Cache Drive Suggestions


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So after reading many threads on NAS software and the fact that I don't want just a storage computer I decided to bite the bullet and make a quite overkill server, but I need some help with the cache pool drives.

 

Is there a common rule of thumb on the size of drives you should be using, I will definitely do a cache drive with a parity in-case one fails.

System specs:

mobo: Z10PE-D16 WS

cpu: 2x e5-2690v4

ram: 4x16 ECC

case: supermicro with 1200W dual psu, 24 hot swaps

gpu: W5900 2gb

HBA: 2278300-R Adaptec SAS HBA 71605H Single

drives: 6x8TB (2 parities) helium drives, i have a crapton of 4tb greens and reds but I will use them in a separate enclose as backups.

 

I plan to run Plex, emby, torrent, couchpatoate, and other things related to media library, owncloud, teamspek server, retro game server, probably 2 Windows 10 VMs, and a Ubuntu VM to learn.

 

Anyways, i wonder if 2x1TB enterprise SSDs will do for cache or would 2x2TB drives be a better choice. There has been days that between moving data files and light torrents I can probably move over 1TB of data in one day. Question is how does unRaid handle this, does it just accumulate the data and move it all at night.

 

Is it possible to fill up the cache drive? Will it just start moving files to spinner HDDs at some point once it starts filling up?

 

Thanks for filling in my noobnes on this subject.

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You set the schedule for running the mover. As often as once an hour to as few as once a month. If you ran it twice a day, 2x1TB SSD would be more than enough and you can configure as RAID1 cache pool so you have some redundency on the unprotected data until it gets moved to the array. Its also where all your VMs & Dockers will live.

 

I have 2x275GB in RAID1 and run once a day @3 AM. Never more than half full.

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How about torrents, do they live on the cache drive like everything else till completion?

Everything else doesn't store on cache.

 

Each user share can be configured to use cache or not. Files written to array disks will never use cache.

 

If you save your torrents on a user share that is configured to use cache, then they will stay on cache until they are closed and then moved on schedule. Mover will not move open files.

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Looking through the forums, there has not been a lot of talk regarding NVMe or PCIe based SSDs as of lately.

 

Are there any of these SSDs that are compatible and usable as cache drives?

 

Running 6.2.4 and a 950 pro, it hasn't missed a beat. Those things do tend to run a little bit warm, though.

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  • 2 weeks later...

I was going to go the NVMe route, but my workstation board is c612 chipset and only has 1 m.2 slot, and I prefer redundancy, plus 2 SM863 960GB will serve me well, read/write isnt the greatest, compared to my 850, but it is more suited to server use, plus i got 2 for $240...........cant go wrong there.

 

Hows the heat on those NVMe, I have a 750 pcie and those tings get HOT, kinda why I always stayed away from m.2, with no heatsinks I can only imagine?

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How about torrents, do they live on the cache drive like everything else till completion?

Everything else doesn't store on cache.

 

Each user share can be configured to use cache or not. Files written to array disks will never use cache.

 

If you save your torrents on a user share that is configured to use cache, then they will stay on cache until they are closed and then moved on schedule. Mover will not move open files.

 

I watched a video the other day that explained that putting a SSD cache drive in helps with transfer speeds eg putting the files your transferring to cache first then the "mover" moves them later.

 

If i was to put a cache drive in do i need to enable this ? eg to write to the cache first then the server moves it to the array later or is this enabled by default if the server has a cache drive /

 

my setup is a Parity drive 1 2TB drive and a 128g SSD for cache - if i take the cache drive out would the transfer speeds drop as its writing to the parity drive instead of SSD first ?

 

thanks for reading

 

Happy Nassing

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Seems to me like your question was already answered in my post that you quoted.

How about torrents, do they live on the cache drive like everything else till completion?

Everything else doesn't store on cache.

 

Each user share can be configured to use cache or not. Files written to array disks will never use cache.

 

If you save your torrents on a user share that is configured to use cache, then they will stay on cache until they are closed and then moved on schedule. Mover will not move open files.

 

I watched a video the other day that explained that putting a SSD cache drive in helps with transfer speeds eg putting the files your transferring to cache first then the "mover" moves them later.

 

If i was to put a cache drive in do i need to enable this ? eg to write to the cache first then the server moves it to the array later or is this enabled by default if the server has a cache drive /

 

my setup is a Parity drive 1 2TB drive and a 128g SSD for cache - if i take the cache drive out would the transfer speeds drop as its writing to the parity drive instead of SSD first ?

 

thanks for reading

 

Happy Nassing

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  • 2 weeks later...

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