Help with Raid 5 or 10

I have been building a custom PC the last couple of weeks with the help of these forums. After some discussion it was suggested to me that I scrap what I was doing and build a Raid 5 system. So everything is on the way from Newegg and now I have some additional questions. I have ordered 3 Western Digital Caviar SE16 WD7500AAKS 750GB 7200 RPM SATA 3.0Gb/s Hard Drives for my system, and I have a PK5 deluxe Asus mb. I have been doing some additional reading, and it everywhere I look it seems to say that RAID 10 is the better way to go. I am running a powerful PC not for gaming, but multitasking and running a SQL database. My questions are:

• Should I buy the extra drive and run Raid 10 instead?

• The mb says that it supports Raid 10 on the southbridge, but when I look up additional information in the user manual, it only talks about Raid 0 & 1 http://usa.asus.com/products.aspx? [...] 3=534&l4=0. I am a total newb at this so I don't really understand how to do this. Do I need a Raid controller card which ever way I go? Or is this something that can be done through my mb?

Any help and direction will be greatly appreciated!

In a raid 1+0 setup it would go something like this:

Drive 1 - (Raid 0) - Drive 2
| |
(Raid 1) (Raid 1)
| |
Drive 3 - (Raid 0) - Drive 4

You'd need at least 4 drives, the first Raid 0 (Drive 1+2) would be the only one visible and usable on the OS. So with 4 750GB drives, you'd only be able to use 1.5TB of space, the second Raid 0 (Drive 3+4) would be a constant mirror of the contents of the other Array. So for example if Drive 2 failed, Drive 4 would take the place of Drive 2. That's also the case with Drive 1 and 3. A failure of both 1 and 3 would render the data in the remaining 2 and 4 completely useless, and vice-versa.

A raid 10 setup does have its performance advantages, but the problem is the cost of the hard drives. Since both performance and reliability seem to be your need then I think that Raid 1+0 could be for you.

Raid 1+0 is supported in your board, it's just because Raid 1+0 is not an "official" Raid type.

I don't know anything about setting up a Raid 1+0 setup since never really had the money to do it, I think other people might have a clue. I think your board should have either a utility in the BIOS or you'd need to press something like Ctrl+A (Ati Xpress200M boards) to get into the Raid menu before booting into an OS.

Tell us more about the planned SQL server implementation. What kind of databases are we running here, and what kind of transaction load is it going to have? (i.e. number of simultaneous users). What size are these databases?

With a low user load, probably low transaction load, and databases that aren't very big, I would say you're in the territory where it doesn't really matter.

The 3Ware card will do RAID 5 just as well as it will do RAID 10. (I have that same card and it's very good).

Since you bought the 4th drive, I'd go ahead and set up RAID 10. This RAID should be a data drive only, your boot drive should be on a 5th drive.

For extreme SQL server implementations, I have seen some where you establish 2 RAIDs, and put the database files on one and the transaction logs on the other. I don't think you need to go to that step.