RAID 0 for Video Capture (Drive Question)

[sbain]

I am new to RAID and am setting up a new deck on a P4PE platform and want to use the system for video capture off digital TV... I intend to use full 720x480 resolution w/ full frame-rate... I will have both a 9700 AIW and Canopus ADVC-100 in the system and intend to capture through both.

I decided to setup a RAID-0 to avoid any dropped frames. I was origially going to setup the system with a 80 GB System Drive and 2XWD 120s with 8MB buffers. Long question short, am I going overboard on the RAID in terms of the drives I am using? Should I get a bigger system drive with a buffer (as this is probably where I will archive/playback my captured video) and smaller RAID drives without buffers.

Any thoughts?

[VideoTechMan]

Here is my suggestion/opinion:

While RAID is good for captruing video, it's also more tricky to configure as well, especially if you run into problems down the line. You can do just fine getting a 80GB hard drive but make sure the rpm speed is 7200. Anything lower and you may have frame dropping problems. Also with a fast system, you shouldnt have any problems capturing DV or whatever kind of footage you plan to capture. My system I have 2 80GB hard drives, both 7200RPM, and it doesnt matter too much on whether you have the 8MB cache or not, both will capture fine without dropping frames. In addition, I have found that in Win XP, you can change the hard drive's properties and set it to compress files to save space. When i did this, I tested the drive's read/write speeds using the Canopus EZDVtest (you can find this tool on the Canopus Web Site) and both drives came out at 80MB/sec for write, and about 800MB/sec for Read. I was blown away when I saw those figures, and when I did a test capture of a 20min clip in Premeire, it did not drop a single frame. With the drive writing at 80MB/sec, there's really no way you can ever drop frames, since most captring/editing programs require at least 4MB sustained throughput (DV has a set fixed capture rate at 3.6MB/sec, analog capture can vary). I would recommend just going with the IDE hard drives. What is your computer's configuration?

VideoTechMan

[sbain]

Not too sure yet... Still formulating but, other than the hard drives, it should be about as follows:

Asus P4PE i845PE Mobo
Kingston 2700s (2 512K sticks)
Pentium 2.66 or 2.8 GHz Processor... possibly the 3.06 if it comes down in price with this new 3.0 G 800FSB processor Intel just put out.
XP Home Ed.
A-105 DVD-RW
AIW 9700 Pro

[VideoTechMan]

Based on the configuration you gave, going with IDE drives will work excellent for that system. I only have a 2.4GHz Pentium 4, but it does the job just as well. You shouldnt have any problem capturing to IDE drives.....processor speed only comes into play when you are rendering or encoding.....capturing is pretty much straightforward and pretty much relies on the hard drive's speed. If my guess is correct, your motherboard's built in IDE controllers should support ATA100/133. Just be sure to put both hard drives on the same IDE cable (for example both hard drives on IDE 1 and both of the DVD drives on IDE 2). Since the interface of the DVD drives are about ATA/33 or 66, that can be a problem when you have a HD connected with the dvd drive.

VideoTechMan

[sbain]

I do know that the board has Promise PDC20376 SATA 150 RAID on board... As such, I will have to by SATA>ATA/IDE conversion cables (30 bucks or so)... But, by definition, I think that means I will be on a seperate channel... is this right?

[VideoTechMan]

Yes, it will be on a seperate channel. SerialATA is realitively a new technology, which I am sure it's good. But to down convert to the normal ATA, it will perform just as well. I dont have SerialATA...my motherboard doesnt have it, but i dont know much about it yet to really give a good analysis. But in the meantime, the current ATA speeds will work just as well.

VideoTechMan

[sbain]

PS... the southbridge would be 82801DB.

[txpharoah]

sbain, I use a HD setup just like that at work with a Matrox. It's great.

[disturbed1]

and both drives came out at 80MB/sec for write, and about 800MB/sec for Read.

That's due to buffering.

Use Virtual Dub's auxsetup utility to run a sustained read/write test with a file size greater than 1gig. With short read/writes it claims I have a read rate of over 1gig/sec, which is no where close to truth.

720x480 29.97fps YUY2 uncompressed with 48khz 16 bit stereo audio runs around 20mb/sec. Most 7200rpm ATA 100 drives can handle this. Throughput across my non raid drives is 29-33mb/sec sustained, depending on which cylinder is being written to. All of my drives are either Maxtor or Seagate 7200rpm 2mb buffer ata 100, with cooling fans.

Your JB Western's would be able to handle the capture chores in a non raid setup. I'd keep the three seperate drives all in master, system drive on the MB's IDE controller, and each WD as master on a seperate channel on your raid card. This will vastly increase compile and multiplex times. Most apps that I use take advantage of multiple scratch drives which would yeild higher performance than a simple 2 drive raid 0 config.

In a single computer that captures, edits, and authors, a single ide raid setup isn't ideal, because you take a huge speed hit during same time read and write chores (multiplexing, running pulldown, compling a dvd etc.)

If you have the bucks, use 5 drives, 1 system, 2 as raid 0, then 2 more in another raid 0 array. That would blister.

[sbain]

I am sorry but what you have said in this last post is completely over my head (new to RAID).

However, it sounds like you have a different spin on things. Assuming I cannot afford to get 5 HDs right now, what are you saying I should do with the 3 I can afford? It seems you suggested I don't RAID 0 the two for capture. I should be clear that I probably won't be working so intensely on this as to be trying to capture and re-encode raw video at the same time. Also, why would I want them all as master and none as slave?


All I want to do is cature (and leave my computer alone while it does this) followed by an overnight conversion and, finally, a write to DVD the next day.

In the context of this, if you could explain what you were saying in laymans terms I would really appreciate it.

Thanks, again, so much for any feedback you can offer.

[sbain]

Sorry for the multi-posts but I also have one more question. Do I need cooling on my hard drives?

[disturbed1]

RAID 0 is great when you only read from the array, or only write to it.

IDE has a flaw that doesn't allow fast enough transfers during same time read and write. Think of trying to copy a CD from your reader to your burner while they're on the same channel.

When you compile a DVD you will be reading and writing at the same time to the same drives. In that case Raid 0 is slower than a multi drive set up.
Editting uncompressed video is also slower on a simple 2 drive RAID 0, than on a JOBD setup.

Capturing will be fine, because you only write to the drives at that time.

If you plan on capping for extended time periods, cool your drives, they do get hot after a while.

[coda304]

disturbed1

You left out the fact that to run a system with 5 hard drive(s) + efficient cooling you will need at least a 400-500 watt rock solid Power Supply! Don’t go with an el-cheapo PS either, they often are over rated, here some companies to avoid from the top of my head Antech, AGE, CompUSA brand. A rock solid choice would be anything from PC Power & Cooling or something recommended from AMD/Intel’s system builders web site(s).

[jennyandgreg]

So if I am following correctly a solid system would have one drive for the operating system and general software, one drive for the raw video footage, and one drive for the compiled video. This would eliminate any drive having to read/write at the same time.

Is my logic correct?

[scott@butlerandco.co]

Can someone explain why you would use raid level 0 and not 5. If you are looking for the most performance and drive space for the future you get more out of raid level 5 and all i read about is level 0 which is disk duplication ?

Thanks
Scott

[disturbed1]

So if I am following correctly a solid system would have one drive for the operating system and general software, one drive for the raw video footage, and one drive for the compiled video. This would eliminate any drive having to read/write at the same time.

Is my logic correct?

You won a cookie.

I've found that, that setup is best for pro-sumer work. With each drive opperating in master on it's own channel.

Can someone explain why you would use raid level 0 and not 5. If you are looking for the most performance and drive space for the future you get more out of raid level 5 and all i read about is level 0 which is disk duplication ?

Thanks
Scott

Raid 5 doesn't offer any speed over Raid 0. Only fault tollerance. Raid 5 is good if your worried about data loss.

Raid 5 uses 3 drives, 2 mirrored (Raid 0) and 1 for parity blocks.

Read transaction is slightly increased, with write transactions decreased because of the need to write the same data twice.

http://www.acnc.com/04_01_00.html good raid info.