We have a server virtualisation project over the summer and as part of the process we are looking at restructuring our current infrastructure and server roles. At present we have a fairly standard RM implemented structure of 3 DC's, 2 of which run DNS, two of which host printers and all three of which are file servers for various shared areas/user profiles and work.
At present I am considering the following:
- Having 2 dedicated DC's which handle DHCP/DNS/AD etc. and absolutely nothing else.
- Having a further two virtual file servers which we will logically spread user/staff resources across (most likely staff and adult learning/student divide).
- Having a separate print server which will host ALL printers for the school.
The above to me seems to simplify the infrastructure slightly, giving virtual servers distinct roles and should help us pinpoint issues quickly should we have problems down the line. It should (in my mind) also prevent programs conflicting with each other and causing issues. My only worry is this is overkill and adding unnecessary server OS overhead although the servers we are getting will easily be able to handle this.
Can anyone see an issue with the plan above??? Is hosting all printers on one server a bit risky or is it fairly standard? My understanding (having thus far not used VMWare) is should a server fail a replacement will be back up and working with negligible downtime.
Cheers for any advice and pointers in advance,
in an ideal world I think we would all like to separate the server roles onto individual server instances but only a few will be in the lucky position to do so.
I personally think having all the print queues on one server which is dedicated for this task alone is a good route to go down.
With regards to this virtual infrastructure, what are you doing about storage? Are you implementing a SAN?
We did a similar thing last year. Moving to Virtualisation, away from CC3 and up to 2008R2 and W7 so was the perfect opportunity. From memory (not there anymore) we ended up with:
- 2 Domain services servers (one master and a secondary)
- 3 File servers (staff/student/shared)
- Print server
- DB server (for SIMS)
- IIS web server
- Apache web server
- Apps server
- AV server
& one other that I can't remember what it was. As you have said we tried to make a server per role, rather than jam anything on any server when we had physical servers, to allow us to reboot a problem server with a minimum of services disrupted. The only thing I never got fully to the bottom of was the recommendation that you don't run DHCP on a DC. I think in the end I put it on the print server just in case.
Beyond that, as long as you have enough capacity across all your physical servers (& the correct bits of VMware) so that if one goes down the others can take the strain then yes you can get a replacement up and running and no one will be the wiser except for maybe a bit of sluggishness.
Are you just having the one server or are you looking at a couple with shared storage.
The thing I find about Virtuals is you generally end up creating more as it is so easy, create a template file for instance and you can deploy a basic server up and running in half an 20 mins other enough resources being availble, being wary of under licensed is the only issue :spider:
We are a new build and virtualised almost everything. I think that your first instinct is right and with virtualisation tech the way it is now would very much go along the "one server one job" route.
Just one thought though, we have two virtual DC's but we also have physical DC located in another part of the building with a switched off DHCP scope set up- it doesn't need to be anything fancy (for a long time ours was an old Atom based work station) but it gives you an extra level of protection inre-building your network or jusry rigging something if your lose your physical hosts or have some issue with your VM storage.
Go virtual and split the print servers between office staff and classrooms, gives you a bit more leeway should something go wonky on one of them as only 50% of the servce will lose printing. Once you're on VM there's no need to shoehorn services onto one machine so keep them as split apart as you want to, makes life easier in the long run provided you're on EES licensing (use Windows Datacenter licensing for your VM host then you get unlimited guest licenses :) )
cheers for all the replies, all very useful and definitely think we will go down the "One Server... One Job" route. Just a big shift from what I am used to and the way things have been done in the past.
Our school is going to be a three node setup with shared storage.
With regards licensing (which is the one thing I thought about after posting this) we are currently on EES, but only for desktops. Can I be nosey and ask roughly what people are paying for Windows licensing and whether they think the Datacentre is a better buy than just buying perpetual licences? Has anyone looked at non-windows servers for things like File Servers? If so, what OS and can you recommend it?
EES with Datacenter for your VM hosts is the way to go, cost is a couple hundred £££ at most per license (it's done per physical CPU per host iirc) which will save you a lot in the long run if you're going down the separate VM route.
I'd also build some System Centre licensing into the project, again it's relatively peanuts for what you get and SCCM \ SCVMM (if you're using Hyper-V) will be well worth the investment. Maybe try and build a 3yr license into the project costings if you can't be sure of budgets year on year.
For web servers and the like CentOS Linux is awesome :)
Looking at what you want to do, as everyone else has said you should be fine, we've worked quite a few people to consolidate quite a few physical boxes on to a handful of nodes and it works quite well providing you plan out your spec - especially your storage (PM if you have any specific questions), i would recommend at a minimum if you are unsure, running the MAP tool kit to get an idea of how much your existing infrastructure is getting hammered to make sure you get the right hardware.
Depending on your host specs, the licensing cost will obviously vary, a 2 Proc license of Server 2012 Datacentre is around £165.00 (iirc) on EES which is a small price to pay for unlimited VM's.
One thing I would also look at is how you are backing up all your hosts and what your DR plan is.
As gshaw says, depending on how many seats you have, utilising some of the SC tools may be a good idea (DPM for example will work well in an all MS environment) and depending on your EES licensing you may already be licensed for the clients.
We’re going through a similar exercise and re-structuring our server rooms, but are taking a different route. We are currently running two file servers, to share the workload and provide redundancy, as we can move the users to the other server if one failed. However we have audited our sever performance and found that the file servers are working at a fraction of their capacity, and having each server acting as a back-up for the other adds a layer of complexity.
We are actually planning to go to a single file server and use the second purely as a stand-by. It greatly simplifies data replication and management of user home drives. Using some of the new shared storage and the replication features in Server 2012 we are confident we can get instant fail-over to the stand by server. We are also planning to use VM replication to provide a similar set-up for our virtual hosts (i.e one live and one for fail over).
Our servers are Prolient DL380s (G5s, a G6 and a G7) with duel Quad core CPUs. We are going to have to increase the memory on the virtual host.