On 2014-11-15 20:45, Kern Sibbald wrote:
> Unfortunately, I no longer have the time to help people debug usage
> problems, which I actually enjoy doing, but the other users on this
> Bacula email list should be able to help you resolve this. I do have a
> few remarks:
>
Thanks for taking the time.
> 1. There is no reason to set the VolumePoolInterval to anything other
> than the default, especially for disk volumes. Doing so could cause
> the
> SD to consume a lot of unnecessary CPU time if there is an outstanding
> mount message.
>
Understood. It was in one of the white papers so I was trying t to see
if it made any difference.
> 2. Forcing Bacula to use only one concurrent job per drive is not
> making
> best use of your hardware. In general, unless you have special needs
> (security, tight restore SLAs,...), it is *far* better from operational
> and performance standpoints to let Bacula write multiple simultaneous
> jobs on a single drive (perhaps 5-10). This will permit the OS to
> reduce disk head movement.
>
Understood. This was for testing. In production I was intending to
start this out at 4-5 and going from there.
> Unfortunately neither of the above points will resolve the problem you
> are seeing.
But good to know none the less.
>
> While you have provided some important input, what is missing is the
> job
> log output including the mount message and a listing the volumes known
> to the catalog DB (list volumes).
>
Ok. I didn't think of sending those. I still have the job log
messages, but the catalog is no longer the same.
> To reassure you, although I have not explicitly tried or tested writing
> to multiple disk drives using some of the techniques recently discussed
> on this list, I am 100% sure that the Virtual Autochanger code does
> work
> exceptionally well with a single disk drive as is your case, providing
> you really have labeled volumes that are available.
>
Ok that is good to now. I was wondering if I was attempting to do
something strange. It wouldn't be the first time. But it sounds like it
is worth persevering with
Does this mean that automatic volume creation/labelling doesn't work in
this type of setup, or does that come under "volumes that are available"
provided Maximum Volumes has not bee reached?
> Note, by turning on a debug level of probably 100 to 150 in the
> Director, and possibly also in the SD, you should be able to "see" more
> clearly why the Director/SD cannot find any volumes that are ready to
> use.
>
I hadn't come across the debug stuff before. I will rerun my tests
tomorrow with debug on.
Thanks again.
Mike
> Best regards,
> Kern
>
>
> On 11/15/2014 12:17 AM, Brady, Mike wrote:
>> First of all thanks to Kern and Bacula Systems for making the "Best
>> Practices for Disk Based Backup" and "Disk Back Design" documents
>> available.
>>
>> I have been playing around with the best way for doing concurrent
>> backups for a while and these documents have helped my understanding
>> considerably. Using a Virtual Autochanger in particular seems an
>> elegant way of doing what I would like to do.
>>
>> However, I am seeing some behaviour in my testing that I did not
>> expect
>> and I need some input.
>>
>> At a high level what I am trying to do is use a Virtual Autochanger to
>> write to multiple volumes in the same pool concurrently.
>>
>> At the moment I have two devices limited to one concurrent job each.
>> Which, if I have understood things correctly, means that I should have
>> two jobs running concurrently writing to separate volumes. The
>> schedule
>> below kicks off eight jobs simultaneously with the number of devices
>> limiting concurrency.
>>
>> This issue that I am having is that the first job gets FileChgr1-Dev1
>> and a volume as expected.
>>
>> The second job gets device FileChgr1-Dev2 as expected, but always says
>> "Cannot find any appendable volumes." and issues a mount request.
>> There
>> are multiple purged volumes with the recycle flag set available in the
>> IncPoool pool. Even if there weren't, the pool has Auto Labelling
>> configured and has not reached the MaximumVolumes limit, so there
>> should
>> "always" be a volume available.
>>
>> Other jobs continue to use the FileChgr1-Dev1 as it becomes available
>> while FileChgr1-Dev2 is waiting for a volume.
>>
>> The second job eventually retries on FileChgr1-Dev2, gets an available
>> volume and successfully completes without any operator intervention.
>>
>> After this the remaining jobs utilise both FileChgr1-Dev1 and
>> FileChgr1-Dev2 as they become available as I expected.
>>
>> Is this behaviour expected (I am assuming some sort of race condition
>> at
>> the start of the schedule with multiple jobs trying to get a volume at
>> the same time) or am I trying to do something fundamentally wrong
>> here?
>>
>> My configuration is:
>>
>> Pool {
>> Name = IncPool
>> Pool Type = Backup
>> Volume Use Duration = 23 hours
>> Recycle = yes
>> Action On Purge = Truncate
>> Auto Prune = yes
>> Maximum Volumes = 50
>> Volume Retention = 2 weeks
>> Storage = FileStorage01
>> Next Pool = "IncPoolCopy"
>> Label Format = "IncPool-"
>> }
>>
>> Storage {
>> Name = FileStorage01
>> Address = 192.168.42.45
>> SDPort = 9103
>> Password = ***************************
>> Device = FileChgr1
>> Media Type = File01
>> Maximum Concurrent Jobs = 10
>> Autochanger = yes
>> }
>>
>> Autochanger {
>> Name = FileChgr1
>> Device = FileChgr1-Dev1, FileChgr1-Dev2
>> Changer Command = /dev/null # For 7.0.0 and newer releases.
>> # Changer Command = "" # For 5.2 and older releases.
>> Changer Device = /dev/null
>> }
>>
>> Device {
>> Name = FileChgr1-Dev1
>> Drive Index = 0
>> Media Type = File01
>> Archive Device = /bacula_storage/FileDevice
>> LabelMedia = yes;
>> Random Access = Yes;
>> AutomaticMount = yes;
>> RemovableMedia = no;
>> AlwaysOpen = no;
>> Maximum Concurrent Jobs = 1
>> VolumePollInterval = 5s
>> Autochanger = yes
>> }
>>
>> Device {
>> Name = FileChgr1-Dev2
>> Drive Index = 1
>> MediaType = File01
>> ArchiveDevice = /bacula_storage/FileDevice
>> LabelMedia = yes;
>> RandomAccess = Yes;
>> AutomaticMount = yes;
>> RemovableMedia = no;
>> AlwaysOpen = no;
>> MaximumConcurrent Jobs = 1
>> VolumePollInterval = 5s
>> Autochanger = yes
>> }
>>
>> Schedule {
>> Name = "DefaultBackupCycle"
>> Run = Level=Full 1st sun at 00:10
>> Run = Level=Differential 2nd-5th sun at 00:10
>> Run = Level=Incremental mon-sat at 00:10
>> }
>>
>> Thanks
>>
>> Mike
>>
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