Here's a page discussing clustering two linux/apache servers:

http://www.linuxfocus.org/English/November2000/article179.shtml

This could be adapted to NT without too much fuss I'm sure.  

Other options are mostly commercial from what I've seen.  I've worked with
Legato's Cluster, and Mission Critical Linux has been getting some press
recently.  A search on google should give you quite a bit to choose from.

Blake Barnett
Sr. Unix Administrator for DevelopOnline.com
480.377.6816 T 480.736.9211 F
blake.barnett@developonline.com


-----Original Message-----
From: Mark Peoples [mailto:gascsd@gascairlines.com]
Sent: Saturday, November 04, 2000 8:12 PM
To: plug-discuss@lists.PLUG.phoenix.az.us
Subject: RE: Linux as backup (failover) machine


Got access to modify your DNS?

On the primary nameserver for the domain(s), try connecting to your
webserver. If no connection, change the DNS to point to your Linux box via a
shell script. On the slave nameserver, just don't keep a local copy of the
domain record(s).

To be more careful and to prevent 'accidental' network hiccoughups, this is
what i'd say to my boss:

1. shell script that pings webserver
2. if ping doesn't respond, open a connection on port 80 of your webserver
3. if connection fails, run a script to alter DNS (change ip of your
webserver)

ICMP. If this doesn't work, it may not be there after all, but try TCP/IP
just to be absolutely sure it's not there. If TCP/IP isn't working, then
changeover to the linux box.

Problem is, you'll need to change the caching times for your domain(s)
unless you don't mind longer expiration times. But, this would be extra work
for your nameserver(s).  =(

No hardware and no extra software. =)

marco

-----Original Message-----
From: plug-discuss-admin@lists.PLUG.phoenix.az.us
[mailto:plug-discuss-admin@lists.PLUG.phoenix.az.us]On Behalf Of Ken
Bowley
Sent: Friday, November 03, 2000 6:12 PM
To: PLUG Discuss
Subject: Linux as backup (failover) machine


Hello everyone!

I've been posed with a question, and I'm a little stumped... please bear
with me.

Problem:
Make a Linux machine automatically kick in as a failover machine for http
when the NT machine goes down.

Restrictions:
Need to be able to monitor the NT box without installing anything extra on
the NT machine.
Linux machine needs to be able to kick in automatically when the NT box goes
down, and give control back to the NT box when it comes back up.
No access to installing any type of router/proxy between the NT and Linux
box and the rest of the net.

Please send your ideas either directly to myself, or to the list if this
problem is of interest to others.

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= O-
Ken Bowley/SysAdmin            mailto:johann@vikingsystems.com
Viking Systems, Inc.              http://www.vikingsystems.com
-=-=-=-=-=[Sair Linux and GNU Certified Professional]=-=-=-=-=-


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