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Re: Caching Options for Downloads Drive

Posted: Tue Jul 02, 2019 2:46 pm
by hshah
Decided to up the L2 to 16GB because I have the space. There hasn't been much activity today because I am tinkering with other things, but here is the current view.

Is what I have set for the block size, deferred write and prefetch etc. appropriate? The block size defaulted to 32KB but the drive's cluster size is 4KB. If I change it to 4KB PrimoCache estimates a 2.32GB memory overhead, vs the 297MB at 32KB. Is it worth changing it to something in between?
Annotation 2019-07-02 154228.png
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Re: Caching Options for Downloads Drive

Posted: Tue Jul 02, 2019 5:30 pm
by ferrari
I would do 16KB block size, and format the hard disk to 16KB cluster size if possible. Not super important though for a downloads cache. I just use whatever keeps the overhead below 1GB of ram because at that point you're just losing performance from not being able to dedicate that ram to L1 cache.

Re: Caching Options for Downloads Drive

Posted: Tue Jul 02, 2019 6:19 pm
by hshah
Cool, changed it to 16KB and it says the overhead is 594MB :)

When you say format the disk, you mean the 2TB one? If so, don't have the capacity elsewhere to dump the data whilst I do that lol. I may do in a month or two, so could do it then :)

Re: Caching Options for Downloads Drive

Posted: Tue Jul 02, 2019 7:45 pm
by ferrari
Yeah the 2TB one. Not that important for your setup though because I doubt the L2 cache will have much work to do for you. With matched block/cluster size I find ssd L2 cache performance to be 95% of native ssd performance, with a bigger block size than cluster size speed drops to maybe 85% of native ssd performance.

Re: Caching Options for Downloads Drive

Posted: Tue Jul 02, 2019 10:23 pm
by hshah
Hmm, I have just rebooted my PC and whilst the cache task is there, the drive isn't present underneath it :(

Re: Caching Options for Downloads Drive

Posted: Wed Jul 03, 2019 7:40 am
by ferrari
Haven't had that happen do you have fastboot enabled?

Re: Caching Options for Downloads Drive

Posted: Wed Jul 03, 2019 12:58 pm
by hshah
ferrari wrote: Wed Jul 03, 2019 7:40 am Haven't had that happen do you have fastboot enabled?
Nope, it is disabled. I added the volume back in, rebooted a few times since and it has stayed, so no idea what happened.

Re: Caching Options for Downloads Drive

Posted: Wed Jul 03, 2019 2:18 pm
by Support
I think in your case you may just set L2 cache 100% read in order to prevent too much wear by write caching. If the D drive is only used for downloading, then I think 8GB RAM is enough and L2 cache is not necessary.

Re: Caching Options for Downloads Drive

Posted: Thu Jul 04, 2019 3:25 am
by ferrari
hshah wrote: Tue Jul 02, 2019 10:23 pm Hmm, I have just rebooted my PC and whilst the cache task is there, the drive isn't present underneath it :(
Just happened to me as well after I installed the latest 1903 windows update, maybe that was your problem too?