Velociraptor and RAID

[dark strike1]

I just recently purchased a 300GB velociraptor and I am trying to RAID it with two regular 150GB raptors. But when I create the array it only shows up as being a 300GB Raid 5 Array??? It should be 600, or 450 due to one drive being the parody drive in a sense. Whats going on?

 

[Baez]

It's parity not parody. Did you set it up as a RAID5 array? Also is it a hardware or software RAID? If you attempted a RAID0 it would end up as 300GB although it wouldn't even work.

 

[kmote]

It's coming out with the correct size since 150GB of your 300Gb are being wasted leaving you 150GB * 3 of which 150GB is going to parity.

EDIT: Baez, as RAID 0 it would work - he would still drop 150GB from the 300GB but it would still come out as 450GB.

 

[office politics]

disks should be the same size. although some controllers may use the size of the smallest disk. the size of the logical unit should be the combined total minus the siaze of one disk

 

[dark strike1]

Okay so I have:

1. Raptor 150GB HDD
2. Raptor 150GB HDD
3. Velociraptor 300GB HDD.

So it is coming out correctly as a riad 5 array of 300GB? Why is 150GB of my veloci being "wasted"?

 

[kmote]

As long as that's ~300GB of usable space, yes.

 

[Baez]

EDIT: Baez, as RAID 0 it would work - he would still drop 150GB from the 300GB but it would still come out as 450GB.

I was saying software wouldn't work in RAID 0 I just didn't say it properly.

 

[kmote]

Fair enough. Software RAID 0 doesn't make sense anyway so I hope he isn't trying that.

 

[Hefemeister]

Okay so I have:

1. Raptor 150GB HDD
2. Raptor 150GB HDD
3. Velociraptor 300GB HDD.

So it is coming out correctly as a riad 5 array of 300GB? Why is 150GB of my veloci being "wasted"?

Think of it like RAM. when you use 2 sticks of different speeds your RAM can only run at the speed of your slowest stick. In your case you need 3 drives of the same size for raid5. Since 150gb is the smallest size that it the size all 3 drives will be treated as. So a raid5 of 3 150gb drives = 300gb. You may want to consider a different setup. What are you hoping to accomplish with this raid array?

On a side note make sure you have some cooling for all of those raptors. They run hot. I have a striped array of 2 raptors (for OS and programs, no important data) and they definitely heat up my case. I have a 110mm fan pulling air over them to keep them cool.

 

[dark strike1]

Ah ok that makes total sense. The thing that was throwing me off was the part where the drives had to be the same size. I forgot Raid 5 needed the same size drives in the raid otherwise it would waste any extra space. Alright that cleared it up for me. Thanks guys.