Disk Cache oddity

[TrentWilliams]

Your disk cache should only really be set just above the actual size of your session. So if there is only 480MB worth of active audio on your timeline, you should set it to '512MB', if there's 1.8GB; 2GB Ram .. and so on.

Allocating 16GB of ram to a session with 1GB of active audio is wasting your ram.

[Cheesehead]

I've never had any joy with Disc Cache.
You can set it to all sorts of things and it doesn't seem to make any appreciable difference.
Wasn't it just a stopgap at the end of using spinning discs for large sessions?
I guess most serious users now have SSD's which makes cache pretty much redundant.
There should be an option to turn it off I reckon, PT would probably perform better from SSD.

[ZEUSS]

Noticing it not being accurate here as well. Working on a session at 96K. Set my Disc Cache to 40 gigs. Its reflecting the memory usage for sure. Says 56%

The green section "Disc Cache" is saying 7% and its barely filled. Yesterday it was at around 70% filled. Something is off with the system usage window.

[Darryl Ramm]

Originally Posted by Cheesehead

I've never had any joy with Disc Cache.
You can set it to all sorts of things and it doesn't seem to make any appreciable difference.
Wasn't it just a stopgap at the end of using spinning discs for large sessions?
I guess most serious users now have SSD's which makes cache pretty much redundant.
There should be an option to turn it off I reckon, PT would probably perform better from SSD.

There is an option to turn it off that’s normal or standard whatever it’s called. Then AFAIK it just uses the standard system file caching/demand paging.

What SSD? SATA SSD is still pretty slow and will be overloaded by large sessions... so you may be back to round robin striping there. PCIe/NVMe SSD still a lot slower than memory, but do we really need that last bit of speed? Not sure... but with machines with so much cheap memory in them it seems a pity not to use.

If disk cache was causing me real problems today I sure would try setting it to normal and getting the session on a fast SSD (NVNe PCIe 3 x 4). Frank may not be able to do that with a trash can Mac... unless his large session fit on the boot drive and even then that drive is not PCIe 3. The trash can unfortunately is an I/O storage design failure...

[JFreak]

Originally Posted by Darryl Ramm

The trash can unfortunately is an I/O storage design failure...

Wasn't in 2013 but in retrospect it should have had two bays and PCIe 3.0

[Darryl Ramm]

Originally Posted by JFreak

Wasn't in 2013 but in retrospect it should have had two bays and PCIe 3.0

It absolutely was a fail in 2013. The whole design was stupid even then. It could have had PCIe slots... as you say. Or could have had at least two M.2 like SSD slots, with all PCIe 3.

Booming PCIe SSD adoption should not have been a surprise for anybody. Apple themselves by then were one of the worlds largest purchasers of (large amounts of FusionIO) PCIe slot SSD drives for their server farms. So why did they accept crippling their own "Pro" computer? And they could have made all the slot ports PCIe 3 had they wanted to. Instead they made a half-assed box that was not great at graphics and not great at storage.... not for the obviously coming PCIe storage world. But it was "cute" and compact... not anything I knew anybody was asking for. Sorry, just my rage against awful, stupid design. The new Mac Pros look great, just unfortunately held back by being tied to Intel and PCIe 3. Now the irony is with Mojave the Mac Pro Cheesegrater Classic has way better PCIe SSD storage options than the Trashcan.

[Frank Kruse]

Originally Posted by Trent W.

Your disk cache should only really be set just above the actual size of your session. So if there is only 480MB worth of active audio on your timeline, you should set it to '512MB', if there's 1.8GB; 2GB Ram .. and so on.

Allocating 16GB of ram to a session with 1GB of active audio is wasting your ram.

Couple of things (not all in response to your remarks):

-I'm not on a trash can (see below)
-It's not possible to determine the total size of all audio in a film mix session because we work with complex folder structures for workflow reasons and there's no way to see the total amount of audio that's actually in the timeline.
-Like I wrote earlier, I have 20 45minute episodes in my session and it's pretty safe to say that the audio contained should be WAY more than 16GB. The stems alone are beyond that. That set aside it shouldn't be *my* job to tell the computer how much RAM the session needs.
-I use "memory clean 2" to show total memory used and to free up RAM when it's inaccessible by programs.
-And yes, the system usage info doesn't really make sense in relation to what really seems to be going on and caching seems to be broken as it sometimes gets stuck at 5% and other times it's filled to 100% in the same project (see initial posts I wrote)

F.

[Frank Kruse]

Originally Posted by Farhoof

Frank, set "parallel task optimization" lower or disable it.

thanks! I'll try that.

F.

[Darryl Ramm]

Originally Posted by Frank Kruse

Couple of things (not all in response to your remarks):

-I'm not on a trash can (see below)

F.

Oops very sorry I was confusing you/this thread with another one recently. If this is affecting your productivity now I'd be trying out the content on a PCIe/NVMe SSD drive in a PCIe slot and disk cache set to "normal".... especially since you are on Mojave and it has good NVMe support built in.

[FilterDecay]

Originally Posted by Frank Kruse

Couple of things (not all in response to your remarks):

-I'm not on a trash can (see below)
-It's not possible to determine the total size of all audio in a film mix session because we work with complex folder structures for workflow reasons and there's no way to see the total amount of audio that's actually in the timeline.
-Like I wrote earlier, I have 20 45minute episodes in my session and it's pretty safe to say that the audio contained should be WAY more than 16GB. The stems alone are beyond that. That set aside it shouldn't be *my* job to tell the computer how much RAM the session needs.
-I use "memory clean 2" to show total memory used and to free up RAM when it's inaccessible by programs.
-And yes, the system usage info doesn't really make sense in relation to what really seems to be going on and caching seems to be broken as it sometimes gets stuck at 5% and other times it's filled to 100% in the same project (see initial posts I wrote)

F.

hey Frank,


I dont think diskcache is the best solution for a super session. The reason is the disk cache alwasy wants to cache 2:1 ratio in front of and behind the playback head. So if you are jumping around a session you are constantly having disk cache work. You arent lowering the use on your drive in fact you could be making it more depending on how much you are jumping around. I would try not running disk cache unless you are in mix with 1 show only.