Why do people have multiple servers?

radiogoober

macrumors 6502a
Original poster
Jun 7, 2011
972
1
Hi all,

I sometimes see pictures where people have several servers all racked up. There's even products to rackmount up to 18 Mac minis. My question is: why? What are they using this for? How could you harness 18 Mac minis for a purpose? Is this for like distributing computing? Or is perhaps each mini doing a single thing?
 

GeekGuys

macrumors regular
Mar 13, 2009
146
5
Various reasons.
1. Processing power to run multiple applications
2. Apps don't play nice together, so need separate machines
3. you don't want one app bringing down another, so you run them on separate machines
4. Multiple versions of the same app for resilience (ie, one dies, the other continues)
5. You have a megamind complex and really like racks of flashing server lights, just like in the movies?
6. More money than sense.

If you have ever run a video ripper, or processing app, you will know that a single computer can easily run at 100%. So, if you want to run anything else at the same time, you need to spread your applications around multiple physical (or virtual) servers.
 

guzhogi

macrumors 68040
Aug 31, 2003
3,017
896
Wherever my feet take me…
To expand further, for businesses, all the things a business runs is just too much for one server. I work in a school and in my district, we have over 4,000 students, teachers & staff. We also have over 2,000 computers. We use servers for:

-Open Directory for user accounts
-Library automation (ie checking books in & out)
-Computerized testing
-file sharing
-reimaging computers

and more stuff. One server can't do that all. Plus, some stuff is Mac only, some stuff is Windows only, etc.
 

dyn

macrumors 68030
Aug 8, 2009
2,708
384
.nl
And obviously for things like high availability (because you have redundancy) and load balancing (spreading the load over various machines).
 

radiogoober

macrumors 6502a
Original poster
Jun 7, 2011
972
1
Let me ask this question. How does redundancy work? For example, if I have a Mac mini server, and it's configured to be a Mail server for a 10 computer network, how would a second Mac mini be setup to be a "backup" or "redundant" Mail server? Would you just configure it identically and magically it works? I guess I just can't comprehend it.

(I'm not setting one up like this, I'm just truly interested in how this works.)
 

ChristianVirtual

macrumors 601
May 10, 2010
4,096
266
* ** *
Sometime business have "funny" testing requirements like
First start in development system; copy over into a quality assurance system before setting a change live in production. Add: testing and training environment plus failover ...
Pharma is such an environment; aerospace and others too.

Opps: sorry; thread is already a bit older :eek:
 

belvdr

macrumors 603
Aug 15, 2005
5,660
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No longer logging into MR
Sometime business have "funny" testing requirements like
First start in development system; copy over into a quality assurance system before setting a change live in production. Add: testing and training environment plus failover ...
Pharma is such an environment; aerospace and others too.
That should be the case in most enterprise environments. Many outages have been caused by testing in production.
 

calaverasgrande

macrumors 65816
Oct 18, 2010
1,291
161
Brooklyn, New York.
In ad agencies and some other digital media companies I have worked for we always have duplicate Development (DEV) and Production (PROD) set ups.
So for a simple website we may have one system running MySQL/PHP, and another running Apache. Then times that by two.
This can grow to several SQL computers if you are running something like a website with a members database, a forum database and the websites own database. While it is certainly possibel to put all of those on one server, it will run faster and be more scalable if you put each on its own server.

And then on top of all that we will often run a management/console server which is just a local desktop/laptop that you can use to manage all the servers without hooking up a monitor to them.

A year or so ago I had a Domain controller, a webserver and a database server set up in my closet. That was mostly PCs and Linux though.
 

neil1980

macrumors 6502
Nov 1, 2008
412
17
We have approx 40 PC workstations running some bespoke parts software... it Needs a main data server for running all the databases and then 2 application servers which help load balance the 40 odd work stations with the main data server.

Then we've got a web server, it also connects to the database on the data server for online orders.

And a file server which also runs the call monitoring software for the phone switch board.... it could all go on one of the app servers but it was decided t keep it entirely separate from the bespoke software.

And finally an ancient server thats only job is to be the server for an old version of sage that won't work on server 2003 or newer...so instead of upgrading sage for the very minimal useage it gets (I believe we only use it for tracking holidays) it was easier to keep it on its own server.


So theres a smallish business and its already running 6 servers. If you have a few thousand users instead of sub 50 its easy to see how you could easily fill a few racks
 

calaverasgrande

macrumors 65816
Oct 18, 2010
1,291
161
Brooklyn, New York.
which is why a lot of us are going with blade servers. It is a significant upfront investment. But you get more computing per watt, and a space savings.
I'm secretly scheming to get a blade system for our domain controller refresh next year.
 

belvdr

macrumors 603
Aug 15, 2005
5,660
1,022
No longer logging into MR
which is why a lot of us are going with blade servers. It is a significant upfront investment. But you get more computing per watt, and a space savings.
I'm secretly scheming to get a blade system for our domain controller refresh next year.
I'd get blades and virtualize those.

Only potential issue with blades besides cost is the power requirement and having enough cooling at the front of the chassis.
 

tillsbury

macrumors 65816
Dec 24, 2007
1,416
345
Also, the company will need at least one server for administration -- from letters, emails, to accounts. These servers will need to be completely and utterly separate from anything dev can get access to, otherwise they'll be down more than they're up!
 

Nightarchaon

macrumors 65816
Sep 1, 2010
1,393
29
Various reasons.
1. Processing power to run multiple applications
2. Apps don't play nice together, so need separate machines
3. you don't want one app bringing down another, so you run them on separate machines
4. Multiple versions of the same app for resilience (ie, one dies, the other continues)
5. You have a megamind complex and really like racks of flashing server lights, just like in the movies?
6. More money than sense.

If you have ever run a video ripper, or processing app, you will know that a single computer can easily run at 100%. So, if you want to run anything else at the same time, you need to spread your applications around multiple physical (or virtual) servers.
Number 5 for me all the way, i LOVE flashing lights
 
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