View Full Version : Raid-0 vs Raptor
06-27-2008, 08:34 AM
Alright, I got anthor this or that question, this time its just for your own personal perferance. The question is.....
We all know how Raid works, how its basically 2-6HDD working in tandam with each other, Raid-0 being data shared amoung all HDD on the array, and Raid-1 being a mirror of said data amoung all HDD on said array.
Basically I have 2 HDD in Raid-0, they are 7200RPM drives with a 8.2ms Seek time and 16MB cache, the Raptor on the other hand has a seek time of 4.2ms, and a 16mb cache. I got the 2 7200drives becuase I thought it is faster than a single Raptor, cheaper, and has alot more space (150GB vs 640GB!). If Raid is set up proberly (which I hope it is) I should have a seek time of 4.1ms, and a 32mb Cache! On top of that both my HDD run at full load 37C! This is mostley due to the 12cm fan blowing cold air directly on them, but still.
Now I saved about $40 on my set up vs a single 150GB raptor, well worth the trouble of setting up RAID, or do you think the raptor still out performs 2x 7200RPM drives in RAID-0?
07-05-2008, 08:15 AM
I'm about to set up a RAID 0 on my rig for running my OS and games, but I'll have to question your difference in seek times. Your seek times will not change with the RAID 0--only your data transfer ability. The drives must still seek at their original speeds, because the heads only move so fast. Correct me if I'm wrong. I really don't know how fast those Raptors work, since I don't own one. I'd really rather just wait until the FDDs get up to speed and fully utilize the SATA II 3.0 interface. Hard to beat .001ms seek times... But that's just me being cheap. I happen to have extra HDDs sitting around, and when I'm bored, I tinker--hence the RAID 0 setup. Plus, I love pushing my system.
07-05-2008, 07:14 PM
I believe the seek times are cut in half with 2 drives and that cut in half with 4 drives, becuase if you think about it, its 2 hard drives looking for the requested information at the same time. Basically 1 hard drives has to only find half the info, and the other drive the same. That lowered data load can be requested,and carried out faster. Its kinda hard to explain. And I've never owned a RAPTOR drive, i think there a waste of money, hardly any space, too much heat, and they arn't reliable from what I hear. What i would like to get my hands on is one of those fancy LARGE flash drives, they last forever, have almost no heat, and have phenomal seek times, but there SMALL, like 16GB for the cheapest one.
07-05-2008, 08:05 PM
Unfortunately, it's not that simple. It has to do with stripe size and what particular application you are utilizing the RAID setup for. For example, when you are copying a large file that exceeds the stripe size, both drives will be working in the same place accessing the data and performing I/O. In this particular application, you see no gain in latency/seek times. You do see the transfer speeds double (which is the main gain in RAID 0).
However, in accessing data across the drives that is smaller than the striping block, seek times will be cut in half (in a perfect setup with data evenly split) or better depending on the number of drives. Database access is a good example of this.
Since most gaming applications nowadays include loading massive texture files into RAM, you will see performance gains that are more moderate, rather than double/triple. For this reason, I'd think that a Raptor would provide better performance, since the gains are seen across the board. For me, a Raptor just isn't cost effective, as I'd have to have several of them to keep all of my installed games on them ( have over 430GB on one drive).
By the way, RAID controller ability and CPU usage of RAID controller can provide a bottleneck as the RAID size increases. Another small factor is disk cache size, as in simple application use (depending on the OS), seek times can be dramatically reduced as the disk cache size compounds. In a 6 drive setup with 32MB cache/disk, 192MB of your applications reside in the cache, which can REALLY make a difference. Most people don't have that kind of setup, though.
So basically, striping size and data spread determine performance in a RAID 0 setup. Personally, I like the idea of improved data transfer rate, and this is enough to push me into a RAID setup. I spend a lot of time transferring large files from drive to drive, so that would be optimal for me.
07-05-2008, 08:12 PM
Just an FYI if raptors are too small for you they have some VelociRaptors out there now. They are still 10,000 RPM but have 300GB instead of the 150GB.
07-05-2008, 08:39 PM
Thanks, man--unfortunately they also cost a good crisp $300. $1/GB? noper.
07-05-2008, 08:40 PM
Yeah I know what you mean unfortunately they are pretty expensive. But they are there! :p
07-06-2008, 05:42 AM
I'll keep with 2 drives in RAID-0 thank you, I think its better since the performace is incresed from a single 7200PM drive, as well as massive amout of data storage, with less heat than the raptor. It may not be as fast as a raptor on most applications, but there is an improvement like I said.
07-06-2008, 05:46 AM
It is for those very reasons that I will enjoy my dual 500GB WD 7200rpm 32MB cache RAID 0 setup this coming week when I get it set up.
I'd rather that then spending extra dough.
Seek times stay the same. Data transfer rate changes, but the drives are still moving at the same speed.
07-12-2008, 08:38 AM
As I said--not always. You seem to misunderstand how the data is stored/accessed. Yes, they spin the same speed, but read the above posts.
Sunny, dude, your system is absolutely beastly. If my wife would let me, I'd have a rig identical to yours. (I'm doing it over time so she doesn't notice).
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