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View Full Version : What kind of RAID (5 or 10) setup for a compositing workstation?


kobeone
01-30-2008, 02:40 PM
I have a quick and hopefully easy question. Relativity soon, I will be building a computer to handle my growing demands in the area of HD video editing and HD video compositing. My requirements are a system that can handle multiple streams of HD video. I have done some research and discovered that in order to meet this demand I will need a fast HDD setup (RAID) to do real-time video editing. I narrowed my configuration down to RAID 5 or RAID 10 (1+0 or 0+1) (I know itís expensive but Iím looking for performance with this system) but I canít figure out what would be the best setup. Iíve never configured a RAID setup before so I donít know what would be the best solution. I understand the difference between the two RAID (RAID 10 being faster) setups on paper but in a real world setup will the performance really be that much of a difference?


HDD Configuration
OS + Apps on one 74GB 10000 RPM SATA Drive
Data Drive on four 7200 RPM SATA drives in a RAID 5 or RAID 10


If anyone can think of any better setup then this one feel free to add it. Iím open to whatever can give me the best performance for my compositing work. Any feedback is greatly appreciated. (FYI, I did some searching on the forums and found a few posts but nothing that really answered my question)

imashination
01-30-2008, 03:34 PM
Just a small warning, do NOT use RAID 5 with an onboard controller, the resulting drives will be slower than a single drive will. Your best bet is to get a dedicated controller card, there is a quite significant difference in speed between the $1 chips used on a motherboard and a specific pci card.

aglick
01-30-2008, 03:43 PM
I'll see if I can provide you some direction here.

First, you need to figure out how much disc bandwidth you need. Are you working with uncompressed or compressed HD media?

For compositing, there is no real "requirement" for disc array bandwidth, but the rule is - the more drives - the better your interactivity working with heavy comps.

Are you wanting to do multi-layer video editing with realtime dissolves, PIPs, DVE's etc?
Uncompressed HD capture? These requirements demand more drives in the array - especially if working with uncompressed HD or 2K media.


Next, decide what level of RAID (Redundant Array of Inexpensive Discs) you really need.

If you are just going for speed -and don't mind re-capturing (or re-importing media from your backup) in case of disc failure, then a good old fashioned RAID0 "stripe set" would be the most cost-effective solution. This gets you the best performance for the least $$$, but no fault tolerance or redundancy in case of a drive failure.

RAID10 (a mirrored stripe set) provides fast performance & seamless failover -if one array breaks, the "mirror array" keeps on going like nothing even happened. This is great but requires you to buy TWO sets of drives - one "mirroring" the other but not providing any speed or storage capacity benefit. This is the most expensive option.

This is necessary for "mission critical" or "enterprise" applications, but practically unheard of for digital media production applications.

The best combination of speed and fault tolerance for our industry is typically RAID5. RAID5 is a stripe set which also contains the "parity" information that can be used to "rebuild" the data in case of needing to replace a failed hard drive. It's a little slower than RAID0 and yeilds less useable storage, but if your functional requirments include "fault tolerance", this may be a good option.

**RAID5 volumes can (and will) take hours or days to "rebuild" the data after a disc has failed and been replaced. It's not a simple matter of "just replace a drive and keep on going..." just a heads-up...



Adam
BOXXlabs

kobeone
01-30-2008, 04:48 PM
Just a small warning, do NOT use RAID 5 with an onboard controller, the resulting drives will be slower than a single drive will. Your best bet is to get a dedicated controller card, there is a quite significant difference in speed between the $1 chips used on a motherboard and a specific pci card.

Thanks, Iíll be sure to get a card with dedicated ram on it for my RAID array.



Adam, thank you for all the great information. It is very helpful. Let me answer some of your questions. First, I will be working with a mixture of uncompressed and compressed HD media. The ratio of usage will be 80/20 with compressed HD media taking the lead. I can easily see that ratio changing as time passes. Yes, I will be doing HD capture (uncompressed and compressed) via a Blackmagic Intensity card.

In regards to RAID, I am very concerned about RAID0. If one of my drives should fail then there go my whole array and all my data. I canít take that kind of risk. I know that RAID10 is a little overkill but it seems like a happy medium. You stated that RAID5 is the ďbest combination of speed and fault tolerance for our industryĒ. Under this configuration will I still get speedy interactivity when working with heavy HD comps? Specifically uncompressed HD comps? Every article I have read said RAID5 is slow is on write speed. With all my project files and video being stored on this RAID array Iím concerned that the lack of fast write speed will cause a huge bottleneck when writing my files. Once again I have no experience with RAID5 performance so this could be all in my head. Thank you for the heads up on information on the rebuilding process.

aglick
01-30-2008, 05:37 PM
For stable RAID5 writes at uncompressed 10-bit 1080/60i datarates you will need 8 (eight) of the newest perpendicular SATA drives and an ATTO R348 RAID controller.

This setup will cost you about $2200 US street price and is frankly the "entry level" solution for getting enough RAID5 write performance to capture uncompressed 10-bit HD to sequential frames such as DPX, tiff or targa.

(if you are only going to be capturing to "encapsulated" files such as AVI or QT, you could probably get away with only 6 or 7 drives in the array)

This same setup is fine for most compositing work, although heavy comps can always use more drives to speed up loading of frames when scrubbing or advancing through the sequence frame by frame to see your work...

**The ATTO R348 is the only RAID controller I know of that has the write performance to allow HD capture using only one controller card. Otherwise you will need TWO controllers (such as Adaptec, 3ware, LSI ,etc) and you will have to do a RAID50 configuration which is more expensive and yeilds less useable storage.

kobeone
01-30-2008, 10:59 PM
Thanks for the info. ;) $2200 is well out of the price range for what I wanted to spend on the raid controller and hard drives. Would a 3ware card with 256 MB of dedicated ram with four SATA II drives in a RAID5 configuration give me good performance? Giving the hardware I plan to buy, what would be the best RAID configuration?

aglick
01-31-2008, 01:47 PM
Thanks for the info. ;) $2200 is well out of the price range for what I wanted to spend on the raid controller and hard drives. Would a 3ware card with 256 MB of dedicated ram with four SATA II drives in a RAID5 configuration give me good performance? Giving the hardware I plan to buy, what would be the best RAID configuration?


NO - not for uncompressed HD capture or realtime editing. Other than that, it should work ok for you at with DV, HDV, DVCPro and other compressed formats...

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