On Tue, April 19, 2005 8:58 am, David McDowell said: > One in the same? Here's my idea. I'd like to use CentOS 4 if > possible to do this. I would like to have my webserver mirrored on > another machine so that if one goes down, the site continues to run. > If I change a config on one machine, the config should change on the > mirrored machine. Is this running a cluster or is this some other > kind of setup? Basically I have some time at work to play. Any good > resources for this kind of information? Basically I want 2 servers to > be identical mirrors of one another so that if one of the 2 goes down, > I'm still online. And, if I repair the broken one, it can resync > itself so that the mirror of the 2 machines is identical again. > Suggestions, links, etc? > > thanks, > David McD
First off unless I am mis-understanding clustering, it is not what you want. To me clustering is taking a group of machines and grouping them together so the can take advantage of a piece of software that knows how to disperse the processing load across each of the cluster members. I think mirrored servers are more what your looking for. So what about this, you have 1 web server that you consider the primary web server. You make all changes to Server A and rysnc all changes to server B. You then set both servers to have same names in DNS so DNS can do a simple round robin load balancing for you. Now when server A goes down, all you have to do is figure out how to manage the down box/dns. Some of that depends on how down server A is. How much of this that becomes automated depends on your script fu, and how critical web services are. For me I don't think I would need to automate more than the web data. This of course assumes that your web data is fairly static, other wise both web servers would have to point to a central DB, which then becomes the single point of failure unless you do failover for that as well. If your not running Nagios. I would heavily suggest you look into it. It's one of the best tools on my network. I have it monitor all servers and critial services and sends a email to my phone if things go down. I still have to implement a failover for nagios not being able to send the email due to the t-1 being down. But that has been a scenario I have had to face yet :). In any case most of the time nagios tells me of the failure before people do and I can work on restoring service. Note: I wrote this real quick, their are some obvious holes! And you need to evaluate what the specific needs are to determine how intricate your setup would need to be. I throw these simple suggestions out just to get everyone's creative thoughts flowing. Matt -- TriLUG mailing list : http://www.trilug.org/mailman/listinfo/trilug TriLUG Organizational FAQ : http://trilug.org/faq/ TriLUG Member Services FAQ : http://members.trilug.org/services_faq/ TriLUG PGP Keyring : http://trilug.org/~chrish/trilug.asc
