drives and can easily lead to deadlock situations in the Storage daemon. We will accept bug reports against it, but we cannot guarantee that we will be able to fix the problem in a reasonable time.
A better alternative for using multiple drives is to use multiple pools so that Bacula will be forced to mount Volumes from those Pools on different drives."
Have you tried to set it to no just to notice if the problem of the second job waiting for the volume still occurs?
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