confused about raid

[ak48]

I'm confused about using raid with audio files.I'm told that it is best to store program files on on hard drive and audio files on another.Using a raid controller the audio files will be split on both hard drives and what if I want to store video files as well?
Can some pro please enlighten my limited know-how
of PC's
Tar
Tep

 

[jscott]

Originally posted by ak48:
I'm confused about using raid with audio files.I'm told that it is best to store program files on on hard drive and audio files on another.Using a raid controller the audio files will be split on both hard drives and what if I want to store video files as well?
Can some pro please enlighten my limited know-how
of PC's
Tar
Tep

Much of your answer depends upon your motherboard and RAID controller. For example, yes, 2 drives can make up the array, which means two or more drives share information as would be the case with one IDE drive. However, depending upon the controller, and or mobo, you can also run another arry as a "second disk", or, still use a IDE single drive as another disk, or for that mater, several cobinations thereof, upto maybe 4 to 5 assigned drives. Suchas two on the IDE controller as Masters for each channel, and 2 to 4 on the RAID controller as either IDE or arrays.

But don't think of RAID as the solution to all the problems, because it won't do a thing to lower Latency if the interface and drivers are of a poor design. RAID just helps you get the stuff to and from the disk faster, it doesn't speed a slow interface.

RAID 0 can be comprised of up to 4 drives with these MB's. In theory, when using 2 drives, you can read and write data at about twice the speed of the slowest drive. With 4 drives, you can get about 3 times the speed of the slowest drive. So you could save some bucks buy adding 5400 rpm drives, but capacity is limited to the smallest of the drives times the number of drives. RAID 0 is very volitale to loss of data.

With RAID 1, this is a true mirror, and is therefore redundant, however, the writes are equal to the slowest drive whereas the reads are twice as fast as the slowest drive. RAID 1 requires even pairs of drives and capacity is equal to the smallest of drives.

In both cases, the reads will out perform a simple drive. BUT, If you put everything on one RAID group, the heads have to move between program calls and data reads thereby slowing down the function of your only drive group.

The best of both worlds is one raid 0 array and 1 RAID 1 array. In my opinion, you use Raid 1 for apps and data back up, and RAID 0 for cutting the tracks. You just need good dicipline for backup routines.

 

[teddancin]

-jscott

Yeah, but those speeds are In Theory. I want to add that the ONLY way I got decent transfer speeds with RAID0 (striped) was by running the RAID through my OS's RAID setup, which you could do with your regular IDE channels on a non-raid motherboard. The problem with this is that not only do winME and older OS's not support it, but it also eats up your CPU usage because it's maintaining the RAID array through your OS, and not through a hardware configuration like it should. Just some stuff to think about before you dump your money into raid. I'm all about benchmarks and bottome lines, and IDE RAID (the controller cards and on-board channels I could afford anyway) just didn't cut it.

 

[Opus2000]

Well, here's my take on it since I am just a newbie on RAID setups myself!
This is how I am setting up my system to see what bench marks I get..
Primary Controller on mainboard gets the OS and app drive as Master all by itself...
Secondary Controller on mainboard gets CDR/W as Master all by itself.
Two Maxtor 40GB drives on the ATA 100 RAID controller card set as RAID0(Striped) I will be adding two more drives to get the RAID 0+1 setup eventually but for now I am just doing the RAID 0.
Right now I'm seeing that XP handles this much better than Win2k for some reason. I'm seeing a better throughput in the long run.
Unfortunately I havent gotten to the point where I can give you solid benchmarks..keep getting distracted from my work!! lol
Opus

 

[jscott]

Originally posted by teddancin:
-jscott

Yeah, but those speeds are In Theory. I want to add that the ONLY way I got decent transfer speeds with RAID0 (striped) was by running the RAID through my OS's RAID setup, which you could do with your regular IDE channels on a non-raid motherboard. The problem with this is that not only do winME and older OS's not support it, but it also eats up your CPU usage because it's maintaining the RAID array through your OS, and not through a hardware configuration like it should. Just some stuff to think about before you dump your money into raid. I'm all about benchmarks and bottome lines, and IDE RAID (the controller cards and on-board channels I could afford anyway) just didn't cut it.

Teddancin - I absolutley agree with you. As I said

RAID 0 can be comprised of up to 4 drives with these MB's. In theory, when using 2 drives, you can read and write data at about twice the speed of the slowest drive....

He wanted to better understand the concept. Adn you are right to stress the theory part.

We're in agreement. But that's the concept behind it. I don't think most project studio users ever even need to consider the tech spec boxes being built. Clearly for most, only two drives need be considered on the IDE channels. And I would also agree that a off-board RAID controller may give better performance than an on-board one for the reasons you state.

In his case, maybe a RAID mobo does make even more sense. But not for RAID. Just the added channels. This way he could isolate the video, audio, and apps.

I want to be clear though. I'm not a video guy, so I could be way off base for a video config.

 

[Opus2000]

I would think by having four drives, on two RAID 0 setups would do the trick. One stripe for audio and one stripe for video...now, the fact about losing drives is one chance you have to take over performance. Video pull is a hell of a lot more intensive than audio so you wont want the video and audio data being pulled from the same disk...
Choosing a RAID setup can be hard especially with video in mind. One option to go for is two RAID cards or an ATA raid and a SCSI system as well...SCSI would be ideal for video.
Opus