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Using RAID on Intel H67 Motherboard.


kylejwx
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First of all, my technology budget for this project is $0.  I know that I could do much better with a RAID controller or an SSD or many other solutions, but these are not an option as of now.  Part of the fun for me is getting creative with what I have, which is a 2.5” Hitachi 320GB hard drive and a 3.5” WD 320GB.  I also realize that setting up RAID might not be necessary or ideal, but I have never done it before and I just want to do it for fun and experience.

 

I want to accomplish two things: install Windows 8 Pro and set up RAID.  Will the H67 motherboard based RAID allow me to use these two different drives?  I understand that identical drives are preferable.  I just need to know if it is possible.  If not, I might just mirror the drives in the OS.

 

By the way, what is the performance difference between just one drive, a RAID 1 mirror, RAID 5, and RAID 0?  For some reason I am assuming that I have listed these from slowest to fastest, but correct me if I am wrong. Or perhaps it is more that RAID 1 and 0 provide a similar performance increase, but 1 allows for resiliency and 0 provides more storage?
 



Current os drive speeds.cdriveATTO.JPG

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RAID 0 is fastest, then RAID 5 then RAID 1. A single drive should be the same speed as RAID 1.

 

With two drives you could do RAID 0 or RAID 1. Chipset RAID is not very flexible, differences in the drives could cause issues.

If you are looking for speed, set up a RAID 0 and see if it works.

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Well I was hoping to get resiliency and at least a little bit of speed increase with RAID 1. I guess testing it until it breaks might be the best option. :)

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First off you will be limited to 0/1 with only two drives.  Raid 1 is really the only way to go in your situation as RAID 0 would be very dangerous.  Not resiliency, unlike drives, and using a motherboard controller are not a great combo.  Your question on unlike drives is that yes, it will work but highly not recommend.  If you really want to RAID, go with a mirror configuration as that is the most forgiving.

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Well I was hoping to get resiliency and at least a little bit of speed increase with RAID 1. I guess testing it until it breaks might be the best option. :)

Is this something you intend to put into production or will it just be for trying and learning?

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With RAID, performance does depend on what you are doing with it. Now the three RAID levels mentioned by the OP are 0, 1 and 5, they all work very differently to each other, each have pros and cons and which one you choose will depend on your circumstances and what you want to do with your data. 

 

So RAID-0 which is arguably not really a RAID level at all as there is no redundancy in it  (the 'R' in RAID), otherwise known is disk striping uses two or more disks and data is written sequentially to them. Imagine that you need to write the numbers 1,2,3,4,5 to a RAID 0 array, 1 is written to the first disk, 2 is written to the second, 3 is written to the first disk again and so on. Performance, in theory, especially for reading data is very fast as each disk could (depending on the controller hardware) be reading and writing sequential chunks of data at the same time. However if either of the disks fail then you have lost all of your data as there is no way to recreate the missing data from what is left on the other disk(s). On the other hand if raw performance is the most important thing then this setup would provide the best solution and also there is no storage overhead, if you stripe two 1TB disks then you effectively have 2TB of usable space.

 

RAID-1 or disk mirroring uses two disks in such as way that the same data is written to both of them, so in our example 1 is written to both disks then 2 is written to both and so on. One whole disk can fail and you still have all of your data intact but you do effectively loose 50% of your disk capacity, i.e two mirrored 1TB drives would only give 1TB of usable space. Read performance is fast (but generally not as quick as RAID-0) as again depending on the hardware, both disks could be reading data off in parallel. Write speed is no better than a single disk and often a bit slower as two write operations have to be made for each block of data. For best performance you would want a hardware system with each disk attached to a separate disk controller (a feature sometimes referred to a disk duplexing).

 

RAID-5 is the other commonly seen arrangement (yes there are RAID levels 2,3 and 4 but these are not often seen in the wild). RAID-5 is also called disk striping with parity and requires a minimum of three disks (again ideally running off of separate controllers), and it works something like this. 

Again we want to write the numbers 1,2,3,4,5 to a RAID array of three disks, 1 is written to the first disk, 2 is written to the second disk and then a mathematical calculation is performed on these two items of data to produce a parity number and this is then stored on the third disk, for example the difference between 2 and 1 is 1 so a 1 might written to the third disk and so on. A 3 is written to the first disk and 4 to the second disk and again a 1 (the difference between 3 and 4) is written to the third disk. In the event say, that disk one fails, we could work out, by comparing the data on disks 2 and 3 what was originally on disk 1, similarly we can do the same if disk 2 was to fail. In this way it is possible (although with a massive drop in performance) to recreate the entire contents of the missing disk, your system can carry on working and as soon as you replace the disk, the missing data is rebuilt onto it. Loose two disks however, it's game over and you are starting to hope that your backups are all intact!

 

Now before someone jumps in, yes I know that my description is a massive over simplification, the parity calculation is not just the difference between the two blocks of data-it's more like a binary XOR operation-and also my description is actually closer to how RAID-4 works, RAID-5 doesn't have a dedicated parity disk but rather the data and the parity bits are distributed across all of the disks.

 

Anyhow storage-wise, you loose the capacity of one disk (so three 2TB disks in RAID-5 would give 4TB of storage, four disks would give you 6TB and so on; the percentage loss of storage gets less the more disks you have), you can have one (and only one) disk failure without loss of data, but performance is not very good especially on write operations because of the need to calculate the parity information each time and write that as well as the actually data. Read performance is generally ok so this would be fine for say a video library where you are mostly reading data back off of it, however it would not be the best solution for say a database with a lot of transactions going on because it would be hampered by the write speed.

 

So as the OP only has two disks then RAID-5 is out of the question, but schoondoggy makes a good point, if this is a 'production' setup then you really have to have RAID-1 for redundancy otherwise you could try a RAID-0 setup for testing and compare the two performance-wise. As you are using an on-board controller and two very dissimilar disks, I wouldn't expect to see a huge difference in performance but for just 'playing around with' then go for it and see what you get.

 

John

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