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Disk cache setup questions
I’m building out a RAID-6 array and I’m wondering where I should keep my AE disk cache once I have it installed. The raid I believe will have read/writes sustained at least 450MB/s with a ProRes 1080/60p 422/HQ/4444 workflow for my editing work–AE sequences will often reside within my PR sequences, unless they become too heavy and I decide it’s now worth setting up a proxy workaround. I currently have a 1TB 7200 RPM internal SATA available for disk cache. Should I keep my cache there, move it to my RAID on the same partition as my media, or split my RAID into two partitions with one dedicated to AE cache?
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8 Replies
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The main factor that matters is this: What disk can be accessed and written to fastest? That is almost always your internal disk. Get an SSD if at all possible.
Also, never put the disk cache on the same mechanical drive as your source media. You don’t want to deal with the latency (either because of seek time or bus speed) of having your disk cache reads and writes competing with reads of your source media.
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Todd Kopriva, Adobe Systems Incorporated
After Effects quality engineering
After Effects team blog
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The Ae cache reads and writes loads of relatively little files. As Todd suggests, an internal SSD will perform noticeably better than the RAID and will not bog down your media drive with lots of IO requests.
Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog – What I’m thinking when my workstation’s thinking
Creative Cow Forum Host: Live & Stage Events -
What is a better scenario for AE cache location…
1) in a subfolder on the OS/Apps drive, which is 2 SSDs in RAID 0
Or
2) on a 12-hard drive RAID 5 SAS which also contains source media (and is somewhat faster than the SSD RAID)
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Hillary, maybe Todd can speak with more authority to this, but I’d say that with with a high-spec RAID like that, this is worth testing and I’d be curious to hear your results.
The disk cache seems to store uncompressed “layer-frames.” For example, a 10-layer, 100-frame composition can generate 1,100 cache files (one per layer per frame, plus one per frame for the comp overall). IOPS will matter, as will the number of cached layers you’re actually trying to use. With large rasters and high bit depths, the individual cache file sizes can be quite large, too.
When you are re-rendering a changed and not-totally-cached comp, this can add up to quite a lot of disk access, so the question is which system saturates sooner.
If it’s slower to read from the cache than it is to simply recalculate the layer or frame, Ae will ignore the cache and re-render, so using the cache on a slower drive may not help, but should not hurt.
Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive | RenderBreak [blog] | Profile [LinkedIn] -
Thanks Walter. If I actually do get to conclusively test this, I’ll post results.
That’s some interesting info. I never thought about how read speed would interact with writing to the cache. I didn’t realize it’s caching *each* layer * individually in addition to caching *all* layers.
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[Hillary Knox] “I didn’t realize it’s caching *each* layer * individually in addition to caching *all* layers.”
That’s what makes it so powerful. Changing one thing on one layer no longer requires re-rendering the entire compositing stack from scratch. Instead, Ae can re-render just the changed layer, read the rest from the cache (if they have fallen out of the RAM cache), and re-composite them.
Fun tip: click the wing/panel menu for the timeline, then Ctrl/Cmd+click “Show Cache Indicators.” This will show you per-layer cache indicators in addition to the comp cache indicator.
Just be sure to turn it back off, because it will slow you down considerably.
Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive | RenderBreak [blog] | Profile [LinkedIn] -
> Just be sure to turn it back off, because it will slow you down considerably.
!!! Heed that warning!!!
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Todd Kopriva, Adobe Systems Incorporated
After Effects quality engineering
After Effects team blog
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See this to get a full demonstration of the global performance cache:
https://www.video2brain.com/en/lessons/global-performance-cache-and-persistent-disk-cache———————————————————————————————————
Todd Kopriva, Adobe Systems Incorporated
After Effects quality engineering
After Effects team blog
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