CentOS virt - Mar 2010 - What kernel params to use with KVM hosts??

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

  Do I need to configure something more?? Any tips??

  Thanks.

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

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

-- 
Bulletin.net <http://www.bulletin.net/>    *Steven Ellis - Director of
Worldwide Engineering,*
    *Bulletin.Net Inc* - http://www.bulletin.net/
    *Ph* +64 9 307 1146  *Fax* +64 9 307 1148
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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