Disk Cache oddity

[xrekcor]

Hey BScout,

Sometimes when I load a session.... well I have one in particular where I have imported a guitar track from one session into another, both sessions are exactly the same bar one has all it tracks committed to help with latancy issue recording said guitar track. I have them lined up exactly the same in relation to the original I believe they import to the right spot as they are essentially the same session. But for some reason when I first play back it sounds out of time slightly... so I check the alignment to the original but they are exactly the same. then after a short period maybe half a minute or so it rights itself... So just wondering whether maybe this is due to what you are saying about the disk cache.... I have mine set to 10Gb due to me making single song sessions not sure if that is the norm with others but cant see my sessions ever being anywhere near that size.

However when I boot the studio up later ill load that session and give it a minute before I hit play and see what happens.

Originally Posted by BScout

It does try to fill the cache but it does it very, very slowly if you get to work immediately after opening a session. Try opening the session and wait until the disk cache goes green before starting to work on the session.

(and of course, video is never put in the disk cache)

[TrentWilliams]

Originally Posted by Frank Kruse

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

Actually there is, if you go to preferences and enable Tool Tips then hover your mouse over the Disk Cache bar in the System Usage menu, it will show you the total size of all audio on your timeline. Then you can cache your session accordingly.

Screenshot for reference

[Cheesehead]

Well you learn something new every day.
Thanks Trent I didn't know you could do that timeline size thing.


I also didn't know about the pcie capabilities of NVMe SSD's,
thanks Darryl.
A bit off topic but, would an NVMe SSD with a pcie adapter in a sonnet thunderbolt 2 chassis be faster than an sata ssd?



Amazing what you can find out on these threads.

[Darryl Ramm]

Originally Posted by Cheesehead

I also didn't know about the pcie capabilities of NVMe SSD's,
thanks Darryl.
A bit off topic but, would an NVMe SSD with a pcie adapter in a sonnet thunderbolt 2 chassis be faster than an sata.

Everything is faster than SATA Thunderbolt 2 provides 4 x PCIe 2 lanes. So at full tilt it delivers half the bandwidth of a current PCIe 3 M.2 SSD... amazing fast storage devices that cost a few hundred dollars. So sure you can use one of those drives, but will be at degraded performance, not half, but significant, but still faster than SATA. You can google and find benchmark numbers.

Unfortunately you likely end up today doing this via a clunky large external expansion chassis, that lets you choose between some nice M.2 cards. Akitio and others make smaller chassis designed for just M.2 drives, but I have not used them, and you want to be careful with drive cooling and avoid RAID. Manufacturers have really stopped making fast Thunderbolt 2 SSD drives that use PCIe internally, that would have avoided the chassis. The Sonnet Fusion Thunderbolt 2 SSD was nice, as an example. You cannot use Thunderbolt 3 PCIe SSD drives, they are not backwards compatible, so you cannot use the nice Sonnet Fusion Thunderbolt 3 SSD or Samsung X5 SSD drives with a Trashcan. I have a 2TB Samsung X5 hanging off my MacBook Pro i9 as well as a 2TB internal SSD. That is quite enough storage performance (via 8 x PCIe 3 lanes) and capacity for me in a laptop. And the X5 is mostly an alternate boot/test/development drive now.

So that should put in perspective how crippled trash can storage is from a technology viewpoint... more practically sure you only need what you need. And yes you can get IO expansion via Thunderbolt 2 expansion chassis. You may have to watch the other loads on that bus. It may be necessary not to mix audio interfaces and other devices on the same Thunderbolt bus. There are three separate Thunderbolt busses on the Trashcan, each with two Thunderbolt connectors.

And to rub more salt in, the very latest M.2 drives support 4 x PCIe 4... which you only get today in AMD CPU based systems... but folks will have M.2 adapter cards that go from 8 x PCIe 3 to 4 x PCIe 4, so the new Mac Pro users will be able to leverage those drives in 8 x or 16 x PCIe 3 slots at PCIe 4 speeds. The moral of that story is any really pro computer needs to be built around lots of PCIe slot capacity, it is the backwards and forwards compatibility that keeps on giving.

[TrentWilliams]

Hey Frank,

Have you sorted out your caching issues .. ?

[Cheesehead]

Have you sorted out your caching issues .. ?

Yea, sorry, I took Darryl way off topic there, I'll get my coat.
Interesting stuff though.

[Frank Kruse]

Originally Posted by Trent W.

Actually there is, if you go to preferences and enable Tool Tips then hover your mouse over the Disk Cache bar in the System Usage menu, it will show you the total size of all audio on your timeline. Then you can cache your session accordingly.

Screenshot for reference

Ah, thanks! Didn't know about that one. Will keep an eye on it next time PT says it's out of memory with the cache at 10% and significant RAM still available.

F.

[Frank Kruse]

So, I've got a 90-minute film plus 3 episodes in my timeline 250 active tracks. 8GB disk cache. 100% green bar. When I hover over that it says.Cache: 8GB Timeline 0M. The recorded stems alone should sum up to a couple of GB.



I don't really understand, I also don't understand what 100% Memory used means when there are 10GB free. Memory % of what? But I'm moving on now. As a picture editor I used to work with always said: No solution, no problem.

Thanks for your help everyone.

[TrentWilliams]

Originally Posted by Frank Kruse

So, I've got a 90-minute film plus 3 episodes in my timeline 250 active tracks. 8GB disk cache. 100% green bar. When I hover over that it says.Cache: 8GB Timeline 0M. The recorded stems alone should sum up to a couple of GB.



I don't really understand, I also don't understand what 100% Memory used means when there are 10GB free. Memory % of what? But I'm moving on now. As a picture editor I used to work with always said: No solution, no problem.

Thanks for your help everyone.

If the bar is green it means that your timeline has been 100% successfully cached into the memory you have allocated PT to use.

I have noticed today actually, since talking about it in this thread that the hover pop-up will show the correct timeline size when I open a session. But after 10 mins or so, it will say 0M. There seems to be an issue with that. Historically it has always worked as intended.

[Frank Kruse]

Yeah, I get the meaning of the DC bar, but not the memory bar. What's 100% memory usage? All available RAM? I get 100% and an error when there are still 10GB physically available. (see first post of this topic).

Anyway, doesn't matter. Shrug and move on...

;-)