Problems with NLB

I've tried to NLB using two Virtual Server 2003 SBS Servers. I know you shouldn't really do it on domain controllers but it's only for test purposes so should work ok right? Do I have to set multicast on each Server under the NLB tab or does it need to stay on unicast? It says something about not being able to connect to all nodes if unicast is on when you load NLB manager up. It keeps going to converged then pending and now it's on miconfigured lol. Any ideas as to why it's not working?
Comments
http://technet.microsoft.com/en-us/library/cc775749.aspx
Unicast overwrites the MAC. So because of that, you need 2 NICs when using Unicast. The NICs dedicated to Unicast will be used for incoming traffic. These NICs should be on their own Vlan, Switch, or a hub off of a switch so it doesn't turn your switch into a hub. This is because the two NICs will have the same MAC and because of that, the switch will end up sending data to every port on the switch turning it into a hub.
For multicast, it doesn't re-write the MACs, it essentially adds the MAC to the existing NICs. Because of this, you can use 1 NIC. But your switch needs to be able to configure static ARP entries so the switch knows which server is which. If your switch supports IGMP, you can enable Multicast IGMP which your switch as well as your NICs need to support. I believe IGMP will automatically prevent switch port flooding.
Personally, I would just use two NICs and Unicast Mode.
Thanks for getting straight to the point "I would just use two NICs and Unicast Mode" That's the kind of information you can't find when searching through google and having to read the pages and pages of explanation and theory lol. I'll create another virtual NIC on my Virtual PC Server for both Servers and test again tomorrow. Should work a treat with both Domain Controllers using Unicast with 2 NICs each shouldn't it?
Does there have to be any specific ranges of IP Addresses on each Servers NIC like Clustering where each IP range and subnet has to be different?
Also, with NLB, am I right in thinking that as it is not as safe as Clustering (i.e. one Server goes down, the other nodes can reach the central storage to continue access) with NLB, if the main Server goes down that you set up the NLB on, does that screw everything up, or does NLB put some sort of DNS record on the Server that somehow re-directs clients to the alternative 'Web Servers' if you like?
(Another quick q
Diagrams really help me to understand and visualise things as I haven't covered this stuff before.
Typically in NLB farms you don't have a shared storage device. For example, in a typical IIS scenario you'd have IIS running on each server, configured the same, and you would load-balance the required ports but you would have identical copies of the data/web application files on each node. You can use any number of methods for keeping each server in sync whether its a manual process or using DFS, robocopy, xcopy etc. Of course, you can configure IIS to use shares to link to a central location but I've not seen it that often. Think of NLB as a means of distributing connections (load) between multiple devices rather than it using shared storage - it doesn't require it whereas clustering does.
Data that changes frequently is often stored in a database, and of course you'd use clustering as a high availability technique for that
Hope I've explained this OK, I've just re-read it and it's as clear as mud to me though I'm v.tired
If you can take the website offline for a minute, let robocopy do its thing once, then set it to run every 15 minutes will that work for you? How often is the website updated? Otherwise yes, ntbackup should work, but unless the site is updated almost constantly why would it need to run every 15 minutes vs once per night or something?
You could use schtasks to run an ntbackup batch file every 15 minutes something like this:
However, even at that ntbackup wants you to create a "bkf" file, not just a direct copy like you would get with robocopy or something.
Instead of having to screw around with scheduling, why don't you just create a script and run as needed?
http://www.eggheadcafe.com/tutorials/aspnet/f6972828-1e81-4cd4-ae0c-36196a82ed25/workstation-open-file-bac.aspx
I suppose syncing the website isn't required every 15mins, I was just using that as an example as I didn't think about open files been a problem to be fair. The site will remain static mostly so just once a night would be fine. It sounds like robocopy would suit my requirements fine then.
If Robocopy sees that files are open, will it simply skip those files until it's next backup when it will retry and then copy them if they are inactive? Can Robocopy run as schedules? If so, do you need to set up a batch file and a scheduled task, or is there a more preferred method?
I'm not sure I understand what you mean here dynamik. Isn't a file open the same as a file in use?
Although that looks very clever, after such a hard day as the office that was far too much scripting to get my head around
I see, sorry, I didn't read it properly. I've been so busy today that my posts I have checked on I have more glanced over.
Now that I have mastered the multicast way of setting up NLB, I was looking into going down the unicast route as I have heard that it is a good idea to split NLB traffic from your public facing traffic.
I have 2 servers here with 2 NICs each set up as follows..
Server1.testdomain.local Server2.testdomain.local
Private = 10.0.0.1, 255.0.0.0 Private = 10.0.0.2, 255.0.0.0
Public = 192.168.1.1, 255.255.255.0 Public = 192.168.1.2, 255.255.255.0
I have set it up this way as i've read that having your public traffic on a seperate subnet is good practise?
Now i'm trying to look for a very thorough guide as to how to set up unicast NLB, but all I can find are vague answers and no detailed guides with pictures and clear explanations of not just where stuff goes, but also why. If anyone has a link kicking around or has some spare time to do this, it would be great.