Re: [PERFORM] CPU load spikes when CentOS tries to reclaim 'cached' memory

2014-06-06 Thread Merlin Moncure
On Thu, Jun 5, 2014 at 6:57 PM, Vincent Lasmarias wrote: > Thanks for the informative responses and suggestions. My responses below: > > * Sorry for the double post. I posted the original message using my gmail > account and got a "is not a member of any of the restrict_post groups" > response and

Re: [PERFORM] CPU load spikes when CentOS tries to reclaim 'cached' memory

2014-06-05 Thread Vincent Lasmarias
Thanks for the informative responses and suggestions. My responses below: * Sorry for the double post. I posted the original message using my gmail account and got a "is not a member of any of the restrict_post groups" response and when I didn't see it for a day, I ended up wondering if it was due

Re: [PERFORM] CPU load spikes when CentOS tries to reclaim 'cached' memory

2014-06-05 Thread Merlin Moncure
On Thu, Jun 5, 2014 at 2:47 PM, Deron wrote: > We saw very similar issues with a CentOS server with 40 cores (32 > virtualized) when moving from a physical server to a virtual server (I think > it had 128GB RAM). Never had the problem on a physical server. We checked > the same things as noted

Re: [PERFORM] CPU load spikes when CentOS tries to reclaim 'cached' memory

2014-06-05 Thread Deron
We saw very similar issues with a CentOS server with 40 cores (32 virtualized) when moving from a physical server to a virtual server (I think it had 128GB RAM). Never had the problem on a physical server. We checked the same things as noted here, but never found a bug. We really thought it ha

Re: [PERFORM] CPU load spikes when CentOS tries to reclaim 'cached' memory

2014-06-05 Thread Merlin Moncure
On Thu, Jun 5, 2014 at 10:58 AM, Jeff Janes wrote: > This sounds like a kernel problem, probably either the zone reclaim issue, > or the transparent huge pages issue. I at first thought maybe same, but I don't think THP was introduced until 2.6.38...OP is running 2.6.32-431.11.2.el6.x86_6. Maybe

Re: [PERFORM] CPU load spikes when CentOS tries to reclaim 'cached' memory

2014-06-05 Thread Jeff Janes
On Wed, Jun 4, 2014 at 5:27 PM, vlasmarias wrote: > For the past few days, we've been seeing unexpected extremely high CPU > spikes > in our system. We observed the following: the 'free' memory would go down > to > lower than 300 MB; at that point, 'cached' slowly starts to go down, and > then CP