CPU is a pretty poor measure of performance to the user workload..but it depends(tm) what you wanna do.

Do you think HA is to provide a 100% seamless service where there is zero impact.
-or-
Do you think HA is to provide services in the case of a failure, where there may be additional latency, but you are _still working_.


Either way, consistent HA testing (yearly?) will help you track the resiliency of your HA solution...because honestly CPU is not the best way to look at this, at least by itself.


On Fri, Apr 4, 2014 at 7:15 AM, Martin <martin@leggatt.me.uk> wrote:
I know that if a Filer is not busy serving data it will run background task
at a higher priority that will use the spare CPU while the Filer is not
under load.

In an active/active config the Filer CPU shouldn't be over 50% on each
controller as above this the Filer is not longer HA.

My question is if a Filer is showing low latency and isn't busy but its CPU
is at 50% on each controller is this an issue?

I'm not clear if you have two controllers showing 40/50% CPU due to
background tasks that isn't busy  whether it will still be HA if one
controller were to fail? My thinking is those background tasks will just run
at a lower level (some may not run in failover state??)





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