primocache 2.45% hitrate

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Cybermage
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primocache 2.45% hitrate

Post by Cybermage »

Dear Sirs,

I use a lot of vmware workstation and want to use primocache to speedup things. My only problem is i have only a 2.45% cache rate.
someone have a tip how to get a higher cache rating?

With best regards,
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Last edited by Cybermage on Thu Dec 06, 2018 12:35 pm, edited 1 time in total.
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Jaga
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Re: primocache 2.45% hitrate

Post by Jaga »

The first thing you could do is change the Cache Task Strategy from "Read Only" to "Read and Write". At this point, writes are bypassing the cache entirely, and those files aren't being stored in the cache. Usually things that are written to the drives are high-access files, so you'd want them cached after the write finishes.

The second thing, is that (depending on how full your E: and D: drives are), you probably don't have a large enough L2 cache. If we assume that those two drives are about 50% full each, then you are trying to cache over 5.5 TB of data in 55GB of cache. That's a coverage ratio of only 1%, meaning if you read everything on both drives, you'd only be left with 1% of the data in the cache. If the drives are more full than 50%, then it just gets worse. I normally shoot for 10% coverage, or 5% minimum. That would mean you'd want a 500GB SSD caching 5.5 TB of data.

So, depending on how full those drives are, it might be time to invest in a larger SSD as your L2. I just picked up a 500GB SSD for ~$125 US, so they aren't too expensive. If you do though, don't get the cheapest one you can find - sometimes they can't sustain write speeds (like the Inland SSDs).

Lastly, even if you're going to get good hit rates, it can take a while for it to happen as the cache fills up and starts to deliver content instead of the drive(s). That can take days depending on how you use the data, and will definitely improve with the Read & Write strategy.
richardm
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Re: primocache 2.45% hitrate

Post by richardm »

I'm seeing the same thing. VMware Workstation 15 seems to be performing disk I/O in a manner that completely bypasses Primocache. All other apps on my system are being cached just fine but VM disk I/O doesn't show up in the Primocache stats window.

Edit: I didn't grammar correctly the first time.
Last edited by richardm on Thu Apr 11, 2019 4:21 pm, edited 1 time in total.
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Support
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Re: primocache 2.45% hitrate

Post by Support »

@richardm, thank you for the feedback. We'll check this.
richardm
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Re: primocache 2.45% hitrate

Post by richardm »

support wrote: Thu Apr 11, 2019 3:14 pm @richardm, thank you for the feedback. We'll check this.
Let me know if I can assist. I'd be happy to perform testing as I'd very much like to see Primocache work well with VMware Workstation.
ferrari
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Re: primocache 2.45% hitrate

Post by ferrari »

richardm wrote: Fri Apr 05, 2019 4:42 pm I'm seeing the same thing. VMware Workstation 15 seems to be performing disk I/O in a manner that completely bypasses Primocache. All other apps on my system are being cached just fine but VM disk I/O doesn't show up in the Primocache stats window.

Edit: I didn't grammar correctly the first time.
I'm using Workstation Player 15 and Primocache is working fine with the virtual disk.
beavermml
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Re: primocache 2.45% hitrate

Post by beavermml »

i can confirm the cache wont work. using primocache trial 3.0.9 + vmware player 15 on SATA HDD 500GB 7200 RPM + 8GB RAM Lvl1 cache. cache only 7% ( 150M / 2GB read ).
beavermml
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Re: primocache 2.45% hitrate

Post by beavermml »

after some testing i got interesting result.. running crystaldiskmark directly on the host i get around 3GBps... and running crystaldiskmark on the VM ( which reside on the same HDD ) i get around 600MBps.

this means the cache work somehow.. but it doesnt stated that in the primocache gui, it just state Cache Read around 860kb only.. or it may mean the cache is on VMware part.. not primocache.
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