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Advice please. Annoying RAID/MAC Pro problem

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Chris Simpson
Advice please. Annoying RAID/MAC Pro problem
on May 25, 2012 at 3:24:24 pm

I do a lot of multiclip sequences editing, in fact thats pretty much all I do. I tend to run 8 Atomos Ninjas, shooting 1920x1080 Pro LT, and anywhere between 1-4 Go pros which I convert Pro Res LT. The Ninjas record in 4GB 6min files, so I drop these into timelines, along with the converted go pro footage, and make reference movies (not self contained) with the Make Quicktime Movie facility. The resulting clips are about 15min long, so anywhere from 8-12 streams of 15min Pro Res LT. It's a fairly old Mac 1,1 I'm using Dual Core 3Ghz, 12GB ram.

Now here's the thing. My RAID Proavio box, 8 x1TB WD Caviar Green drives about 18mths ago, preceded by a strong sense of burning, my Highpoint 3524 card failed, and the raid disappeared off my desktop. Never to return. I got a second Highpoint card, got back to work, fine, 15mths later a similar thing happened again, the card didn't disappear and I could access files on the raid, but it would no longer push the streams it had before, and dropped frame, etc warning kept coming up. Having learnt my lesson a purchased an Areca ARC 1882x, and it's up and running again. However and here is the nub of my post, the RAID is struggling to push 12 streams of Pro Res LT in multclips. It's all set to dynamic, safe or unlimited RT, I get 15-20secs then the warnings start again about a slow system or close open sequences, etc, etc.

I've regularly run AJA system test, and while messing about trying to get the raid working again, I temporarily put 3 Seagate 2TB drives and internally raided them raid 0, the system test gives me write and read speeds around 350MB/s and the graph shows it's also a consistent line. The RAID 5 enclosure on the other hand running the same 4GB 1920x1080 10 bit file gives an up and down trace over the test - read varying from less than 100 to over 1000 and write a steady line over 1100 for a third of 4 GB 1920/x1080 10bit file before falling to around 600-700. The average write speed is about 700MB/s, and the read is 450MB/s. Which along with inconsistent graph line puzzles me as I remember when I first got my RAID it was both WRITE and READ in excess 700MB/s and this is really it, I feel sure it had no problem at all with 12 streams of Pro Res (I used to convert HDV tape before getting the Ninjas).

Before buying the new RAID card I tested each (now reformatted) individual drives from the RAID separately and got Write/Read speeds 65-110MB/s, the 3 lowest speeds I replaced with new drives just for piece of mind when I rebuilt the raid with the new card. So that left the lowest speed around 95MB/s.

Now here's my simple maths, forgive me, if I'm too simple, 12 streams of Pro Res LT (@85Mb/s or 10.7MB/s). Or 1027.2 Mb/s or 128MB/s, the AJA system test I'm getting average write speeds around 700MB/s and read speeds around 420MB/s, the pipe, if my simple math/understanding is right, ought to be wide enough. Which leaves me puzzling over the inconsistent speed over the course of the AJA test.

I'm now wondering what to do? I can't decide if I need to replace the other drives in the raid, or there's something wrong internally with the Mac, although if there is why does the internal RAID work so well (well up to 350MB/s)? Or whether I need a new Mac Pro. Or did I imagine I could run 12 streams of Pro Res. I've checked the slot utility I have ATI HD4870 in slot one (x16) and the RAID card in slot 4 (x8)

I can't find but read on here that AJA test should be a straightline graph, which has got me thinking i have a wide enough pipe through which to pour the video streams, but either the pump (the Mac - in some odd way) or the tanks (the RAID drives) are not feeding the pipe consistently enough. Excuse the dodgy plumbing metaphor. The RAID itself says it's running fine on all it's diagnostics. Activity Monitor shows no signs of a resources hog, and the Mac's RAM is showing up as all there in the system profile. I don't have a second Mac Pro, although I'm toying with hiring one for a month and shifting the card, FCS3 over to rule in, or out my trusty Mac Pro.

Anyone got any ideas, of the what, and how to diagnose, and indeed the fix?


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Shane Ross
Re: Advice please. Annoying RAID/MAC Pro problem
on May 25, 2012 at 4:18:49 pm

Caviar Green drives are slow. 5400rpm opposed to the 7200rpm needed for video. That and their spin speed isn't consistent. Performance will dip, often. They aren't designed for the rigors of video. They are designed to conserve energy (thus GREEN). You need Caviar Black drives for video. And yes, they cost more

Shane
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Read my blog, Little Frog in High Def


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Chris Simpson
Re: Advice please. Annoying RAID/MAC Pro problem
on May 25, 2012 at 7:03:41 pm

The extra money, at least for a solution is not a problem, certainly not bothered by token greenism, but I could have sworn caviar green were 7200rpm, nothing on the drive, and spec sheet only say "intellipower". So Caviar Black the best? I'm always partial to WD scorpio black for my 2.5 Ninja drives, I've always been partial to Seagate Barracudas for 3.5" internal drives.

So fastest, reasonably quiet, reliable, 7200 rpm 3.5" drives for RAID use? Caviar Black?


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Shane Ross
Re: Advice please. Annoying RAID/MAC Pro problem
on May 25, 2012 at 10:12:29 pm

[Chris Simpson] "but I could have sworn caviar green were 7200rpm, nothing on the drive, and spec sheet only say "intellipower"."

They MIGHT be 5400. WD says they might be one or the other...but won't specify. That to me is VERY cagey. I got that info here:

http://techreport.com/articles.x/16393

"The company will only say that the spindle speeds for these drives sit between 5,400 and 7,200RPM, with rumor, speculation, and deduction pegging speeds closer to the former than the latter."

YOu don't know what you are getting with Green. So go with the drives that you KNOW are 7200. BLACK are. Even BLUE are often 5400.

Shane
Little Frog Post
Read my blog, Little Frog in High Def


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