TPOV

Today, Microsoft or better; the Microsoft Exchange Product Group released a new version of the Storage Calculator for Exchange. In good Microsoft fashion, this version has been renamed. It’s now called the “Exchange 2010 Mailbox Server Role Requirements Calculator”.

That new name should better cover the tool’s use…

But when would you be using this tool?

Let’s say you would have to buy a new Exchange 2010 Server for a small company of about 40 users. Since one has limited financial resources, let’s assume you will combine all required Exchange roles onto this one Exchange 2010. (Mailbox, CAS and Hub). Let’s say these 40 mailboxes are accessed by 40 ‘heavy’ users, and you want to give these users a 1GB mailbox, with a 10GB archive.

Without doing a lot of math you could imaging having at least 440GB of storage available to the server. And you will need some storage for the OS, let’s say 15GB. Some logs… not to mention… 45GB? That Ok with you? So if you would have 500GB of storage everything is still good, right?

Since you will buy only ‘the standard’ server for your organisation, you might end up with a DELL PowerEdge R710. Since budget is limited, let’s say you buy this one server with one quad core CPU and 8GB of RAM. That’s not really that exotic a server, is it?

Since we cannot afford the Exchange HA solution (requiring a few Windows Enterprise Servers) and therefore cannot go with a ‘backupless’ solution, we won’t be using the ‘cheap storage’. In stead, we use the fast 15KRPM SAS Disks in a RAID configuration. We’ll put 6 of these disks in the server, each capabale of holding roughly 300GB of data. We’ll configure a RAID5 set of four disks for the databases and a mirror or two disks for the logs. But hey, let’s see if the Calculator can give us more insight on the disk configuration to use!

Such a server would set you back about €5.000 (with redundant PSU, DRAC Management card and some DELL support).

So would this ‘standard’ server suffice for these 40 mailboxes? Or; how many mailboxes for how many users can I put in this machine?

First of all, the Storage Calculator tells us that in this configuration the server is really doing completely nothing. Nothing! It’s IDLING… Yet, it recommends 11 300GB SAS 15KPRM disks. 9 for the databases in RAID5, and 2 disks in a mirror for the logs. Tss…

So we yank up the number of users to 100. Since we only have 900GB of available disk space for the database, we will give the users a 1GB mailbox with a 5GB archive.

Well.. that doubled the CPU Load! (From 1% to a whopping 2%. If you’re heavy on the mouse, you might hit 3%!) and it now recommends using 14 disks.

If we crank up the number of users to 250, and leave the messagebox size untouched, we see that we don’t have enough disk space to accomodate for all these users. But the CPU load is still at 5%.

Obviously, we don’t have enough storage to accomodate for 250 mailboxes of 1GB with 5GB of ‘personal archive’. But what did it do to the performance of the server? It’s still doing nothing. Perhaps 5 to 8% CPU load.. Duh… and it yanks up the number of disks, ideally, to 29 (!). Oh yeah, the calulator tells us you might be better off putting 12GB in the box in this situation.

So what does this tell us?

The Storage Calculator is a great tool. Especially when you are sizing mailbox servers for about 25.000 users or more, with a ‘large’ mailbox. It gives you insight in the working of the Exchange server roles, the overhead involved (a 10GB mailbox WILL require a lot more then 10GB on disks!) and a lot, A LOT, more of VERY USEFUL information.

In our scenario, a VERY common scenario in Europe, up to 100 heavy users on a single multi-purpose Exchange server, you will ALWAYS have enough performance if you buy a decent new server. The only problem you might encounter in this situation is that disk space is running out. CPU and Memory will hardly ever become a problem. It’s just disk space you are running out of! Seems to me like it’s very hard to ‘overload’ a regular, main stream, rack mountable server. Yet, you will have to invest in some sort of backup solution still. Perhaps the Built in Windows Server Backup with the Exchange Server plugin will suffice. If you add all these things up, you might end up with a solution that will set you back around €10.000 in hardware, and about €4.000 in software licenses. (2x Windows Server Standard, 1x Exchange Server 2010, a few CALs and a Backup Solution running on the second server.) You will have to put these servers in the books; so in our 40 user scenario that would be just under €10 per user per month when you write off these servers in 3 years. And that is even without the management cost! Therefore the Microsoft Online BPOS offering might be a good solution…

So the tool is AWESOME. But it’s not for me.

Get detailed information on the new Storage Calculator and a download link here.

IMPORTANT: If you are not running in a valid ‘backupless’ environment a JBOD configuration of disks is NOT RECOMMENDED. In the scenario’s mentioned here, it is BEST PRACTICE STILL to put your log files on a mirror and your databases on other (protected) spindles, for example RAID5. In ‘our’ server that would mean that you will put the databases on a RAID5 set of 4 disks (giving you 900GB of raw storage) and the logs on a mirror of two disks.