HA on a budget (Full Version)

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koolgeek -> HA on a budget (2.Mar.2011 4:25:15 PM)

The answer to this seems too obvious to ask and I risk looking silly for asking it, but I've been pondering it for a couple of days now.

I have one fully functioning and in production 2010 Exchange server, with CAS, HT, and MB roles (no ET). Incoming Email is forwarded to HT via a Sendio spam box. Outgoing email is configured correctly and functioning. All is well.

I now have been instructed to implement a poor mans HA solution, so I want to add a 2nd 2010 server but my boss doesn't want to go with a Hardware Load Balancer. So the idea is to create a 2 server DAG with appropriate FSW. The exact same roles will be installed on the backup server. Of course, this will require manual edits of DNS, firewall entries etc. during a failover...understood.

In the event of a server meltdown, the requirement is for the 2nd server to be able to take over within a reasonable amount of time. The DAG will have taken care of the database and logs being replicated over...also understood.

I "get it" fully until the point of installing the 2nd 2010 server. To wit...do I install this server as an Internet facing server, and do I create a send connector (* addresses) exactly like I have done on the 1st server? Won't this create a second OWA web site and does this create some direct Exchange to Exchange identity problems? On the face of it, this seems okay, though it is a stovepiping of each Exchange server.

Anyone know of a resource that step-by-step spells out all parts of configuring said redundant Exchange setup (even down to duplicating the SAN certificate onto the new server). Again, when the first Exchange goes down, this backup Exchange has to be able to assume ALL email related duties (external (OWA), and internal.

I thank you kindly for your assistance.

de.blackman -> RE: HA on a budget (3.Mar.2011 8:27:45 AM)


Unfortunately I do not beleive you will ever find any "step by step guides" for exchange for the simple reason that every exchange organization is tailored to the company deploying it.

Now for your "poor man's HA", what you are doing will work fine but I will be very honest when I say you will have to make sure that you document EVERYTHING that needs to be done in the case of a failover!! I would try and script the failovers with the DNS IP changes and everything else! (this is where you will need a virtualized lab to test things out!)

Have you thought of maybe changing your design a little bit. If this was my environment, I would setup 3 new servers,2 running the CAS and hub transport roles and use windows NLB to load balance the 2 roles; the 3rd server would be the 2nd mailbox role and finally i would remove the CAS and hub roles from the original server. This will give you HA for all roles!

koolgeek -> RE: HA on a budget (3.Mar.2011 11:15:33 AM)

Thanks for your reply. Unfortunately, my boss has me on a tight budget, otherwise, I would have definitely gone for the 4 server solution (Microsoft has this as one of their recommended setups). I've got to make do with only 2 servers.

I guess that's why I was also hoping to get an answer to the 2nd part of my question. When I'm standing up the 2nd server, do I install it using all of the same settings as the first (I set it up as an Internet facing server, and I create a Send connector etc? My gut tells me it HAS to be this way.

I very much appreciate your time.

de.blackman -> RE: HA on a budget (3.Mar.2011 11:23:53 AM)

Well since it seems you are on a budget, there really is no option but I still recommend you tell your management the recommended path to take (may be more expensive now) but allows for easier transition and provides all that you are looking for, properly deployed [:D]!

Yes you will have to configure it identically as the first server. Don't forget to copey the certificate over as well and configure the same URLs on both servers. Basically any custom setting you made on the server (server configuration of the EMC) needs to be duplicated on new server. Organization Configuration settings (such as send connectors) do not need to be duplicated. You can simply add the new server as a source in the existing send connector.

koolgeek -> RE: HA on a budget (3.Mar.2011 11:49:27 AM)

Your answers have been most helpful. I'm guessing that if the primary server fails, the secondary server's configuration as a source server in the Send connector (which has been replicated over) will automatically take over sending duties once the DB has been mounted.

In the end, I think a Hardware load balancer (HLB) or even a Virtual Load Balancer is the cheapest way, and much more reliable/quicker than the "other" HLB (Human Load Balancer). ;-) I've heard some good things about Kemps line of HLB's.

de.blackman -> RE: HA on a budget (3.Mar.2011 12:36:14 PM)

Actually since both servers are listed on the send connector as source servers, both will be allowed to send out. If you would prefer to leave the second server strictly as a standby then you will have to create a second send connector and change the cost to something low than the first one. That way if first server using first connector is not available, the next higher cost will be used. And I definitely agree that hardware load balancers are the best for providing high availability!

koolgeek -> RE: HA on a budget (3.Mar.2011 1:10:00 PM)

Perfect...and a good solution! I'm worried (perhaps incorrectly) that leaving the 2nd server as a co-equal source server will lead to some emails being indavertently routed to it, and failing to be delivered externally. No mailboxes will reside on it (at least not until a failover).

Maybe this would be a good thing as it would take over sending duties if the primary hub transport role experiences problems? But then this would also be resolved by creating a 2nd send connector with a lower cost, so I think that is the route I'll take.

I'm assuming internal email sending needs no mods at all since there is a send connector that was automatically created during installation and that only allowed sending between Exchange users. HT's speak natively to each other.

Many thanks again. It's really been helpful.

de.blackman -> RE: HA on a budget (3.Mar.2011 1:20:16 PM)

You got it[:D]! But i think I may have said something wrong! The second connector you create should have a higher cost if you do not want it being the primary. higher cost means lower priority - lower cost means higher priority!

Good luck with it all!

koolgeek -> RE: HA on a budget (3.Mar.2011 1:30:36 PM)

Sorry...you're right. Thank you kindly for all of your words of wisdom.

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