[ale] failover planning

Greg Freemyer greg.freemyer at gmail.com
Mon Nov 29 19:42:47 EST 2004


On Mon, 29 Nov 2004 09:51:34 -0500, James P. Kinney III
<jkinney at localnetsolutions.com> wrote:
> I am looking at setting up a small non-local redundant webserver. The
> net access for each node is through different ISP's so each node has
> different IP's. In fact, there is nothing in common between the two
> different networks. They have no common router.
> 
> The main site is serverd by a T1 line that is susceptable to an outage
> caused by falling trees. I would like to make the outage as short as
> possible by making the backup site live as fast as possible. Right now,
> other than editing the DNS listing and waiting for the change to
> propogate, I have no other way to do this.
> 
> Any suggestions?
> --
> James P. Kinney III          \Changing the mobile computing world/

If nothing else, you could try round-robin DNS.

That way roughly half of your dns quiries will go to each IP.

Then set your client TTL low so your users are requesting a new DNS
entry fairly often.

If one of your sites fails,  there is a 50% chance your users will go
to the other site with their next DNS request.  (ie. if you have M$
users, they do a dns request at least once per reboot.)

Greg
-- 
Greg Freemyer



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