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RAID 0 questions for HD capture

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  • NAS / RAID
  • Storage
Last response: in Storage
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May 21, 2009 2:49:38 AM

I resently bought a Black Magic Intensity Pro card to capture HDMI sources at native 1080p res. My issue now is disk write speed for capturing in RAW format. They recommend the following speed for what I' trying to capture - 140 MB per/sec for 720p and 158 MB per/sec for 1080p. Right now I'm running only one drive at about 55 MB per/sec. I want to increase my storage space for the files as well as speed up my write speed.



I'm new to RAID and all its fun. I have dealt with RAID 1 type setup's in servers but only in passing. From what I understand for my needs I would be wanting to run RAID 0? Is this correct?



I want to try and run the RAID if possible with my current hardware. I'm planning on cleaning off my drives and starting fresh with Vista Ultimate 64bit if its possible to run the RAID with it. If not I will go with XP if I have to.


Hardware and OS as follows

Mobo - MSI P45 Platinum
CPU - Intel Duo E8400
HDD - Seagate 500gb 3.0gb/s SATA
GPU - MSI Geforce 8800Gt Oc'ed
RAM - Corsair DDR2 1066 2gigx2
OS - Dual boot XP 64 and Vista Premium 64 bit
Capture Card - Black Magic Intensity Pro



I'm new to this game so any help with drives to look into, controllers that I might need and any tips, tricks and install help would be great!


Thanks,
Snipethewolf

More about : raid questions capture

a b G Storage
May 21, 2009 7:12:45 AM

You can consult TH's 2009 Storage Benchmarks and see which drive(s) may provide your desired performance.
a b G Storage
May 21, 2009 1:12:26 PM

Quick and short......
Your board supports RAID.
You want 2 identical drives.
It is pretty easy to set up.
Plug drives in.
Enter BIOS set controller to RAID.
Check to see if you have other RAID options, such as RAID as storage, RAID as bootable.
Put the RAID in the boot order if you are using them as boot drives.
Reboot, you should now see a line during POST that says something like "to enter RAID BIOS hit F4" or something like that.
Enter RAID BIOS, set type of array you want, the drives you want to use, build array.
Insert Windows DVD, reboot and start the install.
Vista SHOULD have the drivers.
If all is set up correctly, and had you had 2 500 gig drives, Vista should find 1 drive with 980~90 some odd gig of free space.
If you have any questions or problems, just come back and ask.
Related resources
May 21, 2009 3:09:20 PM

Ok, I have used the guide to find a drive that in RAID should give me the write speed needed. I'm wandering now is it going to help with performance if I install the OS on its own drive or is it best to just RAID all the drives as one?

I will be using the system from some gaming and have read some issues with RAID and games running with random lag.

So OS have its own drive? or just RAID it all?
May 22, 2009 5:29:04 AM

As jitpublisher said, check the charts. However, before proceeding, consider:

1. How much data are you planning on capturing? 140MBs = 8.4GB/min = 504GB/hr.

2. You need to determine the sustained disk serial transfer rate (STR) and ensure that it can keep up--not simply the quoted maximum STR. That depends on the amount of space you'll be using, and where on the drive you're writing...

3. STR varies depending on where you are on the disk; outer-zone STR is typically about twice the inner zone. (The max figures you see are typically outer-zone.) STR doesn't scale linearly across the disk, but if you don't have exact numbers to work with, it's close enough...

4. Rule of thumb: STR = max-STR * (1 - percent-used/2). E.g., write max-STR of 120MBs and you use 50% of the disk during a capture = 120MBs * (1 - .5/2) = 120MBs * (1 - .25) = 120MBs * .75 = 90MBs STR at the end of the capture. That is, you'll get ~90MBs STR when you're writing about 1/2 way into the disk.

5. Given (4), how fast a disk, or how many RAID-0 disks, do you need to maintain a 140MBs STR? That's harder to answer. It depends on individual drive performance, and performance scaling with of the RAID controller, which tends to decrease with an increasing number of drives. E.g., RAID-0 going from 1 to 2 drives might get you an 80% STR improvement, wherease going from 2 to 3 drives might only get you an additional 40% improvement.

In short, you might get away with 2 large drives RAID-0 (assuming you aren't filling them). If using smaller drives, you may need 3-4. Depends on how much of the array capacity you use for a capture, STR of the drives, and how well the controller scales.

I'd put the OS and everything else on a separate drive unless and until you run tests to ensure you have plenty of headroom above and beyond what you need for video capture. (Even a nominal amount of other activity can seriously degrade STR.)
!