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Feature Request: Disable Windows File Cache

Posted: Sat Jan 18, 2020 10:24 pm
by Jaga
I was working on methods recently of how to force specific files into the cache using a hash calculation program (HashTools). Unfortunately, everything I fed it didn't make it into the large Primocache Cache Task I have setup, and some of it went into the Windows file cache. I understand this is normal behavior, but I'd like to find a way around it.

Using the SetSystemFileCacheSize() API, it is possible to disable and/or set the Windows file cache max size, which would have the effect of forcing greater use of the Primocache tasks.

Given that Primocache is a superior caching mechanism, it would naturally benefit any user of the software. The feature would be disabled by default, but a checkbox and reboot would enable.

Re: Feature Request: Disable Windows File Cache

Posted: Tue Jan 21, 2020 8:14 am
by support
This feature will be helpful to the dual caching issue. We'll study this. Thanks.
The problem is that Windows file caching is layered higher than PrimoCache. That is, if Windows finds the file in its cache, it will not go through the file system structure and then go to volume/disk sectors where PrimoCache stays. So if disable Windows File Cache, Windows has to query file's sector information each time, the performance will be affected.

Re: Feature Request: Disable Windows File Cache

Posted: Wed Jan 22, 2020 9:11 pm
by Jaga
Thank you for the answer Support.

Do you think with faster machines and drives (i.e. recent MB/CPU and NVMe or performance SSD) that the query time would be significant enough to slow down the disk subsystem? Or could the potential gains of using 100% Cache Task queries (and no Windows cache) be beneficial?

Re: Feature Request: Disable Windows File Cache

Posted: Thu Jan 23, 2020 4:58 am
by support
The query time still will be significant especially when there are lots of small files access, for eg, testing 4KB performance.

Re: Feature Request: Disable Windows File Cache

Posted: Thu Jan 23, 2020 8:18 pm
by Jaga
Understood, thank you. I'd still like some way to test, but that's probably outside the scope of the software at this stage. All the tools I can find for managing the Windows File Cache are many years old, and designed for older editions like XP or W7.