Implimenting NAS, how do I estimate the storage needed?

[WestCoastKid]

We are probably going to add a raid array to our network. How do we calculate what size array we will need? Same goes for the back up device.

I appreciate your help.

 

[comtec17]

Are you sure you need NAS? What is it that you are wanting to do or accomplish?

To size an array, you will make one of 2 choices, do you want throughput (I/O) or bandwidth (MB/s). A typical 10K RPM drive will give you about 100 I/O per/second per spindle. If your application needs to have 1000 I/O per/second, you will more than likely need 11 - 12 spindles.

There are a ton of capacity planning documents out there, but you really need to understand what all of the drivers are for you to choose this method.

 

[WestCoastKid]

We've outgrown one of our servers internal storage and instead of upgrading disks, we would like to add an external disk array. Now then we will also be backing up somewhere around 8-10 workstations which we were not previously, with the server we've outgrown and I need to know how to figure out just how much storage I will need to purchase.
It's simply a file/print server nothing more.

So is there a formula or rule of thumb etc for a situation like this?