Mini-Mac Server as an NAS

I have been wanting to start digitalizing my music and placing it on a server.
I have a Mini Mac Server that I have been using for my business that I am replacing with a Windows Server (the programs we run are Windows based and the problems that we have had with the software to convert Macs to virtual Windows Machines have been so problematic that that they have almost closed us down). I was wondering about using the Mini Mac as a home NAS, since I would like to get some use out of it and since I otherwise have a Mac based system at home.
My main concern is this: I need about 4TB, and the Mini mac Server has 1 TB, configured as 2 500 MB drives in a RAID config. Can I add extra drives
and have them work seamlessly?
4TB: Wow, you got quite a music collection! Let us know how long it takes to rip that much music.

I have a couple of thousand CDs. Some of these are SACD and DVD-A and I won't be ripping these but I would like to get rid of the bulk of my collection so that I don't feel like I am living in a CD warehouse. I figure 4 TB will handle the collection and leave enough room for new acquisitions.
I kind of expect that the ripping process will take a few years, during which time I can reconnect with a lot of music that I haven't heard in a while.
What is "concancinated"?
You can rip DVD-A discs and get the hi-rez PCM. Also, when Herman mentioned concatinated he's probably using software that acts as a "volume manager". Multiple drives can be used to present one sum-of-the-parts big drive to the user. And usually you can add drives to make the volume bigger over time.

If you plan to make a big volume of some sort and it will be over 2.2TB, make sure your O/S can handle it. I would think current Apple O/S can do it and Windows 7 can do it (and linux). And also be careful that there are new disks that are being sold now that use 4K physical sector sizes and use software in the drive to do 512 byte sector emulation for the O/S. Stay away from them. And I believe there are some type of "hybrid" drives out that have 4K sectors and somewhat large solid state caches to help overcome the performance degradation of 512 byte emulation when using physical 4K sectors. Stay away from them also.


Apple Osx disk utilities has functions built in to build disk arrays

From Mac disk utility help files

About concatenated disk sets

You can create a single, large disk from several smaller disks by creating a concatenated disk set, which is also called “Just a Bunch of Disks” (JBOD) or “spanning.” The concatenated disk set acts as one large disk with the combined capacity of all the smaller disks. You can increase the size of a concatenated disk set after it’s been created by dragging more disks to it using Disk Utility.

A concatenated disk set is helpful if you have a file, such as a database, that’s larger than any of your disks. It’s also useful if you need to create a mirrored or striped RAID set with one large disk and two smaller disks.

If all the disks in the RAID set are about the same size, consider using a striped RAID set. A striped RAID set lets you access your data quicker.

Be sure to back up your data frequently. If any one of the disks is damaged, you will lose the data that’s on all the disks.

Wow. This is great. I will have to further investigate "concatenation" (to coin a phrase). It sounds like what I've been looking for.
Any suggested references? I wish there was a Dummies book for this (I've looked and there isn't).
Another newbie question: I understand that most NAS do not have any disc ripping abilities. My understanding is that one can use their pc to perform the rip. What I'm wondering is if the NAS software allows the pc to rip and store on the NAS without having to store it one the pc? I know that I can ultimately delete
the files from the pc, when I don't relish the thought of deleting thousands of CDs from my pc.