Redundant MS Exchange Servers

[tfleming]

We're trying to set up an Exchange 2003 environment in such a way that mail services are never down. We're thinking 2 Exchange Servers under the one domain might be the simplest way to go. One of them would be the primary Exchange server with the MX1 record pointing to it and the other a 'secondary' Exchange server with an MX2 record pointing to it.

If the primary server goes down, then Outlook would have to be changed to point to the secondary server and there probably would be no access to old mail messages, but pop2 and smpt would still function for the time period it takes to get the primary mail server up. This would be good enough. The key point is that there would be close to no down time for incoming and outgoing mail.

Does this make sense? Anyone have another suggestion? I know Exchange Enterprise is another option, but this is only to server as a backup for incoming/outgoing in the event the primary mail server is down.

 

[halfadder]

Sounds like a good enough solution.

Exchange Enterprise is a very common setup. Almost every time I've seen an Exchange installation it usualy involves a full rack of Dell servers: many redundant exchange servers, at least one RAID and fileserver, and at least a pair of directory servers. Even for small companies / small installations Maybe Dell and Microsoft have some sort of a special price for a full rack installation?

 

[spyordie007]

You've got a couple of options.

1. If you just want to ensure that your organization can always recieve mail you could setup another server with SMTP (no need for an exchange license) and give it a higher MX preference in your external DNS server(s) so that it would recieve incoming mail and hold it in the event that your exchange server is unavailable. However if the Exchange server is down than your users will not be able to access their mailboxes or send mail.

2. The only way that you would be able to address the ability for them to have mailbox access in the absense of a particular server would be to setup a server cluster. However I'm going to guess that if these are the questions you're asking at this point than you are a long way away from needing a server cluster.

I think you may want to look into option #1; you wont be able to access your mailbox or send email. However you would still recieve email from the outside world in the event that your exchange server goes down.

 

[dphantom]

Welcome to the forum.

Your solution would work, but would require users changing settings any time your primary Exchange box went down. I'd prefer the cluster environment using Exchange Enterprise. I think you'd find the managment easier and less frustration on your end-users who would not need to change their Outlook setings.

My setup is a pair of HP DL360s tied to our SAN. The SAN already existed so adding the HBAs to the servers was easy and now if one of the servers goes down for any reason, the other picks up very quickly.

 

[tfleming]

This is a small Exchange environment with only 20 users, but mail is absolutely critical, so I'd like to avoid the expense of Enterprise -- thats why I'm looking at this simple mail service. As long as they can send and receive mail if the primary Exchange server is down - even without access to previous mail messages - then they'd be happy.

Any other issues with the 2 Exchange server setup?

 

[classy]

You should put the two in a cluster. Unfortunately only the more expensive Enterprise supports a cluster enviroment. To be honest for only 20 users, I would setup a nice Exchange server and rather spend money a second copy of exchange I would use a RAID 5 array on one server. If you use only the server for Exchange you shouldn't have any problems. You could also solve your problem by using two Exchange servers in NLB, which is supported even on the Standard edition of server 2003. That would probably be your best bet. Oh NLB stands for Network Load Balancing.

 

[spyordie007]

For 20 users it would be way over the top to even spend the money for 2 exchange standard plus 2 windows standard licenses.

I think using NLB to cluster Exchange services is a bad idea because NLB is not service aware. Besides if the primary server were to go down users wouldnt have access to their data (which is the whole point of clustering, to have your services up regardless of if a server goes down). It's also going to add considerable complexity to your setup, in an operation as small as yours keeping things simple is very important.

I recomend you do a combination of a couple of things:
1. See classy's suggestion about building a good server. Buy a good server using redundant hardware (powersupplies, hardware RAID, etc.) and have good service on it. This is the most important thing you should be doing, spend 95+% of your time, money and efforts here.
2. Setup the standard SMTP engine on another server (not exchange so you dont have to buy another license of it) and set it as a higher cost in the mx record. This way if your exchange server is down you can still accept mail from the outside (the SMTP service would just hold it until the exchange server came back online).

Good Luck,

-Erik

 

[Daniel]

I have external DNS services through easydns.com. They have the ability to queue up your mail if your mail server goes down for up to 7 days. I realize you want to be able to send as well but it's a nice option if your regular mailserver goes down for whatever reason at least you don't lose your incoming messages.