High rate of NFS cache misses after upgrading from 10.3-prerelease to 11.1-release

[Rodney W. Grimes]

[ Charset windows-1252 unsupported, converting... ]
> 15.04.2018 19:58, Rick Macklem wrote:
> 
> > Niels Kobschaetzki wrote:
> > [stuff snipped]
> >> It is a website with quite some traffic handles by three webservers behind a pair >of loadbalancers.
> >> We see a loss of 20% in speed(TTFB reduced by 100ms; sounds not a lot but >Google et al doesn?t like it at all) after upgrading to 11.1 with a combined upgrade >to php7.1. On another server without NFS that upgrade improved performance >considerably (I was told ca 30% by the front end-dev)
> > One thing you could try is booting the 11.1 kernel on an 10.3 system. Newer
> > FreeBSD kernels should work with older userland.
> 
> Though one should remember that some important system utilities
> may and probably will not work with newer kernel, like /sbin/ipfw, route,
> ifconfig, netstat etc.

I thought that as long as the newer kernel has the right
COMPAT_FREEBSD10 compiled in that all this stuff should work.
Am I miss understanding this kernel option?

> 
> > This would tell you if it is kernel changes or userland changes that are causing
> > the higher miss rate.
> 

-- 
Rod Grimes                                                 rgrimes at freebsd.org