Hi, I work for a company that develops and hosts websites for several companies. We have 8 servers in our system, most of them dedicated to different purposes. some of them don't do much of anything. some of them are crucial. We have our main apache server, there's a development apache server, there's one that handles mysql and backups. And theirs our central server that handles sendmail and DNS. As you can tell this is critical. Everything pretty much goes through this server. What we want to do is take one of our 8 servers that is actually not doing anything at all right now and make it a redundant backup to the central server, so that if our central server goes down, we can still have mail and DNS working properly. We've had a couple instances over the last few months where something fishy happens and we have to reboot our central server, and we hate doing that. We try to only allow that to happen after hours, but our clients have clients all over the world, so there's not really an "off hours" time to do it. My question is. What do I need to do to get this set up? Obviously it's a bit of a bigger issue than just a simple forum discussion can address, but can someone point me in the right direction? Both servers in question run RHEL 5 Thanks.
I recently had this same conversation with the owner of a local hosting provider. There are a number of things you can do depending on your budget and available resources. Yes, this is a bigger issue than can be addressed on a forum and more detail would need to be provided. Right now you need to make a backup of your DNS zone records, then private message me for details. You would also benefit from trying to diagram your existing environment noting any dependencies. Making DNS and mail redundant is two separate issues, depending primarily on the type of software you are using. Fortunately to correct the situation won't cost as much as you might lose with a failure. Private message me with contact information if you would like to talk about this situation. Too many questions to address on this forum. Best, Justin
This is a standard procedure for almost any ISP Set up a slave dns server and a backup mx server on one of your other machines. You can add the backup mail server in the DNS MX record, and in the event that your main smtp server goes down, your backup mx will spool any incoming mail until your primary server goes back up. Setting up a slave DNS server is pretty painless too. Both procedures are well covered in the documentation.
@Hsh is right, assuming you have a Bind DNS server and your mail it adding another SMTP mail queue is all you need. However, if you are talking about redundant services on your end-users POP accounts, then you'll have the customer service issue of having mail unavailable during the move. Again, depending on the software you are using and the rate of your growth, how you would address the situation is different. Some POP systems will let you add additional nodes, while others don't handle that well. You sound like a growing firm and that you'll know what is best for the safety of your customers. How every you handle this, be sure you have regular backups before and after the change. You'll also want to work in your plan over phases to reduce any interruptions in service (i.e. handle DNS first, then test, then SMTP/POP, then test). Good luck. Best, Justin