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Old May 23rd, 2006, 01:41 PM   #16
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Originally Posted by Scott Auerbach
wouldn't a single FW drive for media end up being too slow for HD100? I thought the 7200 rpm drives were still only delivering 60-70Mbs sustained read rates...?
HD100 is 100 MegaBITS per second, which is only 12.5 MB/sec (because 1 MB = 8 Mb), hence easily sustainable on any modern hard drive. I like the idea of splitting source files over different (non-RAID) drives but haven't tested that yet; in theory it should help compared to having everything on one drive.
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Old May 23rd, 2006, 07:50 PM   #17
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Originally Posted by Drew Harty
I have used a SATA raid O on my desktop for a couple years editing uncompressed 10 bit SD with no problems and was going to use two SATA drives with my MBP (when Firmtek releases it new express 34 card) in a raid 1 for instant backup using Soft Raid to record interviews directly from my HVX in 720 24p. Do you think this will be a problem? Are you suggesting firewire drives would perform better in this use?
My suggestion is that there isn't any performance increase for the added cost of SATA in the proposed setup vs. using existing external FW drives.
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Old May 23rd, 2006, 07:56 PM   #18
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I thought the 7200 rpm drives were still only delivering 60-70Mbs sustained read rates...? I thought I'd need at least a 2-drive stripe no matter what the I/O protocol was. Am I (probably) wrong?
The throughput only becomes an issue when you start mulitplying how many streams of HD100 you've put into any timeline.

You're correct, that the average single drive regardless if it's IDE/FW or SATA based is about 65 mb/s. That's plenty for about 3-4 streams of DVCPRO 720p.

With regard to drive optimization, I highly recommend this book for ANYONE who wants to maximze throughput on any Mac-based system:

"Optimizing your Final Cut Pro System", part of the Apple Pro Training series. It deals with literally everything you need to know about the hardware/software environment for editing.

It has chapters that specifically deal with drive types, configurations, SAN/RAID/XSAN setups, video codecs, bitrates - you name it, it's covered.
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Old May 24th, 2006, 09:12 AM   #19
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Fantastic suggestion, Robert...thanks. I hadn't run across that book.

At the risk of overextending my welcome with Godzilla, how do you manage multiple 720p streams from a single drive? If 1080i is 100Mbs, then I assume 720pN30 is roughly 50 Mbs (extrapolating from the P2 capacities). At that bitrate, it seems like 1 stream is all a single drive could possibly handle. What part of the miracle of non-linear editing (and it IS a miracle...I go back to 1" CMX days..<shudder> ) am I overlooking? Even on Avids, I thought the minimum stripe for uncompressed SD is a 4-way of 7200 rpm drives. Is FCP buffering material off onto the scratch disks or something?
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Old May 24th, 2006, 09:29 AM   #20
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Fantastic suggestion, Robert...thanks. I hadn't run across that book.

At the risk of overextending my welcome with Godzilla, how do you manage multiple 720p streams from a single drive?
Taken from Page 410 of the aforementioned book:

DV100 720p60 mb/second: 13.92 mb/minute: 835 mb/hour: 50.1

Multiply the mb/s rate by the number of streams and you'll figure out the maximum streams you can handle.

Now we're talking about RAW footage, not pre-renders or filters mixed in the timeline. Add effects of any kind and you'll decrease the single-drive ability to handle RT playback.

This is where on a NON-RAID setup that multiple drives comes into play - something the book goes into great detail about. As mentioned in my previous post, when you keep application, render, original clips, cache and project files physically separate from each other you dramatically increase the ability of the system to handle multiple streams - of any compressed codec.

With a 4-external drive setup you can very easily do a 4-stream mix of DV100 30p or even 60p; the RT performance then will be determined mainly by how fast the CPU is and how much RAM you have. That doen'st mean that you won't get performance slowdowns during playback with a 4-stream mix, but the "older" PowerBooks (later models) can do it, especially with a 7200rpm MAIN internal drive.

Get the book; I guarantee after 30 mintues of browsing chapters you'll have some eye-opening moments about how to handle FCP in the hardware world.
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Old May 24th, 2006, 09:59 AM   #21
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Originally Posted by Drew Harty
Hello Robert,

Doesn't the throughput of all software controlled raid 0 arrays, whether SATA, firewire, or SCSI, decrease as the drives fill up? (Unless, as you say, there is a hardware controller like Medea uses.)
Actually, there are 2 different degradation issues for the SATA drives:

- One is as you mentioned, where as the drives fill up performance drops off. This is common among all drive configurations even SCSI RAID. It's not specific to being in a RAID configuration at all - any drive slows down when it get's more than 70% full, it's just more noticeable on a video edit system.

- The second type is specific to the SATA RAID setups and occurs immediately as you edit. If you look at the results mentioned in the KONA System test, all 5 tests were done consecutively within a 2 minute period. So, you can see that in less than 5 mintues a significant amount of the maximum throughput has been lost to the drive-cache being "hammered" and full.

(NOTE: When doing this KONA System test, I noticed that the drives got really hot - hotter than normal. The supposition is that because the drive is working so incredibly hard at moving big chunks of data in and out - constantly - that the on-board cache is being pushed to it's limit, literally. This also made me very nervous about trusting an eSATA setup over a long period of time because of possible drive or drive controller failure due to the excessive heat).

There is one eSATA card that does have on-board cache to help prevent this very issue, but it's only in a PCI or PCI-X config and it's about $600. Hardly cost effective compared to external FW when you add-on the cost of enclosures, drives and eSATA cables.
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Old May 24th, 2006, 09:52 PM   #22
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Get the book; I guarantee after 30 mintues of browsing chapters you'll have some eye-opening moments about how to handle FCP in the hardware world.
Clearly! Thanks again!
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