High sustained CPU utilization

Topics: User Forum
Dec 2, 2009 at 7:27 PM
Edited Dec 2, 2009 at 7:29 PM

I have SharedCache (version 3.0.5.1) with replicated caching installed on 3 servers (Dual quad-core processors, 16 GB RAM).  It appears to work without issue for 6-24 hours.  The typical CPU utilization on all three servers during that initial period of time is 2-3% and the utilization appears to be distributed across all cores.  Eventually, the CPU utilization on 2 cores of 1 or 2 servers (it's not always consistent) hits 90%+ and will be sustained until the SharedCache service is restarted.  The other server(s) continue to run at 2-3% CPU.  There otherwise don't appear to be any adverse effects, but I'm curious if anyone else has seen this behavior... or if you have any suggestions to troubleshoot further.

Otherwise, SharedCache has been great... we saw an 80% improvement in home page response time after implementing it.  Thanks for the great work!

Greg

Oct 26, 2010 at 2:31 PM

Hi,

We run load balancing on 6 blade servers and are experiencing the same problem.

Version 3.0.5.1 as well

Nov 10, 2010 at 4:14 PM
Edited Nov 10, 2010 at 4:14 PM

Has anyone found a solution to the high CPU utilisation yet? I'm running shared cache currently as a single cache server for 3 webservers. After a week or so usage when our client sends out an email shot (resulting in rapid growth in the number of visitors) sharedcache locks out the CPUS and starts eating memory. This causes the app to hang until shared cache is restarted (at which point its all fine again). Cache server is a dual qaud core xeon with 4 GB ram. Normally around 2000 cache items of around 50mbs size. Version is 3.0.5.1.

Aaron

Jan 10, 2011 at 2:09 PM

More nodes required, i had simalar issues under heavy traffic i increased the number of nodes which fixed it.

Jan 10, 2011 at 4:37 PM

That makes sense, links with the bug in our code that was requesting a cache key from the shared cache many more times than it should have been. This was generating an extra 10-200 cache hits per page load which was I guess swamped the cache node. Since fixing this sharedcache has been great and uses only a few % of the CPU.

Jul 5, 2011 at 7:37 AM
Edited Jul 5, 2011 at 7:43 AM

Fryedfish, what do you mean under "more nodes required"? I had the same problem - on the web server there is sharedcache installed and running. After some hours of work the load of the CPU grows to 90%+. Would you advice me if I am wrong should web.config contain all except server configuration? I mean client, nlog and notify configuration sections.

Mar 7, 2012 at 1:41 PM

By more nodes i mean more server instances.  If you overload any one server it effectively crashes and you get high processor usage behaviour.  Also be careful to not over fill each server instances.  As soon as the Garbage collector gets agressive ( low memory conditions) the processor spends most of its time in GC.