CentOS - Apr 2008 - simple load balancing/failover for OWA

We are building an exchange cluster with two front end Outlook Web 
Access servers.  We would like to at least have some sort of failover, 
and prefereably load balancing for them.

The MS recommended way is to use NLB, but for various reasons that's not 
working with our set up. 

We are looking to set up a single linux server and use something like 
LVS to load balance/fail over the connections. 

Looking at LVS, it looks like it hasn't been updated in a while.  Is it 
stable?  Is it still the preferred solution?  Since OWA has sessions, 
but no session replication, we would need something that can keep 
directing the same client to the same server (either by IP, or 
preferably by cookie).  Can LVS handle this?

I also saw that the latest version of Apache has some sort of load 
balancing support.  Can it be used to set something like this up?  We 
are looking for the simplest solution that won't require a lot of 
maintanence.

We understand that having a single LVS box creates a single point of 
failure, and are willing to accept the risk for now to keep things 
simpler. 

Russ

On Thu, Apr 3, 2008 at 11:07 PM, Ruslan Sivak <rsivak at istandfor.com>
wrote:
> We are building an exchange cluster with two front end Outlook Web Access
> servers.  We would like to at least have some sort of failover, and
> prefereably load balancing for them.
>
>  The MS recommended way is to use NLB, but for various reasons that's
not
> working with our set up.
>  We are looking to set up a single linux server and use something like LVS
> to load balance/fail over the connections.
>  Looking at LVS, it looks like it hasn't been updated in a while.  Is
it
> stable?  Is it still the preferred solution?  Since OWA has sessions, but
no
> session replication, we would need something that can keep directing the
> same client to the same server (either by IP, or preferably by cookie). 
Can
> LVS handle this?
>
>  I also saw that the latest version of Apache has some sort of load
> balancing support.  Can it be used to set something like this up?  We are
> looking for the simplest solution that won't require a lot of
maintanence.
>
>  We understand that having a single LVS box creates a single point of
> failure, and are willing to accept the risk for now to keep things simpler.
>  Russ
LVS is extremely stable.  We have 3 active/passive clusters of LVS
servers, for different projects, and they work extremely well.

The way we set it up was each LVS pair is running heartbeat,
ldirectord and ipvsadm.  If the primary node goes offline for any
reason, heartbeat on the second tells it to take over.  And there are
lots of config settings to tweak heartbeat.

-- 
-matt

Ruslan Sivak napsal(a):
> We are building an exchange cluster with two front end Outlook Web 
> Access servers.  We would like to at least have some sort of failover, 
> and prefereably load balancing for them.
> 
> Russ
Russ,
take a look at http://httpd.apache.org/docs/2.2/mod/mod_proxy_balancer.html
David