Allocation of Scratch Disks
 

Sorry I'm still learning about scratch disks. Everyone says to have a dedicated HDD for this. Well, going into Premiere's options I see that there are 6 different categories for scratch disks (captured video, captured audio, video previews, audio previews, media cache, DVD encoding).

Now... I don't think that you need a seperate HDD for each of these? Which ones go on a seperate HDD, which ones should not be on the same HDD together, and can any of them be on the same HDD as the project?

Ie... Captured video/audio - could that go onto the project drive without slowing down performance? That doesn't seem like a scratch disk type of thing... unless when you render the timeline, it is best to render the file to a different HDD than the original source AVIs? How does this work?

Then video/audio previews should be on a seperate scratch disk I assume?

Media cache? what is this? does this go on the same drive as video/audio previews?

And what about DVD encoding? Should that be seperate from the drive that your source files (captured audio/video) are on?



Anyway I'm pretty confused about what HDD to put what on, and WHY, if anyone could explain all of this so I not only know what to do but why I should do it, and what the top & lowest priorities are.

Thanks so much!

I put all of my scratch disk files on one drive - a drive dedicated to such things. If I were inclined to write DVDs from Premiere Pro, I imagine that I might be inclined to write them back to my scratch drive. Or my video drive. I doubt it really matters.

I've been experimenting a bit with low cost SATA II drives and raid 0 configs. In this case the RAID chips are integrated with the ASUS P5W motherboard. Where a single drive (7200rpm 300GB SATAII) can just muster just 53 MB/s sustained, the same two drives in a RAID 0 can sustain 107 MB/s. Setting this array as the scratch for all categories makes good sense as data transfer from HD's is the single largest bottleneck on computers these days. It's not a great idea if redundancy and data security is a concern, but it sure makes a huge difference in performance and it's relatively cheap ... 600GB for $200.

It all comes down what formats you edit. For DV/HDV or even uncompressed SD a single SATA II drive will be enough for all scratch disks. If you are doing uncompressed HD, I would recommend putting video scratch disk on RAID 0 made out of 2 or 3 drives.

Should captured Audio/video be on a seperate drive than your project drive?

It was my impression that the "project drive" was the drive that contained all your project files - source footage, renders of the timeline, etc. Why then is it under the scratch disks section?

Will I see improved performance if the HDD that I render files to from the timeline is on a seperate physical drive than the source files?

I think it is mostly for convenience. I myself have project files on one drive (slower, smaller one), source files on another, and render files on yet another. Therefore when I delete the files to make space for other projects, I don't have to deal that much with defragmenting the drives.

Video files (source/render) preferably need fast drives (both in terms of seeking time and throughput) therefore SATA/RAID are recommended. Audio is much less demanding, single IDE/SATA drive will surely be enough.

If you have multiple video streams playing simultaneously on your timeline, then having separate fast drives helps. But if you just have one, hdv or dv compressed, or even SD uncompressed, then it does not really matter, since the throughput of a single drive is enough to get real-time performance.

I have similar setup too. Boot drive( 120G) that also has all programs, Preview drive( 160G) just for previews, project drive (160G)(also stores all stills, titles etc), and storage drives( 3x 200G SATA11 ). I don't have a RAID but ensure that only one camera of multicam shoots is on any one drive, so that no drive is ever outputting more than one stream at a time. All these drives will sustain over 50MBs and for DV only need 3.5MBs!!!!! HDV native is the same its the processor has the decode problem. Depending on what you have for intermediate for HDV going to RAID for captured storage in intermediate form may be usefull as throughput rates could be 4 to 6 times more than DV.

Ron Evans

So do you keep render files (when you export a movie) on a seperate drive as your source files (which are linked to in the timeline)?

When I export, I fully expect that any of my scratch disks can handle a single stream like that. So I generally export to the same disk as the project files.