Caching Options for Downloads Drive

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hshah
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Joined: Sun Jun 09, 2019 9:41 am

Caching Options for Downloads Drive

Post by hshah » Mon Jun 10, 2019 2:53 pm

I am just having a play around and kind of seeing what my options are. I have a HDD for downloads/torrents etc but Windows/applications all live on a NVMe. Anything download either staying on the HDD for a bit, or gets copied over to my NAS shortly after.

I have ~2GB RAM free and have also tested creating a L2 cache as an image on the NVMe. I had set L1 as 1GB and L2 as 10GB.

Everything appeared alright, but I don't actually know what would be beneficial and wouldn't. Based on what I have said, can anyone suggest anything? I'm thinking that a write cache would definitely help because concurrent downloads tend to put the drive under strain, especially when torrents are involved and they are being seeded. I have Googled a bit and if I read things correctly, L2 for writes could in theory cache a downloaded torrent so that any seeding uses data from there rather than the HDD?

hshah
Posts: 6
Joined: Sun Jun 09, 2019 9:41 am

Re: Caching Options for Downloads Drive

Post by hshah » Tue Jun 11, 2019 1:34 am

Also, I don't fully understand whether the L1 (1GB-2GB RAM) ought to be set as read or write? If both, should the space be shared or have a ratio defined from the start? My L2 is a 12G file-disk on a NVNe, and was set up with RAMDisk as a SCSI. It was then formatted as L2STORAGE in PrimoCache. Similarly, should this one be read/write and shared or have the space defined?

There would be more seeding taking place when new torrents are involved, so it would be beneficial if L2 could serve those requests. The HDD obviously struggles with multiple concurrent read/writes, and that becomes really noticable when my scripts copy the downloaded media over to a NAS and there are still multiple download/uploads going on. Could there a brief delayed write set and L! reserved for that?

Not sure if L1 passes through L2 to get to the HDD, especially if L2 has been set as 100% read. Overall, I've not got my ahead around all this yet so any help would be greatly appreciated :)

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support
Posts: 2406
Joined: Sun Dec 21, 2008 2:42 am

Re: Caching Options for Downloads Drive

Post by support » Tue Jun 11, 2019 4:29 am

I think L1 write-only cache (100% write cache space) with defer-write enabled shall help downloading. You may check the cache statistics to see the performance and tune the configuration.

PS. it is not recommended to use a file-disk or virtual disk as level-2 storage. Dead-lock might happen if doing so.
Primo Ramdisk | PrimoCache
Romex Software Support

hshah
Posts: 6
Joined: Sun Jun 09, 2019 9:41 am

Re: Caching Options for Downloads Drive

Post by hshah » Tue Jun 11, 2019 6:49 pm

support wrote:
Tue Jun 11, 2019 4:29 am
I think L1 write-only cache (100% write cache space) with defer-write enabled shall help downloading. You may check the cache statistics to see the performance and tune the configuration.

PS. it is not recommended to use a file-disk or virtual disk as level-2 storage. Dead-lock might happen if doing so.
I am only able to spare 2GB of RAM at most for L1 so was hoping to back that up with a disk based L2. Was also hoping that placing the image on a NVMe would still benefit the standard HDD.

I could partition the NVMe and allocate L2 to the HDD that way?

I've just noticed that I can't copy some films from the HDD to my NAS... just hangs for ages and then Windows shows some sort of error. I am assuming that is is trying to do something with the cache and then falling over... assuming its down to the file based L2 lol.

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support
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Re: Caching Options for Downloads Drive

Post by support » Wed Jun 12, 2019 1:45 am

hshah wrote:
Tue Jun 11, 2019 6:49 pm
I could partition the NVMe and allocate L2 to the HDD that way?
You may shrink the existing NVMe ssd partition and then create a dedicated partition by spare ssd space for L2 cache.
Primo Ramdisk | PrimoCache
Romex Software Support

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