RAID0 and Defraging in WIN2k

[HJL]

Hi.
I have RAID0 in win2k with 2x DTLA307030s.
When I analyze the disk using the defragmenter that came with win2k, the graphic analysis shows me 2 big chunks of data. The two big chunk probably represent the separate disk, but if I defrag it, will all the data move to one disk only?

If those two chunks combines, would that mean the data moved to one disk more than the other and therefore makes RAID0 ineffective?

Thanks.
The RAID performance is ok I guess. I get about 60+mb/s where as I was getting around 26mb/s with one disc.

 

[Zach]

I'm sure it will be fine.. we could ask and clarify if you have Win2K's software raid, IDE RAID, or SCSI RAID (forgive me for not knowing HD model numbers), but either way go for it. If you are using software RAID and Win2K manages to foobar it with it's defrag, you shouldn't use it anyway.. and anything beyond the OS should not be detectable to the OS as anything but two hard disks..

 

[Calum]

Hi,
I have a modified A7V with two 30gig ibm GXP 75 (like yours, I think). Your RAID array appears to be working OK, given your speed readings That being so, the OS (including any defrag utilities) should see the two drives as one single volume, and defragment it as such. I have used O&O and Diskeeper on my 60Gb RAID0 array with no probs whatsoever (the Win2k built in defrag program is just "Diskeeper Lite&quot

Hope this helps,

Calum

 

[HJL]

I'm using 2 IDE Drives using AMI MegaRAID.

There is nothing wrong with my RAID setting, everything works fine. and win2k sees the drive as a single C drive.

My question was to ask if the defraging will move data from one drive to the other more.

Anyway, thanks for your inputs guys.

 

[potz]

No it will not move data from one drive to the other. Half of your data is stored on one drive and the other half on the other. For example, 1 byte is made of 8 bits. So in Raid0, bits 1,3,5,7 will be stored on drive 1 and bits 2,4,6,8 will be stored on drive2.

 

[Calum]

Sorry HJL, I misunderstood your original post. It is inherent in the way RAID 0 works (as far as I understand it, anyway), that the data is split over the two (or more) drives equally. If the data could be "skewed" towards one disk or the other, then you'd lose the speed benefit of the two drives running in parallel. The defrag program sees the two physical drives as one logical drive, and so there is no mechanism by which it can move the data from one disk to another. It defrags the data within the context of the single volume maintained by the RAID controller.

Perhaps the two chunks you see in your defrag program are the MFT and the data on the drive itself?

Hope this helps,

Calum