Running 2 Rocket-X cards on the same DIT system.

[Steven Decker]

I have a 5 week feature coming up shooting with two Dragons in a couple weeks. I will be running a nMacPro 12 core, 64gb w/dual 700's in the new Sonnet xMac Server TB2 chassis with my Rocket-X card. The production will be renting a Rocket-X with the camera package in an standard Sonnet TB2 enclosure. My primary storage drive is the Maxx Digital 24TB ThunderRaid 2 setup to Raid 5. The production drives will be 4TB GRaids with USB3. I will also be writing to LTO 6. The production will be providing a nMacPro with the same spec's as mine.

I have the option of running 2 separate 12 core systems or I could attempt to run both Rocket-X off my nMacPro in separate TB2 enclosures on different bus's . Has anyone attempted on running 2 Rocket-X cards on one system yet and if so how was the performance. I will be transcoding for editorial and also creating H.264 Dailies to be streamed with Light Iron server to IPads and passing around thumb drives the same day.

Any input on this setup or performance would be appreciated.

Thanks
Steven

 

[Paul E. McCarthy]

1st Question is, will 2 Rocket Xs work together as 1

 

[Nick Pasquariello]

Doozy of a question.

My instinct is to say that you are better off with 2 computers, each with it's own Rocket. But for that to be true, you'll need some sort of shared storage, in this case a NAS that controls it's own flow of traffic (I believe the Maxx Digital RAID you mention is a DAS, and while you could have the second computer access it through the first, you'll lose so much to overhead that it will be a pointless exercise in futility). You'll use one station primarily (if the two computers are different, you'll want the weaker one as your primary station), running all ingests, QC, backup. You'll then have the Secondary station start chugging through Editorial transcodes, with the Primary station kicking in for transcode duty once it's adequately done with ingests, QC, backup, etc.

Without software to gracefully handle all this (LightIron's Outpost system, or Fotokem's nextLab, among others) it will be a huge pain in the ass.

But then, 24TB sounds slightly low for 5 weeks of 2 camera Dragon. Depending on compression ratio. I'd estimate closer to 40TB as an acceptable amount of useable storage, though depending on shooting style, you might be dead in the water with less than 60.

I can tell you that the latest old-Mac Pro, with a Rocket X, can get between 35 to 80 fps transcoding 3:1 Dragon anamorphic to DNxHD 115 or H264 (1080p and 720p). That wide range in fps is due to the content of the frame, and most shots will be between 40-45 fps. I can tell you this because I've been on a project with exactly this setup for the past few weeks.

If you count on 2 hours of footage per shooting day, and you have 1 editorial format and 1 dailies format, you can count on about 2-2.5 hours of transcode time per day. Of course, this clock starts once you get Sound and any CDL/LUT/Looks squared away with the DP, so you might not be able to start this clock until after wrap. Joy of joys.

With 2 computers, and that DAS you've got, you won't get any benefit out of the secondary machine. You could use shuttle drives, but that's certainly an added complication. Either way, a 2nd CPU does not equal 1/2 have transcode time, Rocket or no Rocket.

What I don't know is how a second Rocket in the first computer will affect things. My suspicion is that even if the Rockets work together in harmony, you're running into I/O bottleneck issues with the Thunderbolt bridge.

 

[joe hedge]

Hey Steven, sounds like an awesome gig!

One suggestion I'd make that might (actually will) save a ton of time is to use 8 TB Pegasus2 R4's as shuttle drives to post. In Raid 0 on mine I'm getting 800mb/s, saving you a ton of time getting media off your MaxxDigital raid. They're $1500 each but will pay for themselves pretty quick in transfer time, both on-set and in post. Even though the G-Raids go 220 mb/s they're still going to be the main bottleneck in the system.

Imagine transferring 1 TB in 20 minutes...sound good?