Sweet.

I thought I'd summarize for archival purposes:

   1. Some browsers will attempt to use a secondary IP in a multi-IP A
   record, this will help with failover, but does not always work.
   2. DNS caching, some proxies and older/mobile browsers will only use the
   first IP it receives so if a server goes down and they receive the failed IP
   they will get an error. However this should be for a very short time.
   3. It is best to have at least two load balancers in your farm, so that
   the load is distributed and if one goes down there is at least one other to
   take the load.
   4. It is good to have the load balancers be in at least two AWS data
   centers to have HA over networks as well as EC2 instances.
   5. If a new instance comes up to take over the elastic-ip of a failed
   load balancer it will take from 30 seconds to a few minutes for this ip to
   take hold of the new instance. It has been my experience that this reliably
   happens in under a minute.
   6. IP take over of the elastic-ip will almost always be faster than
   updating DNS A record with a new IP.
   7. The above four items make for a pretty reliable/resonsive failover
   solution for the load balancers... not perfect, but pretty good.

Thanks for all your responses to this thread.


-- kevin


On Tue, Dec 16, 2008 at 10:22 AM, Alex Kovalyov <[email protected]>wrote:

>
>
>
>
> On 16.12.08 17:58, "Kevin Baker" <[email protected]> wrote:
>
> > Cool. Does HA Proxy do the IP take over? I was going to look into that.
>
>  HA Proxy is HAProxy from haproxy.1wt.eu. It does what nginx role does on
> Scalr, minus being able to serve static content directly from load
> balancing
> instances.
>
>
>
> >
>

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