Availability collection interval defaults
Jay Shaughnessy
jshaughn at redhat.com
Mon Mar 5 16:58:08 UTC 2012
On 2/29/2012 12:22 PM, Jay Shaughnessy wrote:
>
> In [most likely] RHQ 4.4 there will be several improvements to
> Availability collection and handling. One of the major changes is
> /Prioritized Availability Collection/.It means plugin developers can
> optimize their types to set out of box availability collection
> intervals. And users can alter the interval at
> template/group/resource granularities. The inherent difficulty, like
> other default metric enablement/collection interval settings, is how
> to decide what the settings should be.Out of box we want to be
> conservative while still being useful.
>
> There are two topics that need discussion, the built-in defaults and
> how to approach the plugin-specific overrides.
>
> _*Built-In Defaults*_
> The current defaults are based on category; server types are set to 1
> minute and service types to 5 minutes.This actually increases avail
> checking as previously everything was 5 minutes. These defaults are
> not set in stone, they are just numbers I picked.
>
> The 1 minute server default aims to increase the avail checking on
> types that are more likely to be important. This affects a small
> percentage of types and so far everyone has informally agreed that
> this seems like a good setting. Of course plugin descriptors can
> override the default.
>
> The 5 minute service default simply maintains the default avail scan
> period from earlier versions, giving a nod to backward compatibility.
> This setting can easily be debated. Increasing the default to, say 10
> or 15 minutes, would give immediate performance benefit out of box.
> As the majority of resources would be checked less often. This
> raises a few fundamental questions: Is slow avail checking even
> useful? is backward compatibility even relevant here? Is a slow
> default a good idea seeing that plugins can easily override the
> defaults, and users can further optimize their settings?
The more I think about it the more I like the idea of a 10 minute
Service default. This gives us a blanket performance enhancement out of
box, without, I think, much of a functional difference over a 5 minute
default. Plugin developers can override this on any types they see fit.
And of course users can then customize intervals further, any way they
see fit. In the end I would think that resources the plugin developer or
users consider critical, would be assigned intervals less than 5
minutes. I think perhaps the best scenario is a small number of
relevant resources with fairly short intervals, and the rest with larger
intervals.
>
> Note also that availability collection can now be disabled on a type,
> out of box. Which means that it will immediately be assigned the
> avail of its parent. This is likely appropriate for any component
> that simply returns UP in its getAvailability() implementation.
>
>
> *_Plugin-specific Overrides_*
> To be clear, it is a goal that our most critical plugins be optimized
> out of box to better today's performance, increase avail checking for
> the most important resources and lessen or disable avail checking for
> less important resources. The question is, who knows what these
> settings should be? How do we go about making these setting changes?
>
> Please chime in with your thoughts.
>
> _______________________________________________
> rhq-devel mailing list
> rhq-devel at lists.fedorahosted.org
> https://fedorahosted.org/mailman/listinfo/rhq-devel
More information about the rhq-devel
mailing list