[CentOS-virt] What kernel params to use with KVM hosts??

Wed Mar 17 10:56:56 UTC 2010
carlopmart <carlopmart at gmail.com>

Steven Ellis wrote:
> carlopmart wrote:
>> Hi all,
>>
>>   I order to reach maximum performance on my centos kvm hosts I have use these params:
>>
>>   - On /etc/grub.conf:
>>
>>     kernel /vmlinuz-2.6.18-164.11.1.el5 ro root=LABEL=/ elevator=deadline quiet
>>
>>   - On sysctl.conf
>>
>>    # Special network params
>>    net.core.rmem_default = 8388608
>>    net.core.wmem_default = 8388608
>>    net.core.rmem_max = 16777216
>>    net.core.wmem_max = 16777216
>>    net.ipv4.tcp_rmem = 1048576 4194304 16777216
>>    net.ipv4.tcp_wmem = 1048576 4194304 16777216
>>
>>
>>    # Disable netfilter on bridges.
>>    net.bridge.bridge-nf-call-ip6tables = 0
>>    net.bridge.bridge-nf-call-iptables = 0
>>    net.bridge.bridge-nf-call-arptables = 0
>>
>>    # Virtual machines special kernel params
>>    vm.swappiness = 0
>>   
> Care to explain some of your choices.
> 
> In particular why
> 
> vm.swappiness = 0
> 
> and why elevator=deadline over noop.
> 
> Steve
> 

I use elevator=deadline on kvm host. Under kvm guests I use elevator=noop ...

vm.swappiness is heredated from vmware installations. Is it wrong??


-- 
CL Martinez
carlopmart {at} gmail {d0t} com