To start, let me try to explain RAID as I think this may help everyone understand the other things we have been saying:
RAID = Redundant Array of Independent Disks; it can also be inexpensive drives or independent drives, but the first is what is generally used.
The reason for raid is for data reliability and increased performance. RAID creates a virtual disk using multiple hard drives either by a software controller (OS) or via a hardware controller. A hardware controller presents the drives as a single unit and the OS is not even aware. It sees it as one drive. A software controller does the same and the OS still sees one drive, but it can also detect the single volumes. The difference is easily seen in computer management.
If a software controller is used (by using the OS software), the possible RAIDs are determined by the OS used. As stated earlier, XP Pro cannot created a mirror or striped RAID unless it does this remotely to a server OS. Server OSs also can create software RAIDS and are generally not limited.
RAIDS allow three things:
Mirroring, which means that two disks are exact mirrors of each other. If one drive fails, then the computer will continue to run without any loss of data or speed. Obviously, since the mirror is "broken," you will need to replace the drive ASAP. The drive will be rebuilt rather quickly and there will be no hiccups in your performance. The downside to a mirror is that while reads are fast, writes are slow, because the OS must write to two different drives simultaneously. Also, you ALWAYS lose 1/2 of your hard drive space.
Striping:
In striping, you use multiple disks and stripe data across them. So, you may have data spread across four disks. This allows very quick read/writes, therefore, increased performance and extra fault tolerance as you would see in RAID1 (mirror). If this were the only setup, then the loss of one drive would mean a complete loss of your data, but the final drive is used for parity. This gets confusing, but just take it on face value. The parity keeps track of where data 1, 2 and 3 are on each drive. In this way, if you lose one drive, the parity will allow you to rebuild that drive. Disadvantages include your system will slow down if you lose a drive and it takes longer to rebuild. But, you have much more space, because you combine all the drive space minus the parity drive. So, four drives gives you 3 times X for 75% of total, while five drives gives you 4 times X for 80% of the total and so on. This is considered a RAID5.
Anytime, you lose a drive, you add another to the computer and the RAID controller will automatically format and rebuild the drive. There are really cool setups called hot swaps, where the hard drive can be slid in while the computer is still running, and you do not miss a beat. There is also a system called "hot spare" in which the drive is already in the computer so if your drive failed during the weekend, the hot spare would be configured automatically. You would still need to replace the drive. But, I digress.
There are many, many RAIDs, but we generally talk about RAIDS 0, 1, 5 and 10.
RAID0 is simply a striped set of two drives which improves performance but does not increase fault tolerance at all. Lose a drive and lose your data.
RAID1 is a mirror. Very common among IT professionals.
RAID5 is a series of striped drives. Many people use this for redundancy and performance when they have a lot of data they wish to protect.
RAID10 = RAID 1 + 0, which is a two mirrors then striped together.
RAID 0 + 1 = two striped drives that are mirrored. Efficient but not nearly as good as a RAID10.
Certainly, don't worry about a RAID10 (or any of this for that matter). Also, remember that even though these RAIDS increase performance and allow for one drive to fail and in some instances two if using a RAID10 and the right drives fail, the more drives you have, the more likely a drive failure.
OK, that is a summary of RAID. A general rule of thumb is if you don't understand it, you probably don't need it. Sorry, to be harsh -- or at least someone else should set it up for you.
To summarize it sounds like XP pro can support some RAIDs with a hardware RAID controller. Is this a card one puts in a tower with extra hard drives to act as synchronous backup? Or is RAID something else. (sorry for the naievity)
With that behind us, Gary: just about any OS can support RAID if a hardware controller card is used as it is independent of the OS. Certainly this is true with XP and 2000, although there is some amount of software the OS needs to interact with the controller.
The card is put into the computer just like a PCI or PCIe card. It can't be any old card. It has to be compatible with your motherboard. The hardware controller can also be on the mobo, and it will function just fine.
It should not be looked at a backup. Yes, the mirrors are the same while the striped drives are not. But, in a backup, if you do an actual backup of your system on Monday, and on Tuesday a file becomes corrupt or someone deletes a file or folder, you can go to the backup and get it back. With a RAID1 (mirror), if you delete a file, it is instantly gone from both drives. If data becomes corrupt it is corrupt on both drives. So, a mirror should NEVER be looked at like a backup. It should be looked at as redundancy so that if a DRIVE crashes, you do not lose all your data. You do not have to spend the entire weekend reinstalling your system and praying your backups are good. You slide in another drive and you are ready to go.
My final statements:
Much has been stated about RAIDs here (my talking the most). The original question was "I have two PCs. What is the best way to set up my office." How we got on RAIDs, I don't know. To me, the difference between understanding RAID technology and/or setting it up and setting up a peer-to-peer network or simple pseudoserver setup is like the difference between calculus and long division. (Granted I forgot that a long time ago). And, maybe I am overstating the difficulty of RAID.
These are some truisms (that only come from my opinions):
If you are setting up your database and your network on Windows XP Pro, then you probably shouldn't be setting up RAID. RAID, for the most part, is for server OS and actual servers built to be servers. They are generally used on domains but not always. I am not saying you can't do it on XP Pro, but it doesn't seem to make sense to say I am going to use what I have and keep my budget intact and then go out and purchase four or five hard drives and a controller card. One would be better off setting up a very good backup system.
More and more people are setting up RAIDs at home on Windows XP Pro or Vista. But, very few people with a "Small Business" with important data are using RAIDs on XP Pro. I am not mocking anyone using XP Pro, we used a server without a domain at my last job for over six years. But, hey, get two fairly identical hard drives, get a cheap hardware RAID controller compatible with your computer and your SATA drives, which means your computer has to support SATA drives, and set up a RAID at home. Do a RAID1 and break the mirror, then put it back. Do a RAID5 and pull out a hard drive and see if it still runs then format it and put it back in. Experiment first at home.
Hope this helps. If anyone really wants to install RAID, then get a good IT guy or you can contact me or others on the board familiar with RAID.
