zenhub worker how many is too many?

[mwcotton]

I see the ability to have multiple zenhub workers, whats the school of thought on when to add a worker? Is there a log I can look at? Is it a cpu or memory issue? Seems like the more the better, but in the computer world that doesnt always hold true.




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[Chet Luther]

Post by mwcotton
I see the ability to have multiple zenhub workers, whats the school
of thought on when to add a worker? Is there a log I can look at? Is
it a cpu or memory issue? Seems like the more the better, but in the
computer world that doesnt always hold true.

The default configuration is to not use workers at all. What you
should be on the lookout for in this configuration for that would tip
you off to enable workers would be regular "Timeout connecting to
zenhub: is it running?" messages when you attempt to remodel devices
or in other areas.

So now.. now many workers? There's no right answer for every possible
scenario, but there are some good rules of thumb. The first would be
that you never want to exceed the total number of CPU cores minus one.
So on a 4 core box, you wouldn't want more than 3 workers. This is to
keep the web interface responsive.

Maybe more importantly, you could start by enabling 2 workers. Then
you can keep an eye on the size of your zenhub queue. This isn't one
of the standard collector metrics right now, but you can enabled it by
following the following steps.

1. Go to http://yourzenoss:8080/zport/dmd/Monitors/perfConfig
2. Click into the PerformanceConf template
3. Add a new data source. The name is zenhub and the type is Built-In
4. Add a data point to this zenhub data source called workListLength
5. Add a new graph to the PerformanceConf template
6. Add the zenhub_workListLength to this graph.

Now when you click on the Performance tab of your collector you will
be able to see what the size of the zenhub queue has been over time.
You should never see it go over 50, and it should stay below 10 the
vast majority of the time. If this is not the case, you can increase
the number of zenhub workers up to the total cores minus one ceiling
mentioned above.

If you get to this point and your zenhub queue is still too high, your
server likely needs more horsepower.

[James Pulver]

Chet - can I put this in the Community FAQ?
--
James Pulver
Information Technology Area Supervisor
LEPP Computer Group
Cornell University

Post by Chet Luther

Post by mwcotton
I see the ability to have multiple zenhub workers, whats the school
of thought on when to add a worker? Is there a log I can look at? Is
it a cpu or memory issue? Seems like the more the better, but in the
computer world that doesnt always hold true.

The default configuration is to not use workers at all. What you
should be on the lookout for in this configuration for that would tip
you off to enable workers would be regular "Timeout connecting to
zenhub: is it running?" messages when you attempt to remodel devices
or in other areas.
So now.. now many workers? There's no right answer for every possible
scenario, but there are some good rules of thumb. The first would be
that you never want to exceed the total number of CPU cores minus one.
So on a 4 core box, you wouldn't want more than 3 workers. This is to
keep the web interface responsive.
Maybe more importantly, you could start by enabling 2 workers. Then
you can keep an eye on the size of your zenhub queue. This isn't one
of the standard collector metrics right now, but you can enabled it by
following the following steps.
1. Go to http://yourzenoss:8080/zport/dmd/Monitors/perfConfig
2. Click into the PerformanceConf template
3. Add a new data source. The name is zenhub and the type is Built-In
4. Add a data point to this zenhub data source called workListLength
5. Add a new graph to the PerformanceConf template
6. Add the zenhub_workListLength to this graph.
Now when you click on the Performance tab of your collector you will
be able to see what the size of the zenhub queue has been over time.
You should never see it go over 50, and it should stay below 10 the
vast majority of the time. If this is not the case, you can increase
the number of zenhub workers up to the total cores minus one ceiling
mentioned above.
If you get to this point and your zenhub queue is still too high, your
server likely needs more horsepower.
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[mwcotton]

Awesome answer, thanks Chet




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Read this topic online here:
http://forums.zenoss.com/viewtopic.php?p=33548#33548

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