PrimoCache, Hyper-V, ReFS, Dedupe, Storage Spaces, and Optane!

FAQ, getting help, user experience about PrimoCache
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richardm
Posts: 7
Joined: Fri Apr 05, 2019 3:52 pm

PrimoCache, Hyper-V, ReFS, Dedupe, Storage Spaces, and Optane!

Post by richardm »

I have a corner-case here.
  • ReFS filesystem
  • Storage Spaces mirror (4x HDD - 5TB total)
  • 800p Optane (58GB) as L2 cache
  • ReFS Deduplication turned on.
  • Hyper-V workload
  • 64GB RAM
How would you configure PrimoCache assuming an "I/O blender" workload of different VM's performing many different kinds of access? Given the Optane's high endurance and unwavering SLC-like write speeds I'm looking to really beat this thing up. I'm thinking a short gather interval along with the "averaging" strategy for deferred writes is called for -- what's next?

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support
Posts: 2702
Joined: Sun Dec 21, 2008 2:42 am

Re: PrimoCache, Hyper-V, ReFS, Dedupe, Storage Spaces, and Optane!

Post by support »

Your cache space might not be large enough for caching 5TB HDD. Of course, it depends on how much hot data are used daily. You may try and then see the result. I would recommend individual read/write cache space to avoid writing data flushing out cached read-data, since the cache space is not very large. If your writing workload is not very heavy, you may just use RAM cache (L1 cache) for caching writes only and use the whole SSD cache (L2 cache) for caching reads.
Primo Ramdisk | PrimoCache
Romex Software Support

richardm
Posts: 7
Joined: Fri Apr 05, 2019 3:52 pm

Re: PrimoCache, Hyper-V, ReFS, Dedupe, Storage Spaces, and Optane!

Post by richardm »

I tried the opposite (L1 as read only and L2 as write only) and it didn't work well at all. I wanted the Optane to be used as a "landing zone" for incoming writes but the physical disk activity was high and the disk queue length was long. What worked better was setting L1 cache to zero and setting the L2 to 10%/90% read/write. I'll keep experimenting.

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Jaga
Posts: 484
Joined: Sat Jan 25, 2014 1:11 am

Re: PrimoCache, Hyper-V, ReFS, Dedupe, Storage Spaces, and Optane!

Post by Jaga »

You might want to consider using Stablebit Drivepool's SSD option for creating a 'landing space' on the Optane for incoming files to your pool of drives. It's a more robust piece of software than what Storage Spaces offers, and still works with ReFS.

dtsiapas
Posts: 6
Joined: Fri May 04, 2018 9:15 pm

Re: PrimoCache, Hyper-V, ReFS, Dedupe, Storage Spaces, and Optane!

Post by dtsiapas »

richardm wrote:
Thu Apr 11, 2019 4:27 pm
I tried the opposite (L1 as read only and L2 as write only) and it didn't work well at all. I wanted the Optane to be used as a "landing zone" for incoming writes but the physical disk activity was high and the disk queue length was long. What worked better was setting L1 cache to zero and setting the L2 to 10%/90% read/write. I'll keep experimenting.
Since you are going the Refs route have a look at this thread
viewtopic.php?f=33&t=4747

richardm
Posts: 7
Joined: Fri Apr 05, 2019 3:52 pm

Re: PrimoCache, Hyper-V, ReFS, Dedupe, Storage Spaces, and Optane!

Post by richardm »

Good catch! I have file integrity streams turned off for now.

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