SATA II Raid 0

[Super Chocolate Bear]

OK what I want to do is get 2 or more 200/250/300GB Seagate Drives and put them into a raid 0 array.

From what I understand if 1 drive transfers at around 50Mb/s

then these should be close to the speeds I should get.

2 x 300GB in Raid 0 = roughly 100mb/s
4 x 300GB in Raid 0 = roughly 200mb/s

Is this correct if not what could I expect.

Is there anyone who has actually worked with Raid 0 setups recently? how does it perform?


Thanks guys

BTW I know Raid 0's risks but by using Seagate drives I should be fine. Have not had a single problem since I started using computers. Seagate = Best in da world.

[sss]

well i wouldnt go as far as 2x improvement for having 2 drives!

i think you get around a 40% increase with 2 drives in raid compared to 1

now the trick thing is how do you install this?

my windows raid software told me it had to be installed in windows... but then how the crap do you install the os onto the drive first!!!!

[stoke]

Wooooha !
Do not use windows raid ... ever.
Well .. not for speed anyways.

Your motherboard must support RAID and you must use the motherboard facilities to setup the RAID BEFORE you install the OS.

I found 8% improvement on BF2 loading times. Not mutch, but the redundancy aspect is my real reason for doing it.

[Bass]

Ummm - if you got any speed improvement you are most likely using Raid 0, which has no redundancy. Of course if you used RAID 0+1 or 5 (if your board supports it) then you would get a performance increase.

Would also go with about a 50% performance gain for 1 added drive.

As Stoke says - don't use windoze raid !!! - must be hardware to be of any use. Preferably go for a RAID controller with it's own onboard RAM for best results ...

[stoke]

me was talking about RAID I ... mirror.
Your reads are twice as fast but yer writes are a the same speed as only one disk.
But in truth the reads were not twice as fast unless the bottleneck i'm experiencing with BF2 is processor related.

[TG]

I once had a raid 0 stripe going using my mobo's on-board promise raid controller. 2x 100gb drives. The mobo blew. Lost 200gb of data (Yeah yeah, screw backups). I couldn't find a compatible mobo or add-in card to attempt recovering my array.

[Bass]

Ummm .... nope again Stoke

Reads are not twice as fast !

.. taken from http://www.pcguide.com/ref/hdd/perf/...eLevel1-c.html

Degradation and Rebuilding: Slight degradation of read performance; write performance will actually improve. Rebuilding is relatively fast.

Random Read Performance: Good. Better than a single drive but worse than many other RAID levels.

Random Write Performance: Good. Worse than a single drive, but better than many other RAID levels. :^)

Sequential Read Performance: Fair; about the same as a single drive.

Sequential Write Performance: Good; again, better than many other RAID levels.

However this article
http://arstechnica.com/paedia/r/raid-2.html
has this to say:

Now here's an oddity: a read transaction can theoretically occur twice as fast as on single disk. Hence RAID 1 is often used on low-end web servers. The read performance is standard, if not better than single disk performance, and the poorer write performance is largely irrelevant on most web servers (save those doing transactions, of course). RAID 1 configs are great for mid-volume FTP servers as well.

Basically you will only get improved read performance if the RAID controller is clever enough to figure out that it can read eg. half the file from one disk, and the other half from the other one. In practice with onboard RAID controllers you won't get much improvement.

A separate (non-inexpensive) RAID controller is probably the only way you'll really see much improvement ...

Another Edit: See this link for some nice graphs:
http://techreport.com/reviews/2004q2...d/index.x?pg=3

[sss]

lol


well i wanna setup raid... my mobo has it.. i'm going 4 x 300 gigs... 1.2 terrabytes... just for the novelty!

[NerdBoyZa]

Does your board support 4 devices on the onboard SATA RAID? Don't forget that SATA is not like SCSI - you can't just add drives in a chain, until you feel like stopping.

I've only seen onboard SATA RAID that supports 2 drives, but I'm not saying you can't get one with 4 x drive support - just check you can first.

As Bass said as well, with onboard RAID, don't expect too much of a performance improvement. They don't usually have a good enough controller, and not enough onboard RAM either.

Problem with the Add-On RAID cards that are worth it, (my experience here is with the SCSI type), is that for a decent card you are going to end up paying a couple of grand. Not sure it's worth it for the 10-20% read performance improvement.

[Scooby_Doo16]

Prob cheaper to just get raptor/s?