[lvs-users] extremely slow (10kb/s) LVS NAT on new RHEL 6 load balancer

Alois Treindl alois at astro.ch
Sat Nov 26 14:46:04 GMT 2011


I am setting up a new LVS NAT load balancer, running on Redhat 
Enterprise Linux 6.

I have been runnign LVS NAT on RHEL for many years, our current load 
balancer is on RHEL3, which isno longer supported by Redhat.

I have a very strnge problem: performance of http through the LVS is 
extremely slow at something like 10 kbyte/sec, ridiculous.

I have made two approaches for the setup, but arrive at the same problem.

kernel:  2.6.32-131.17.1.el6.x86_64
ipvsadm-1.25-9.el6.x86_64  from Centos 6 (becaus my subscription for 
RHEL6 does not include the load balancing)

Approach a)
I used my own old scripts based on ldirectord, ipvsadm and iptables
to configure and administer my setup as I did on my old LVS.
It worked, but as I said, extremely slow. 10 kByte/second !!!!

For the moment, I only set up http

Approach b)
I installed piranha-gui  (piranha-0.8.5-7.el6.x86_64, also from centos6)
and configured the NAT lvs with it.

The simple setup looks like this:
TCP  (my virtual ip):http wlc persistent 60
   -> w2:http                      Masq    1000   0          0
   -> w3:http                      Masq    1000   0          0
   -> w4:http                      Masq    1000   0          0

Routing in the NAT LVS is:
Kernel IP routing table
Destination  Gateway    Genmask         Flags Metric Ref    Use Iface
192.53.104.0 0.0.0.0    255.255.255.128 U     0      0        0 eth1
10.1.1.0     0.0.0.0    255.255.255.0   U     0      0        0 eth0
0.0.0.0  192.53.104.62   0.0.0.0         UG    0      0        0 eth1

routing in a real server is:
Destination  Gateway   Genmask         Flags Metric Ref    Use Iface
10.1.1.0     0.0.0.0         255.255.255.0   U     0      0        0 em1
0.0.0.0      10.1.1.254      0.0.0.0         UG    0      0        0 em1

currently empty iptables:
iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination
Chain FORWARD (policy ACCEPT)
target     prot opt source               destination
Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

ip6tables dito

Is something broken in RHEL6 regarding LVS NAT use?
Or am I doing something stupid without noticing?

I need to get this thing running over the weekend, but am running 
against a wall!





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