RatVega
Enthusiast
Feb 17, 2006, 5:50 AM
Post #2 of 4
(760 views)
Shortcut
|
|
Re: [sonrisa7] hard drives for video editing
[In reply to]
|
Can't Post
|
|
Welcome to VU, Sonrisa!
Wow, this is a lot if info to digest, but I (like you) suspect that someone is suggesting an expensive and probably unnecessary configuration. However, I'm also a little in the dark since I've never used a Media 100 and therefore don't know your old environment.
I'm going to make a couple of assumptions:
1.) BetacamSP = 10-bit uncompressed 4:2:2 datastream.
According to Digistor (who cites Blackmagic Design as their source) 10-bit 4:2:2 PAL standard definition requires 26MB/sec sustained transfer rate.
2.) HD isn't an immediate concern, but a future possibility.
Here's my take:
The G5 quad is the right platform. The best information I have says that PowerMacs won't make the switch to Intel processors until late 2007 based on Intel's forecast for the candidate processor. Even if the switch happens sooner, I doubt you'll be unhappy with a Quad for many years to come. It's about as Mac as you can get.
You need more RAM. 2GB is a minimum number for a dualie in my opinion. I have personally seen FCP grow from 110MB while cutting to 2.55GB of RAM while rendering a "complex" 7 minute timeline of 8-bit DV. Use 4GB as a minimum, up to maybe 8GB if you want to run hard in Motion2, which really likes a lot of RAM and a really fast video card. I can't understand why your Mac distributors aren't aware of this if they're so keen on big, fast disk arrays to feed the RAM.
If it were me, I'd rather have two 20" Cinema displays than one 23". They provide about 50% more desktop space for less than 20% more cost. The 1920x1200 res of the 23" isn't important unless you need to preview HD.
Now to the disks:
26MB/sec could probably be done on FW 800 drives under ideal conditions, but might (as your dealer suggested) drop frames on long transfers. SATA is the answer to your problem.
What you should be looking at is a SATA RAID and a good back-up system. While there are all kinds of RAID systems, the fastest affordable ones are RAID 0 (zero) which is striped and basically undefended. They can crash (which is why you want a back-up system) but I've had RAIDS on OS X using Apple's RAID software for several years and haven't crashed yet... Back up anyway!
I have a 1TB SATA RAID in my G5 dualie (you'll need to go external on a Quad) that cost me a little over $1000 US a year and a half ago. It is simply four additional 250GB SATA drives, a controller card, and a mounting rack. it survived the loss of both processors and a motherboard replacement without losing data. (Back up anyway!) It has benchmarked at over 350MB/sec, but we both know that benchmarks aren't "real world". What it will do in the real world is transfer to the dual-channel Ultra160 RAID in my big G4 dualie at 60MB/sec continuous... I moved a 7.5GB folder between the two machines over gigabit ethernet in just over 2 minutes. I believe the limiting factor is the ethernet (or maybe the Ultra160 controller) because I see internal data moving as fast as 140-150MB/sec in Activity Monitor. Clearly, this is 4-6X the requirement for your video.
Here are the details to getting a RAID that will support your needs for sure:
Use at least a 4-channel controller. (I have a Highpoint RocketRAID 1820A 8-channel controller.) The reason is because you need a separate channel for each drive, and you want at least 4 drives. Highpoint makes a PCI-e board for the Quad.
Buy the new SATA2 drives if you can get them. They are supposed to be faster. This is going to result in a very large data array, but don't worry, you'll fill it up. If you're really concerned, use the little (like maybe 250GB) drives, they're also cheaper.
Why so many/so big? 1.) Because SATA is one drive per channel, so two drives are almost twice as fast as one, and so on until you saturate the PCI interface (which isn't likely in SD...) 2.) Because the key to sustained data rates is to only use the fastest part of the disk for your "working" video data. It turns out that like all drives, some parts are faster than others, and about 60% of the drive is really fast (as in HD fast), so someone figured out that you could actually configure several RAIDs from a large array - one RAID made up of the fastest sectors, and another one (or more) that you can use for "normal" storage. Suddenly, 6-8 drives sounds pretty good...
Just as an example, The guys at barefeats.com tested an 8-channel SATA RAID that ran over 400MB/sec. In US funds, I could build a 2TB, 8-channel SATA RAID for less than $1200 if I used a PC chassis as the box. I would expect 1TB to be fast enough to support 720p HD (120MB/sec.) Nice cases are often a lot more expensive.
I'm sure you'll have questions about this, so please feel free to ask.
______________________________________________________________
Currently on a loaded 2.5GHz G5 dualie/5GB/1TB internal RAID/dual 19" monitors. Final Cut Studio, Adobe Suite, Boris RED. Shooting with Canon.
VU California Crew, Inland Empire Sub-Chapter (paragraph?)
|
