RAID 1 decrease perf reading

[Guest]

Hello,
I've got a RAID 1 of two SAMSUNG SpinPoint F3 1To, my motherboard is a GigaByte P67A-UD3P-B3. I use windows 7 x64...
Everything is fine, no problem while setting up the RAID (my first one) and installing the OS, and the RAID windows drivers (Intel Rapid Storage Techonoly). I enabled Write-back cache and initialized the RAIND. This software says that everything is alright...
By when I benchmark my RAID with HD Tach, it says :
Average Read : 119.8MB /s

Here, we can see that se same HD, alone, is better... : 124.8MB/s
http://www.bit-tech.net/hardware/storage/2009/10/06/samsung-spinpoint-f3-1tb-review/3

So... WTF ?!

 

[Wamphryi]

Not all drives are going to perform identically down to the MB per second. Different controllers can play a role. A different OS and Drivers will also play a role. Your 119 MB reading is probably within the range expected for those drives and you will not notice a difference in real world performance.

 

[Guest]

I thought that with 2 HD it would read faster... so it's the fault of the RAID controller (my motherboard) ? Crap...
I'm really disappointed...

 

[Wamphryi]

Ah I see. If you want more throughput you want RAID 0 not RAID 1. RAID 1 mirrors the drives for redundancy. One drive fails the other still has the data. RAID 0 Stripes the disks so that two disks work as one thus in theory doubling their read write speeds. Put them in RAID 0 and you will hit 230 MB a second most likely depending on your controller etc. This also means you get double the capacity. But in the event one drive fails the other drive will not provide redundancy and you have to rebuild the RAID and start again.

 

[Guest]

But I want perf AND security, so i thought that raid 1 double read speed AND data security... raid 0 decrease security...
If I buy a third HD to set up a RAID 5 ? It will increase perf... or not ? As I thought that the raid 1 would increase perf, and it not, I fear the raid 5 to act the same way...

 

[Wamphryi]

RAID 5 can do nasty things to your write performance and generally requires a high end controller to perform at any respectable standard.

This is my advice Dude. Stick with RAID 1. RAID 0 does double performance but not in a way that will make any real world difference to you. Think of it like this.

If you copy files to another drive unless you are writing to a drive that can read as fast as your RAID can write then the drive you are writing too or going the other way around reading from makes a bottleneck. Same thing if you read off a DVD or CD. Most software reads and writes at speeds well under what your current drives can put out.

If you really want drive speed you need SSD. Not for its big throughput but for its reduced seek time. Less seek time translates to speeds that make a difference. RAID 0 does not decrease seek time. Seek time is found in the latency of having mechanical heads reading off spinning platters.

 

[Guest]

Arh, I hoped that I would be able to start up in 40 seconds using a RAID to speed up my HD, but you're right...
So, I will keep my RAID1, but I'm a little disappointed.
Thank you very much.

 

[hang-the-9]

Raid 1 is not the raid you use if you want to speed things up. RAID1 is used for disaster recovery so you can swap out a drive when one fails. It may offer a tiny increase in some disk operations, but nothing you or many benchmarks will even notice.

 

[Wamphryi]

Arh, I hoped that I would be able to start up in 40 seconds using a RAID to speed up my HD, but you're right...
So, I will keep my RAID1, but I'm a little disappointed.
Thank you very much.

Don't let your disappointment rob you of the ability to select the best answer ;-)