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New RAID & Data speed requirements for all the various cameras & formats

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Gabriel Bergeron
New RAID & Data speed requirements for all the various cameras & formats
on May 9, 2015 at 6:53:33 pm

Hi guys,

I'm building a new RAID and I'm wondering if I should go with an 8-bay route or bigger array. With my Raid card (Areca 1882-ix-12) in RAID5 and drives I intend to use I will get about 850MB/s read & write for an 8-bay solution.
I wonder if building a larger array would provide any benefits in performance in a 4K Resolve grading system.

I'm trying to compile a list of the the data requirements for the footage of all the high end camera but it's been difficult to find. Arri, Sony, Red...
Then there's 4K DPX.
And then there's these Blackmagic camera + the new AJA CION capturing 4K in RAW DNG.
Is Raw DNG more about decoding power than data throughput like Red raw?
What about Blackmagic compressed raw? Requires less data speed but even more decoding power?

Even if an 8-bay would be good enough for all of formats listed above, would a faster array help in any way? Caching, rendering?

Thanks guys!
Gabriel


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Bob Zelin
Re: New RAID & Data speed requirements for all the various cameras & formats
on May 10, 2015 at 6:20:07 pm

AJA Data Calc
http://www.red.com/tools - click on Recording Time

these are tools I use every day. You can put AJA Data Calc on your iPhone if you like. I did.

850 MB/sec is fast enough for any single workstation for any format.
Regular drives, even in a 16 bay will peak out at about 1500 MB/sec in a RAID 5 configuration. Want faster speeds ? Get SSD drives - expensive and small, but faster than anything you can do with SATA drives. I do not believe in striping across multiple chassis to get faster speeds - it's just too risky, if you have a failure.

Bob Zelin

Bob Zelin
Rescue 1, Inc.
bobzelin@icloud.com


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Gabriel Bergeron
Re: New RAID & Data speed requirements for all the various cameras & formats
on May 11, 2015 at 9:39:15 pm

Hi Bob thanks for your answer!

I use AJA system Test all the time but for some reason DataCalc had escaped me until now. thanks!
10-bit 4K DPX is around 850 MB/s right? You don't think an array like mine would be borderline?

And then what about rendering and caching? Would a faster array improve the performance of these tasks in any way ?
I would definitely prefer to keep the drives count as low as possible to minimize the risks but I'd be ready to do a larger if I would get improved speed and performance.

Thanks!


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Neil Sadwelkar
Re: New RAID & Data speed requirements for all the various cameras & formats
on May 15, 2015 at 6:32:19 am

Working with 4k 10 bit DPX is not something that's common. Many cameras shoot 4k, but they all shoot compressed. The largest file-size is created by the Sony F65 whose 4k .mxf files are about 17 GB/min or about 300 MB/sec.

So if you're grading Sony F65, your drive needs to be able to output at least 300 MB/sec to get stable 24fps playback. Of course, the actual playback speed while grading will depend on the grade applied and the GPU's ability to process that.

Alexa, Red Epic are all below the Sony's data rate, at about 170 MB/sec for ArriRaw and nearly that much for the Red Epic at its highest setting.

Your 8-bay will be fast enough for most current cameras.

-----------------------------------
Neil Sadwelkar
neilsadwelkar.blogspot.com
twitter: fcpguru
FCP Editor, Edit systems consultant
Mumbai India


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Gabriel Bergeron
Re: New RAID & Data speed requirements for all the various cameras & formats
on May 20, 2015 at 3:43:06 pm

Thanks Neil for your input.
You're right 4K DPX is not common right now, but 2K DPX has been common so I'm just trying to think ahead.

Thanks for the precisions concerning the speeds.
Even though the data rate can be as low as 150 MB/s, I always assumed it actually required the storage to be faster than that because of all the processing being done. But I guess it doesn't work that way?


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Simon Blackledge
Re: New RAID & Data speed requirements for all the various cameras & formats
on May 12, 2015 at 12:51:18 pm

Never cache to the same drive your reading OCN from.

Never render to the same drive/array your OCN is on.

This will slow Resolve down.

Get a few SSD's internal and raid those for your cache. 3 or 4 if your going 4k.

s



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Gabriel Bergeron
Re: New RAID & Data speed requirements for all the various cameras & formats
on May 12, 2015 at 11:27:06 pm

You're so right.
I'm trying to figure out how much storage space I would need for caching and rendering? How does Resolve behave? Will it keep its cache for a session or for an entire project?

I haven't really gotten into the new cache feature in Resolve 11/12.


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Bob Zelin
Re: New RAID & Data speed requirements for all the various cameras & formats
on May 14, 2015 at 10:34:04 pm

caching applies to Adobe Premiere as well (Preferences> Media> Media Cache). A cheap OWC 256 Gig SSD will work perfectly for 90% of the jobs.

Bob Zelin

Bob Zelin
Rescue 1, Inc.
bobzelin@icloud.com


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Gabriel Bergeron
Re: New RAID & Data speed requirements for all the various cameras & formats
on May 20, 2015 at 3:44:43 pm

Thanks again Bob.
Could I use my boot SSD for cache or I shouldn't do that?


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