Opinions on network structure wanted...

Booty

Senior member
Aug 4, 2000
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Okay, so the owner of the company I work for is pretty hesitant to drop money, as most are. Currently, the company has about 25 employees - 15 or so in the main office, then 5 in each of the branch offices. There is a VPN connection to each of the outer branches. The company has one main application that they pretty much rely on - any downtime at all is pretty much a disaster.

Before I got here, they had 4 servers. The most powerful one was used as a primary domain controller running Windows (Server) 2000 - it also runs Exchange and has a DLT drive which is the primary means of backup around here. The other 3 were used for the application - one as the app server (2nd most powerful here), one to host the production database, and the last to host a demo database (the last 2 servers are basically identical, except there's a DDS tape drive in the production database server).

Since I've been here, they've added a basic webserver and, more recently, a new app server to host the newest version of the application they rely on. The new version no longer requires 3 servers - so they are now free to be used elsewhere.

Our original plan was to turn them all into secondary domain controllers and file servers - one in each branch office.

However, our contact at the software company who writes the application suggested having a backup server in place for the application server, which I fully agree with. However, I don't want to give up having secondary domain controllers in each office - I think that's pretty important. So we're possibly looking at getting another server to either backup the DC in the main office or to backup the app server, whichever makes the most sense.

Doing some browsing through forums and what not, though - I am pretty new to all this, after all - I'm seeing that we probably shouldn't be running Exchange on the primary DC - that it should, in fact, have its own server. Is this pretty much the popular opinion?

To complicate things further, there is a possibility that, if a certain account takes off like we expect it to, we may be adding up to 6 new offices around the country within the next 2 years(!). So, obviously, I want to be ready for that.

So, I guess I'm looking for expert (or at least educated) opinions on what all needs to be done with this network over the next couple years. I want to lay out a plan and work out a budget with the owner to get this thing where it needs to be, because I definitely feel like they've been lucky not have an outage in the last 3 years or so (when they've really started growing more rapidly).

If you have questions or need more information, I'll do my best to supply it - I've been somewhat vague, I know, but I don't want to give out any more information about the actual company than I have to, obviously.

Thanks so much in advance...
 

Kelemvor

Lifer
May 23, 2002
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I would definitely have Exchange on its own server. Other than that I can't say since I don't know much about PDCs. But having a backup of an app server that is the main app of the company would seem to be a pretty good idea as well.

If you don't have SDCs now, then I'd start with 1 server to Exchange, 1 to the Ap Backup. You can always add the SDCs now it won't hurt to still not have them for the time being... Then you can add them in at a later date.
 

Booty

Senior member
Aug 4, 2000
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Well, the thing with the SDC's is that if users can't authenticate, they can't access the app server even if it is up, so having at least one backup DC is pretty important... if you're saying it's not imperitive that we have them out at the branch offices yet, then I definitely agree with that, but that's the direction I'd like to go when it's all said and done.

What I need most is opinions on what all we should have in place, long-term. I'm putting together some system specs on the current servers, so that hopefully people on here can give me a better idea of how long I can expect them to last in whatever roles they are used in.
 

netsysadmin

Senior member
Feb 17, 2002
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Just setup one extra DC at the main office as backup. I doubt you see enough authentication traffic across your VPN to place a DC at the remote office. Also keep in mind that you will also add replication traffic to your VPN if you place DC's at your remote offices.

I would definately have exchange on it own machine since it is exposed to the internet. Also make sure the machine has a RAID setup and a good backup scheme. Because when email goes down life always manages to stop when it comes to the management. You can loose you database apps and you would be OK, but it always seems when email goes down someone always gets fired.

PS...DO you have a firewall setp? Maybe you should be spending money on one if you dont.

John
 

Booty

Senior member
Aug 4, 2000
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John - Actually, the database apps are much more essential to this particular company than e-mail, but either way I do want Exchange on its own box. Yes, we have VPN firewalls installed in all offices - nothing insanely expensive, but not cheap-o units either.

I thought I'd go ahead and update this thread with specs on our current servers:

Server Role : Specs
PDC/Exchange : 2x1.8 GHz Xeons, 1 GB ram, 3x36 GB RAID 5, DLT tape unit
App Server: 2x3.0 GHz Xeons, 3 GB ram, 2x36 GB RAID 1 (OS), 3x36 GB RAID 5 (data), dat72 tape unit
Web Server: 2.4 GHz Xeons, 512 MB ram, 2x36 GB RAID 1
Old App/DB Servers (the new app server replaces all 3 of these):
(App) 2.0 GHz Xeon, 1 GB ram, 2x73 GB RAID 1
(Production) 2x700 MHz Xeons, 1 GB ram, 2x25 GB RAID 1, dds tape unit
(Test/Demo) 700 MHz Xeons, 1 GB ram, 18 GB HDD

So that's a brief rundown of what we have... most of this was setup before I got here. I'm now trying to find the best use for what we have, and to acquire the appropriate equipment to get where we should be.
 

err

Platinum Member
Oct 11, 1999
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I guess if you really have no choice, running exchange on the DC is fine. I have that setup for almost 4 years now without any problem.

However I would definitely suggest an additional DC for disaster recovery and redundancy purposes. There is no excuse in running your whole infrastructure only one 1 DC. It is way too risky. If you lose the DC, thats it... bye bye, sayonara... good luck with recovering authentication server, dns, and not to mention the possibility of having to reconfigure ALL of your workstations.

If budget still won't permit you to have another box, I would at least recommend VMWare or VirtualPC alternative to run your secondary DC. Yes this is not the best, but it is definitely better than nothing.

You have stome strong servers there and it would never hurt to configure your second DC using a workstation class machine, rather than nothing. I cannot emphasize about the importance of having second DC.

 

d3n

Golden Member
Mar 13, 2004
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Sounds good to me so far. My only suggestion is that you have a test server for your central app. You need to have a comprehensive backuplan with onsite and offsite storage. Full backups and incremental. And TEST them on a test server. I?ve seen it happen too many times that the backup was fubar'd.
 

Booty

Senior member
Aug 4, 2000
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Okay, here's what we're looking at now...

We're going to upgrade the memory on the old app server so that it can be a backup of the new app server. The two other old server will be made into domain controllers of some sort - either to stay at the main office or to go to branch offices. We haven't decided yet.

Here's the main thing, though - we're going to go ahead and get another new server so that we can seperate Exchange from the primary DC. We're thinking that the new server we order should become the PDC - then leave the exchange machine how it is (and possibly leave it as a secondary DC? not sure if that's a good idea or not). So this new server probably doesn't have to be extremely expensive since it's only going to handle authentication, right? Maybe something similar to the web server?

 

dphantom

Diamond Member
Jan 14, 2005
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Just so everyone is saying same thing, since W2k, no longer PDC or backup DC. Does have a PDC Emulator mode for mixed NT/W2K domains.

"PDC Emulator. Mixed Mode; Acts as NT PDC to NT BDCs"

That being said, I'd pretty much agree with your path. I like Exchange on its own server, but money is always an issue. I had to run Exchange 5.5 on my DC for 2+ years before I could get money to move it off.

If your DC is going to do nothing but be a DC and run services like DNS/DHCP/NTP, then a lower powered server than what you would need for an Exchange box is appropriate.

 

dphantom

Diamond Member
Jan 14, 2005
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Originally posted by: dphantom
Just so everyone is saying same thing, since W2k, no longer PDC or backup DC. Does have a PDC Emulator mode for mixed NT/W2K domains.

"PDC Emulator. Mixed Mode; Acts as NT PDC to NT BDCs"

That being said, I'd pretty much agree with your path. I like Exchange on its own server, but money is always an issue. I had to run Exchange 5.5 on my DC for 2+ years before I could get money to move it off.

If your DC is going to do nothing but be a DC and run services like DNS/DHCP/NTP, then a lower powered server than what you would need for an Exchange box is appropriate.


EDIT update

2000 client PCs and member servers synchronize with authenticating DC
If unavailable then with another DC in the same domain
Other DCs in a domain synchronize with domain PDC emulator
PDC emulator synchronizes with PDC emulator in another domain using domain hierarchy to determine which to synchronize with
Ultimately PDC emulators synchronize with forest root PDC emulator
Forest root PDC emulator can be configured to synchronize with external time source (ntp)

:Q