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Velociraptor RAID or bigger 7200 RAID for grading and rendering?

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michael stirling
Velociraptor RAID or bigger 7200 RAID for grading and rendering?
on Oct 24, 2013 at 9:02:58 am

Hi Folks,

We're in the process of speccing a new 'customac' system here and was wondering if anyone has experience with WD Velociraptor RAIDs.

Lets say that 50% of the system's work will be RED EPIC features

The tech who is building our system is recommending 5x1TB raptors as a internal RAID5 then a larger RAID on a file server which would be connected by gigabit ethernet utilising our old drives (we have quite a few 2TB WD caviar blacks kicking around) and an old i5 PC that would otherwise be getting decommissioned.

This would mean in practice that we'd have the client media on the internal RAID but may (in the case of features at least) have to render to the file server RAID

The alternative would be 5x4TB WB caviar black or red as the internal RAID which would deal with all grading and rendering duties.

Thanks,

Michael


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Chris Kenny
Re: Velociraptor RAID or bigger 7200 RAID for grading and rendering?
on Oct 24, 2013 at 9:25:53 pm

[michael stirling] "This would mean in practice that we'd have the client media on the internal RAID but may (in the case of features at least) have to render to the file server RAID"

What format(s) are you generally rendering to and how are you connecting to the file server? Just gigabit ethernet, or something faster?

--
Digital Workflow/Colorist, Nice Dissolve.

You should follow me on Twitter here. Or read our blog.


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michael stirling
Re: Velociraptor RAID or bigger 7200 RAID for grading and rendering?
on Oct 24, 2013 at 9:43:31 pm

For features we generally render 2k 16bit TIFF sequences for DCP and 422HQ movs. This is why at roughly 1.6TB for a feature I couldn't be sure of fitting it on the internal Velociraptor RAID along with the source if we went that way.

And I suppose the solution I'm being offered currently for the file server is just gigabit ethernet as nothing more advanced has been mentioned.

Maybe my question should be is a velociraptor RAID worth the space hit compared to caviar RAID for grading RED and rendering TIFF sequences?

M


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Chris Kenny
Re: Velociraptor RAID or bigger 7200 RAID for grading and rendering?
on Oct 24, 2013 at 10:32:55 pm

Those TIFF sequences are the only thing that'll really push a storage system; native Red footage and ProRes are compressed enough that storage speeds aren't generally a bottleneck unless you're doing something silly like trying to work from USB 2 drives.

Speed on those TIFF sequence outputs is going to get hit hard over gigabit ethernet. Those TIFF frames are ~12 MB each (at 1998x1080 1.85 DCI resolution), so real-time output requires ~288 MB/s of disk performance, and you'll likely get under 100 MB/s over gigabit ethernet. As far as Velociraptor vs. 7200 RPM, personally I wouldn't take the space hit. A 5 drive array with 7200 RPM drives will push over 500 MB/s easily; more than enough for considerably better-than-real time output of those TIFF sequences (if your CPU/GPU are fast enough), for grading from 2K DPX if you ever need to do that, etc.

You might also want to consider getting an SAS RAID controller with external ports and using external RAID boxes, so you can have multiple projects immediately accessible by plugging in different boxes or move boxes between systems. That way you won't have to rotate projects on and off of internal drives. Or, of course, you could consider shared storage that would be fast enough to keep up with uncompressed workflows (10 GbE or FibreChannel, generally), but that starts to run into pretty serious cash.

--
Digital Workflow/Colorist, Nice Dissolve.

You should follow me on Twitter here. Or read our blog.


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Stella Choi
Re: Velociraptor RAID or bigger 7200 RAID for grading and rendering?
on Oct 25, 2013 at 12:37:26 am

I have tested render 1920x1080 dpx to dpx


1TB HDD (WD Caviar black)


3TB Striped RAID Set (Hitachi)


VelociRaptor 1TBx8 RAID5 with mini SAS


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Eric Johnson
Re: Velociraptor RAID or bigger 7200 RAID for grading and rendering?
on Oct 25, 2013 at 4:46:13 pm

Is that second measurement, 3x 1TB HDD's @ RAID0? Or....

Also, are the two non VelocipRaptor volumes internal or externally attached? If external, what bus type?

eric b johnson
online editor | colorist | workflow


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michael stirling
Re: Velociraptor RAID or bigger 7200 RAID for grading and rendering?
on Oct 25, 2013 at 6:46:58 pm

Thanks guys,

I'm guessing that the 8x VR RAID is external SAS and the rest are internal right, Stella?
It's sort of similar but the opposite way round to what I was thinking.

I'm now thinking of a 10Gbe card in the file server and grade machine connected via crossover cable might be a way forward but need to go. I have another option as the new machine this is going in is a hackintosh with thunderbolt so could always go pegasus or drobo. I just need to read more about it ...oh, and finish this feature grade :-)


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Eric Hansen
Re: Velociraptor RAID or bigger 7200 RAID for grading and rendering?
on Oct 26, 2013 at 4:44:13 pm

You don't need a crossover ethernet cable. Macs can autosense.

I'm pretty sure that if you had 8x4TB Hitachis in a RAID5 via SAS, it would throw out the same numbers as the Velociraptor RAID. prolly around 700MB/s. But i've never worked with VR drives before. If you need massive speed, look at SSDs.

I used to grade in a facility that was primarily 1GbE. i installed a 4 drive RAID0 in the Resolve Mac Pro, which gave me a scratch with about 500MB/s. I would leave all the source files on the SAN, since it was all compressed formats and 100MB/s of 1GbE was plenty fast. But then I did all my renders (and the Render Cache) to the internal RAID0.

the bottleneck for me was actually the GPU (single GTX580). If i had a Cubix with multiple GPUs, then I would have gotten a bigger SAS attached RAID and used that as my main volume and wouldn't have even messed with the SAN. 10GbE is a great option, but for hooking 2 computers together is kind of expensive, about $800 each for 10GbE cards in each machine.

e

Eric Hansen
Production Workflow Designer / Consultant / Colorist / DIT
http://www.erichansen.tv


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