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multihoming server in 2 subnet network

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by bshaw400

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I have a Win2k3 server running in a small lan right now. However, it hosts a very noisy but critical app that the users (~20) depend on. The server is an HP ML150G2 with 1Gb nic and the users have current HP workstations with 10/100 nics. Server is setup as ADS, DNS.

When everyone is using this app, the network performance hits 100% in performance monitor counters and the app starts dropping or getting hung at the client stations. When there are 5-10 users on, everything runs ok even though the network performance occasionally hits 100%. It's when we exceed that number of users (using the app) that we start having app failures.

There is a small Dlink DSL router-10/100 Mb switch unit connected to a 24 port DLink 10/100Mb managed switch; these are on a 192.168.0.x subnet. Everyone has access to the Internet through the DLink router (NATting)although not everyone is allowed through.

I think the problem (other than this noisy app which I can't get rid of) is that the 1Gb connection on the server is maxed out; I had mounted a 2nd 1Gb nic on the machine when I built as a just in case card so I would like to try and use it.

What I would like to do is put half of the users on the 2nd nic with a spare 1Gb switch I have available. The 2nd nic and it's "users" would be on a different subnet (ie. 192.168.1.x); I'm even ok with putting this group on fixed IPs as they happen to be more critical users. However, I'm not sure how I would get the router to "see" and route the 2nd subnet correctly.

BTW, all users still have to be able to get Web access. My thinking is that putting a fixed IP on the 2nd server nic (ie, 192.168.1.10) and putting fixed IPs on 10 of the workstations (192.168.1.100-110) normally would not be a big deal. However, the routing part is a problem for me since there is a single gateway (192.168.0.1 on the router). If I connect the 2nd switch with 2nd IP subnet users to the router, would the router recognize it correctly? Would using a net mask of 255.255.0.0 allow this to run correctly? Anyone have any advice?

13 replies

by cg it

or cluster it with another server.

your problem isn't infrastructure, its the server isn't hefty enough.

The ML 150 supports up to 8GB of memory and your running only 1 GB. A typical amount for a desktop but not a server. Expecially not with 20 users that must use that application.

Next question, is this a terminal server app or is this an app on desktops that access a share on the server or a DB on another server?

by bshaw400

1. - Server has 5 GB of memory and a 1 Gb integrated nic.

2. - App is a crappy/cranky "client/server" app that has a workstation "medium" client and a server based server app. I can't get rid of it because it runs the businesses financials (looking for something better still). It is the real culprit as it is a hybrid DOS/.Net application that is a piece of junk. But I have no control over getting rid of it (yet).

It uses a share on the server and has its' own "DB"; quotation marks are mine because the outfit that owns it created it. My preference would be to use a real DB even if it came from MS or MySQL. At least with those, I can gen/tweak my own code relatively easily.

by bshaw400

BTW, when ALL users are logged onto domain, there are no problems. I created a simple batch file that run 25 ping sessions per machine with 65k buffers per ping session continuously until I manually shut down the session. The network performance is fine during this period and I can go to network drives and shares without any delay and pull down files and open files fine. It's just when the app is started up and 10+ app users get on that the app starts hanging up.

by cg it

it's the application that causing the problem. The only solution would be from the makers of the application.

nothing you do infrastructure wise will help performance if A. The server running the application has enough resources to handle the load and you still have performance problems. B The application designers didn't create the program for support of 20+ users [Terminal Services]. You mentioned this is a legacy program [assuming 16 bit]. that in itself is a performance problem.

by bshaw400

I don't really have much choice to change the app yet. My original intent is to satisfy the customers need enough so he can still work. I can point all day to the app and argue with the app vendor but in the end I am still stuck with the customers need to do "something" so I basically have to go extreme lengths to prove that there is nothing else to do.

So my question really revolves around how to multi home the server and get the network to run correctly EVEN THOUGH THE NETWORK IS OK. So we have to treat the issue as really a non-app problem. This is more of a technical exercise then. The requirement set by me really should have been : I need to get a multihomed Win2k3 server/20 Win XP client setup with a 2 subnet network running correctly with the previously mentioned IP subnets.

Forget the problem app; my mistake was even mentioning it. This is a technical exercise for a network problem. Any advice?

by cg it

let the switch do the work not the server.

by triathlete1981

you sound like you're getting a little heated pal. calm down.

we're running pfs (professional file system) as an instruction program to give work orders to floor supervisors. unfortunately, it's DOS based. DOS blows. it's 2007. let's move on. but you can't.

i don't really think adding a second nic is going to improve anything. everyone's still going to be accessing the same app. if one 1gb nic can't handle a measly 20 users, than adding a second one is just going to waste your money.

and 5gb is plenty for that amount of people. just out of curiosity, what kind of application is it? those with the Yes/No decision about when to spend money sometimes don't like IT people because we are the ones who usually say,"what you want done can't be done unless you spend some money."

i think it may be time to start the process of transitioning to a newer program. if it's DOS-based, there's your problem. any DOS-based app can't handle what we need nowadays.

by triathlete1981

want to create a second subnet. you already said that running a continuous flow of pings to the server doesn't bog down the server. unless these ~20 users are each doing 50mbps of traffic to your 1gb nic at every second, than the connection is not to blame. which does make it an app problem.

20 users, even 50 users, is too small to subnet. my network is 100 users, and we're all using one subnet. my nic is 1gb also with 2gb of ram. yes, i know. i need more ram. but there is no one app that brings down the network, even the retarded DOS pfs program.

in the end, what you're most likely going to realize is that you need to migrate to a different financial program, like AS400 or similar.

by bshaw400

Ha, I come out of AS400/iSeries so I know of what you speak of. And yes, that would be the perfect setup which is what I am slowly working toward. However, there is not much in the way of Medical Office management/billing software that runs on small iSeries. Most of it, naturally, is designed for hospitals or giant groups (a la Kaiser Permanente). So until I find a decent iSeries based tool, I'm stuck. What I would love to see is a tool I can run on the new 515/525 Express machines but alas they do not exist yet.

In any event, they want to see me trying something so.....here we are.

by bshaw400

I apologize to all if I sounded as if I were getting bent; I wasn't, just throwing the reply out there quick while doing other things.

I already have the ball rolling on the powers-that-be thinking of replacing the app which is a medical office app. So we are at least thinking about it. But my experience in these dramatic transition/upgrades out of custom software is that it can often take a long time (6 months - 1 year is good) much less be entirely successful. So I have to temper expectations somewhat.

In any event, I do share all the angst about DOS already. However, we really don't have any choice right now; the billing system HAS to run better. Doesn't have to be perfect, just better. So, to satisfy them I have to do some hardware fiddling.

by triathlete1981

the only thing i can think is that, and this would be dependent on whether or not the software can do this...

you said access to the app causes no problems if there are 5-10 users, only when more are connected. can you work offline with excess users? this is a software feature in some apps; i don't know if with yours. contact the software vendor again to see if this is possible.

if enough people use this, you must already have a copy of the program files on the ~20 users' computers. this is how the pfs system works in my network. when files are brought up, yes they retrieve data from the server, but the connection to the server is immediately terminated after lookup and the data is cached locally. when a change is made to a file in pfs, the connection is recreated to the server and the pfs database is updated. it's not quite the same as working offline, but very similar.

you need to contact whoever made the software and not tell them there's a problem but see if there's a way to work offline.

you're already familiar with the as400, and you know that if people don't close their session properly, the as400 still thinks that user's session is current. are your users closing sessions gracefully?

if these things don't work, i don't know.

by bshaw400

Yes, I think I might try that as an interim solution. So I have to figure how that will run on these switches (1 Layer2, 1 Layer3).

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