Raptor Raid 0 Ups Access Times?

[SKiTLz]

Currently using one 36Gb Raptor as my OS/Apps drive. I have another sitting next too me Im either going to sell or run in Raid 0.

My main focus is a snappy feeling OS and load times. The raid array would obviously help mym game load times but it would also bump the access times would would lose a bit of the "snappyness" wouldn't it?

Just looking for your guys opinions. Theres so many different opinions on Raptors in Raid 0.

 

[Philip]

I can't say on the Rapitors. But on a pair of WD 7200 RPM drives I used to Raid together. It raised the access times from 10mls for a single drive to 15 mls with Raid 0. This was reported by HDtach testing. Threwput only raised from 24 MBS transfer to 34 MBS.

For me Raid 0 wasn't worth the effort. I had one failed drive and three broken stripes in a 6 month period. That was enough. I use other faster drives now.

 

[Ugly_Jim]

For fast load times and snappy OS/apps, you'll enjoy RAID0. The question is "is it worth the money" which is posted all the time. two 36gb raptors will give you around 95mb/s read and write, it's awesome. I think it's worth it for game load times, winrar file splitting, quickpar file recovery, and of course, OS load time.

I think raid0 only adds a couple ms to your overall access time. I don't know how much it is, but it's not double.

 

[SEALTeamSix]

I definitely notice the boost of my RAID 0 array, mostly when I'm dealing with large files like booting into Windows, loading game levels, moving my media files around, etc... there you will see a great speed advantage over one drive - you'll be the first one loaded in game servers, load windows in 2 bars, etc. Also, I haven't seen any decrease in snappiness using RAID 0. Just make sure to back up your sensitives, or keep them on another disk, in case the array goes down, 'cause if it does it ain't coming back up.

-SEAL

 

[SKiTLz]

thanks for the feedback fellas. Going to setup the array latter tonight. Now all I have to decide is what stripe size to use. Im thinking 64 or maybe 128.

Any preferences from folks that have tried both?

 

[tazdevl]

Let's put on our thinking caps and remember we're talking about milliseconds. No one can tell the difference.

RAID 0 is worth it for the reasons mentioned above.

Just be sure to back up your array regularly.

 

[Snugglebear]

Let's put on our thinking caps and remember we're talking about milliseconds. No one can tell the difference.

RAID 0 is worth it for the reasons mentioned above.

Just be sure to back up your array regularly.

The vast majority of humans can perceive a 100ms hang/pause, be it due to software, hardware, or whatever. If systems stored data in contiguous chunks and didn't have to perform dozens, if not hundreds of I/O ops per second, at least a good third of which are going to involve seeks, yeah, nobody would notice. That extra 35-75% boost in access times adds up very quickly into something humans notice. I've been there and done that with RAID0, and there's no way in hell I'm going back to sluggish operation.

 

[SKiTLz]

The vast majority of humans can perceive a 100ms hang/pause, be it due to software, hardware, or whatever. If systems stored data in contiguous chunks and didn't have to perform dozens, if not hundreds of I/O ops per second, at least a good third of which are going to involve seeks, yeah, nobody would notice. That extra 35-75% boost in access times adds up very quickly into something humans notice. I've been there and done that with RAID0, and there's no way in hell I'm going back to sluggish operation.

so your saying Raid 0 was actually more sluggish for you?

 

[Snugglebear]

Yes, it was rather disappointing. Many argue that because RAID0 increases the throughput of the logical drive that your operations get done faster as compared to a single drive, even after you pay the penalty for increased access times. There is truth to this, but only when the data is nice and lined up. My usage patterns involve a lot of multitasking, database work, and file serving. All of those result in lots of I/Os per second to all areas of the disk. I keep my disks defragged and the data as contiguous as possible, but because of how I use the machine, and the applications I primarily use are written, RAID0 provided a significant degradation in performance.

 

[SKiTLz]

ahh.. well that I didn't want to hear...

Im pretty heavy on the multitasking myself. I trreat myy apps like turning lights off, Id rather leave them on incase I come back.

I guess the only way I'll know is to give it a shot. Bit of a long test though...

I'll post back with my impressions if anyones interested...

Cheers

 

[Philip]

I guess the only way I'll know is to give it a shot.

Give it a try. You all ready have the hardware. That is why I played with it. The board supported it and I had the drives. I noticed the same thing as Snugglebear did.

But the one thing I did learn. The computer did like the fast transfer speeds that Raid could provide after the lag was past. At that time I stepped to SCSI. Faster transfer speeds. Not limited to one disk access at a time. True multi tasking. Faster access times. Windows does not slow down when a drive gets full. Less CPU used for disk access. It offloads the commands to the SCSI controller which does the work. Burning a disk takes 5% CPU instead of the 50% plus that IDE uses. (This is with SCSI burners)

I could go on with more. But you need to try Raid for a while to see if it fits your style of computing. If it doesn't. You have the fastest SATA drives on the market. So the next step would be SCSI.

 

[tazdevl]

The vast majority of humans can perceive a 100ms hang/pause, be it due to software, hardware, or whatever. If systems stored data in contiguous chunks and didn't have to perform dozens, if not hundreds of I/O ops per second, at least a good third of which are going to involve seeks, yeah, nobody would notice. That extra 35-75% boost in access times adds up very quickly into something humans notice. I've been there and done that with RAID0, and there's no way in hell I'm going back to sluggish operation.

Little off base here. The difference between RAID 0 and a single drive is ~10ms.

A lot of people read something (like RAID 0 increases latency significantly), try it out and look for something wrong even when they truly can't see it. ATI's filtering is a good example. Short of breaking down the mip-maps in an analyzer, no one can see the difference in a rendered frame.

Other reason why some people have a tough time with RAID 0 is that they just don't have the system to drive things or components don't work well together. The original poster should be fine.

 

[Snugglebear]

Little off base here. The difference between RAID 0 and a single drive is ~10ms.

10ms is more like 80-100% over a single drive. My experience over the years is that single ATA units will generally take ~10-13ms to access any given portion of the disk. Putting them in a RAID0 stripe bumps that up 4-8ms, but it depends on a number of factors, including firmare optimizations, controller drivers, if the disks are spin-synced (ATA cannot), and whether the drives can hold a steady rate of spin if they aren't. The real scary part is that ATA units' access times are getting longer with higher data densities. And lastly, my dabbling with RAID0 was a test to see if ATA could beat SCSI in overall performance; it didn't.

 

[SKiTLz]

Well I just spent the night reformating and setting up my raid array. After using it for sometime while setting everything up again I see what you guys mean. It does feel sluggish in areas. Personally Im not too impressed. Problem is I don't feel like setting up my system all over again. Just got things the way I like em.

So I think I'll tough it out for awhile but Id say I'll be going back to a single drive or scsi next time round.

 

[Philip]

So I think I'll tough it out for awhile

Run it for 6 months or so. Then you will have a good feel for the way it acts. Just a couple of days isn't a good test. I ran it for six months. Then I broke the system down and used the IDE drives in two different computer I was building as xmas gifts. I put SCSI back into mine at that time. At that time a Atlas 2 10k drive blew the WD 7200 RPM drives in Raid 0 out of the water all the way around. I have used SCSI ever sence.

The computer I was on at the time was a P3- 933. It felt like a different machine with SCSI in it. No more lags or waiting to do something. My girl has that computer at college right now. The few people that has been on it could not belive it was a 933 by the way it acted. It now uses a IBM 15k drive. I use the old Atlas 2 on this computer for Win98 as a backup OS in case my XP-Pro dies.

 

[Snugglebear]

The computer I was on at the time was a P3- 933. It felt like a different machine with SCSI in it. No more lags or waiting to do something. My girl has that computer at college right now. The few people that has been on it could not belive it was a 933 by the way it acted. It now uses a IBM 15k drive. I use the old Atlas 2 on this computer for Win98 as a backup OS in case my XP-Pro dies.

The disk is the slowest subsystem in the computer. An upgrade to SCSI is about as much as you can do for a given system. But then a faster ATA unit can help, too. That's the first thing I do to non-techie friends & family who want to make those old desktops last a little longer. Of course reinstalling windows doesn't hurt either, but the faster disk really boosts things.