I'm looking into building my own home server, w/virtual OSes on it, others in my house aren't too keen to Linux. My question is, when I build my server, do I HAVE to use a RAID mobo,or can I use a regular modo? If RAID, which one?

Nothing compelling you to use one in the slightest. Why did you think that might be the case? Linux provides great software raid if you want to use it.

Hi and welcome to LQ.

You don't have to use a motherboard with hardware RAID support. Why would you HAVE to? The choice of RAID depends on you and is dependent on a number of factors, eg. the number of hard drives you have available. Here's a short description of RAID levels:
http://www.chicago-data-recovery.com/raid-levels.php
http://www.petri.co.il/raid-levels-comparison-guide.htm

what if I want my server to have, say, 4 1TB HDDs? I was told that If I run a server, it would have to be on a RAID, & was advised to get a mobo w/RAID 5 support.

If you want to have 4x 1TB then simply plug in 4x 1TB. Having a RAID is not necessary. RAID was invented to create servers with high availability, so if a harddisk dies that you can work while the new disk is plugged in and the RAID re-created. It is not a necessarity, and regardless what some people say it is not a replacement for backups.
Even if you want to have a RAID array you don't need to buy a board with RAID support. Linux is totally capable of creating RAID arrays in software. No need for expensive hardware.

Sweet!! I appreciate it. This saves me a k when I build my server! Thanx!!!!

Although Linux can provide software RAID, a true hardware RAID will put the work for parity creation and for rebuilding the array off the CPU and use a dedicated controller instead running independent from the system.

Did I get you right, that you want to run virtual machines on this system? Then it’s a question where to run the software RAID. When you run some hypervisor on the bare metal (e.g. VMware’s ESXi), I think you must go for a hardware RAID. It’s best to check beforehand, which controllers are supported by the hypervisor right now.

When you run one Linux instance as the main operating system and create virtual machines thereon only, a software RAID will do though.

NB: Just to note, that some mainboards advertise RAID functionality, but they provide only a so called fake-RAID (check for Firmware/driver-based RAID therein), i.e. they support booting from the RAID, but later on they switch to a software RAID in the driver of the disk.

ok, Just so I get this right....If I want to make a home server w/multiple virtuals & TBs, I will need to make it a RAID, but get a regular mobo w/a Raid controller card? Or would just a regular mobo w/ubuntu creating the RAID?

no, you don't *NEED* RAID ever ever, it'd just a wise thing to do.

ok. If i do make a RAID server, I am suggested to use RAID5. Which should I get, a RAID mobo, RAID mobo w/controller card, or Regular mobo w/controller card? I just want to know, so I'm not spending unnecessary $.

you don't need any special hardware at all, software raid works very well.

Personally I don't like raid 5, it's very often just the cheapest way to get some level of resilience, but it can be very inflexible and such. It's very easy to add another RAID1 pair to a system, adding another disk to RAID5 is possible, but not at all fun.

RAID boards, non-RAID boards, both will work with a hardware RAID controller card. The good ones cost a lot, the cheap ones arent worth looking at.

The 'RAID' boards can be of 2 types- 'standard' intel/AMD HDD controllers with an added RAID controller, or a intel/AMD controller with RAID enabled. All the current AMD southbridges support RAID, intel varies with model as far as I know. You dont want to use intel, AMD or any 'addon' RAID chip though.

Just a 'regular' board will do the trick. If it does have RAID from a addon controller chip or from the AMD or intel controller, dont be temped to use it- linux software RAID is better IMO.

IMHO, I recommend starting with one disk, one partition with the operating system on it. Later on, you can move the disk's data into a RAID or whatever. After a while, you'll discover RAID is one more thing to babysit. But, I've been at it for a little while now...

As a general rule, if this is your first effort at building a server, keep it simple because the learning curve is steep. Don't bother with most of what is marketed as "RAID" equipment. It's mostly fake-raid. Fake-raid is essentially a software raid burned onto an ASIC. A hardware RAID card as an add-on is going away because computer hardware is plenty fast enough for an in-kernel RAID.

Also keep in mind most serving can be done with very little computing power. I have a dual 500mhz machine still going strong from way back in the day that hosts plenty of home-type services (including a software RAID), some even connected to the Internet and there's no meaningful strain on the resources. The network is a big constraint on serving data.

Finally, I'm a Debian user. It works for me and has many, many different servers in their repos. Therefore I suggest starting with that distro. YMMV.

+1 on don't bother with a RAID for your home server, especially at first. It is one more thing to worry about, install, and manage for an incremental increase in up time. Not to mention, as you noticed it is a lot of extra expense.

ok, I think I got the just of what I need to build a home server. Now for the clients, do their computers HAVE to have an OS on them, or will the OS load as long as they boot via network & connected to the server? Yes, that is a serious question. If they HAVE to have an OS on them, does it have to be the same one on the server when they boot up via network, or can it be whatever the user desires?