Re: high availability?

From: Adam bultman <adamb@glaven.org>
Date: Mon Oct 18 2004 - 17:22:45 AKDT

Jeremy Austin wrote:

>Does anyone have any experience implementing Heartbeat or other
>high-availability services? I've got a few PII-233s with 2Gb HDs, and
>I'd like to make a few network services redundant.
>
>DHCP
>DNS
>routing (is this possible?)
>
>I know how to make squid redundant, and have a few ideas about DNS,
>but I don't have faintest clue of what to do about routing. I have
>four or five NATted subnets, and three upstream providers.
>Currently I have far too many single points of failure, and zero hot
>spares (I know, I know. I'm bad.)
>
>I've seen clustering stuff like openmosix and things like that, but
>I'm not trying to cluster processes (I think.) Just provide hot
>failover for the critical applications, which on my network are file
>serving, printing (needs DNS) and Internet access (with or without
>squid.)
>
>(I'd be happy to put my finds into the wiki, Mike.)
>
>
>
For routing, if you're going to use linux, look into VRRPd. I run it on
the routers at work (on our imagestream routers) and apart from VPNs
(which can't fail over, really) it works rather well. Kill one machine,
the other takes over. Kill the other when the other one comes up...
fine! Caveat: If you push a LOT of traffic, you might find your CPUs
busier than normal (I do, and mine are 900 MHz Celerons). You shouldn't
have too many problems; when we send bulk mail (remember, we have
clients that are nonprofits) we run into problems. Otherwise, we're fine.

For DNS, you'll just want to set up two machines, with one being master,
and the other being slave. Shouldn't be too big a deal. For other
services (SMTP, www, etc) you can try the Linux Virtual Server project,
also packaged up nicely in the UltraMonkey project. I use UltraMonkey
at work, and save a few... interesting tidbits, it works well. It
balances load very nicely over our four serverblades, and soon, I'll be
using it to balance imap,pop3,and smtp. (Unfortunately, UM doesn't work
for mysql, or I'd do that, too.)

You've got lots of choices, a little research and hard work and you'll
be there soon enough!

Adam

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Received on Mon Oct 18 17:22:30 2004

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