Hi Jeff,
I ask as we have a Filer that isn't experiencing any performance issues from the client perspective but is showing each controller over 50% intermittently. I'm not clear if this is because the Filer isn't busy and is doing background tasks or if it is genuinely busy (perfstats just show the Kahuna domain busy).
In the past Netapp have said that if both controllers CPU is over 50% then the Filer is not HA and an upgrade should be considered (obviously they want to sell Filers)
As you said it's not possible to confirm if this is an issue without failing the controller over and confirm if there is any latency issues on the clients.
I just think its incorrect to say a Filer that has both controllers over 50% CPU intermittently is not HA and requires an upgrade.
In my environment HA is to provide a 100% seamless service where there is zero impact but its difficult to justify testing this on a production system.
Martin
On 04/04/2014 18:17, Jeff Mohler wrote:
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 mailto: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??) -- View this message in context: http://network-appliance-toasters.10978.n7.nabble.com/CPU-usage-and-HA-tp25641.html Sent from the Network Appliance - Toasters mailing list archive at Nabble.com. _______________________________________________ Toasters mailing list Toasters@teaparty.net <mailto:Toasters@teaparty.net> http://www.teaparty.net/mailman/listinfo/toasters--
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