How many servers do we really need?

[dgsmith]

A bit of background:
RM CC4 network
3 AD servers (FR + 2x DC)
Approx 340 desktop/laptop clients
710 students, 75 staff

The question is about the main servers which handle logons and user areas and generally the backbone of the network, as opposed to member servers (such as SIMS, intranet, filtering etc).

We currently have 3 servers, with 2 of them being long overdue for replacement (3rd server purchased '04, 2nd server '05). We are wondering whether it would make more sense (financially) to replace servers 2+3 with a single beefy server that has more power than any single server would normally have?

My thought is that, if we really go the whole hog then we'd be looking at 130% the cost of what we'd normally pay per server, but would this route be viable or would we notice any drop in performance regardless of how powerful the server is?

As RM charge hardware and software support annually per server, and we're looking to cut our energy bills too, this is something we are considering. We're not in a position to consider virtualisation and we have no SAN (pretty much a very basic network setup).

We normally go for SATA HDD so i'd imagine we'd look to get 15k RPM SAS HDDs and utilise the dual network ports for added bandwidth.

[daz191]

We currently have 700 computers on our CC4 network, using just 2 servers (FR + 1 DC), so you should be ok downsizing.

[Brpilot99]

Having 2 DC's rather than just one has the advantage if one breaks in a big way then its easy to restore active directory to the new hardware ..... bring up as a member server then promote to a DC and active directory will auto replicate to the new DC ...

[dhicks]

We normally go for SATA HDD so i'd imagine we'd look to get 15k RPM SAS HDDs and utilise the dual network ports for added bandwidth.

You can team up to four network ports, so you might as well get a server with four or five network ports just to allow for future expansion. I'd go for larger-capacity SATA drives and a decent hardware RAID card instead of SAS drives. You don't need a SAN, a decent server with on-board storage is just fine - you could use one of your old servers as a backup if you could stick some more disks in it.

[dgsmith]

Thanks for the replies. The main reason we went 3 servers originally was because when we got a new FR, we knew this would be it for quite some time due to no money (3yrs ago), so figured we'd be better having 2 older servers to share the additional load than just 1 older backup server (and also as these are now more prone to failure). There is pressure to reduce ongoing annual costs so we need to really know whether we can afford to go back to 2 if we get quite a high-end one.

Looking back at previous orders and doing a google search, it does seem going SAS is better? Quite a bit more, but then is it not better to get the best you can? Definately want to look to teaming, but would this make any real-world difference to performance of the network if this server is to be a secondary one?

daz191, do you find 2 servers with that many clients is ok? I'd have thought for that size network at least 4 DCs would be a minimum necessity!

[daz191]

daz191, do you find 2 servers with that many clients is ok? I'd have thought for that size network at least 4 DCs would be a minimum necessity!

Runs fine.

Although the old Celerons with 512mb RAM are quite slow, but I can't blame the servers for that!

RM always under estimate how many PCs that can be supported per server. When we switched to CC4 last summer we had the 2 new servers commisioned, with the intention of getting a third server this year if required, which it's not.

Like you said, it's the extra support contracts that add up over the years so you're better off going for a higher spec server and less of them.

[Mr.Ben]

I purchased a server last year to replace the jobs of two which were overloaded - The cost was £3600 for a 12 core 24GB RAM beast with 4 Network Ports.


I've dropped Windows 2008R2 Core onto it and run 4 separate VM servers each with there own dedicated network card. One of these is a DC (i have 2 on site), 2 are members (one SIMS, one WSUS and all of my management tools/Databases) and the other is currentely spare, but I intend to use it as a web server

[sukh]

Hi

For your Domain Controllers, I'd recommend at least 2 for HT/FT. I know you mentioned that you're not going to virtualise so you should be OK. If you do then, you need HA/FT for the host. Some don't mind and will promote another member server in the AD, however, this is acceptable if you can tolerate the downtime which I don't think any school can.

If you do decide to go for a high end server then you may be able to use as a guest if and when you virtualise.

If you want to true metrics on DC usage then you should gather some performance stats and then spec your new server.

I also, assume you only have one site and one AD domain? Need to consider this too for your doman controller placement/deployment.

Sukh

[Butuz]

2 DC's should be all you need (assuming they are decent spec I.e Dual quad core 4GB or more RAM preferably 10 x HDD in Raid).

Butuz

[zag]

I run 2 DC's with Pentium 4 processors on our network with 450 clients.

Never seen it go beyond 20% usage. It is on a vanilla network though.

I would always have 2 DC's though for failover purposes.

[dgsmith]

Well we're looking at 2x quad core E5640 2.66ghz (new westmere), 8GB RAM and we're pondering 4x 300GB SAS in RAID 5, which I think gives us just shy of a terabyte HDD space. Our current Server1 has 250GB usable space, and servers 2 & 3 have 200GB each roughly of usable space, so 900GB seems like a massive step up.

Single site and although we have a separate admin (SIMS) domain, this is setup on trust and no clients use this domain. I suppose the spec above should also be enough should we ever wish to go to a virtualised route in the future (we want it to be future proofed too)!

[jamesfed]

Might be a bit overkill for your needs but I'd suggest you take a look at a SAN and going virtual again.
The SAN on the grounds of with that number of students you could come accross a situation one day where you need to expand your storage easily and with the VMs as it will make you more flexiable in the future should your schools IT needs ever change.

Also do you have a rack or if no the space for one (even if its just 15U)? Again maybe a bit overkill but a pair of HP DL165s (8 core high eff and maybe 8Gb of RAM) with a Qnap Nas in the background for your SAN.

[Butuz]

Assuming you want to stick physical - I would go for more, smaller drives in each server rather than few, larger drives. E.g instead of 4 x 300gb go for 10 x 160gb and keep one as a hot spare. This will yield roughly the same capacity but will be MUCH faster in use and more reliable (hot spare is a REALLY good idea if you don't like downtime or performing full server recoveries).

Other than that - looks good!

Butuz

[sukh]

@Jamesfed - SAN is good only if you have DR for SAN, what happens if controller/CPU goes down, or the fabrics, fibres, switches etc...

And that is expensive!
Sukh