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nvme m.2 as OS and drivepool write cache?



Hey guys, I'll preface by saying thanks for any responses.  I'm in the process of basically overhauling my entire home network (cat6A wiring & ubiquity ecosystem immediately - 10G switch later this year), main workstation, and server (due to trickle down economics of workstation upgrade).  

My current server has met my needs for the past 5 years or so, but is a very basic (aging) win10 box with only spinners for mass storarge (30TB currently) and an old SSD OS drive that doesn't write any faster than the spinners, so I've not implimented ssd write caching (and am maxed out on SATA ports).

The new server has 2 main goals, switch to a plex implementation for transcoding/remote viewing and take advantage of 10G home network (ssd write caching) for faster video transfers.  My current workstation has a 512GB 950 Pro m.2 nvme drive that I've outgrown in capacity for my main workstation and will be replacing for my next build.  I'd like to know if I can carryover this 950 pro drive as I transition my current workstation into my new home server to use as both the OS drive and the write cache for the server?  I'm aware of the immediate duplication setting I will need to change.  I'm not concerned about the time it takes to move data off the write cache to the duplicated drivepool.  Can I use the 950 as an OS drive and the single write cache for my pool to maximize transfer speed for my future 10g network?  If so should I plan on separating the OS from the write cache with different partitions or any other tips?


Future Sever (mostly current WS parts):

Intel 6700k, Asus Maximus VII Gene MB, 32 GB Ram (plan to use 1/2 for ram disk for plex transcoding), need to purchase 1660 super or p2000 for transcoding, used supermicro server chassis w/ x16 hot swap ordered, LSI SAS 9207-8i HBA, and migrate 30TB drivepool plus toss in a couple of random spinners that I have lying around and I didn't have room for before.  No virtual machines or anything else taxing planned.


Am I neglecting to see something?  Thanks again for the help and suggestions!

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What I think I know and would do is : Yes, you can use the C:\ drive as part of the Pool. The OS itself won;t be in the Pool but part of the Pool will be written to the hidden Poolpart.* folder that will be placed on the C drive. Personally, I would consider doing it with a separate partition as it makes it easier to backup/restore/reinstall the OS itself.

It is in fact possible to use one SSD with x2 duplication (even though I consider it a bug and would not do it). You would have to split the x2 Pool first into two x1 Pools and then create a Hierarchical Pool consisting of the x1 Pools and let that Pool have x2 duplication. You'd be doing a lot of seeding. The SSD would have to have two partitions, each would serve as SSD cache for the x1 Pools. Haven't done it, it has been written in the forums, I would not do it. AFAIK, there is no immediate/delayed duplication option in DP (but I could be wrong).

Does Plex use Hardlinks? I don;t know Plex nor understand what hardlinks are but DP does not support them as I read on this forum. Still, many use Plex so some setup must be successful.

Anyway, that is going to be a nice server (and network)! GL.

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Thanks for the response Umfriend! 

Honestly, I'd never even considered their could be issues or specific settings needed to make plex work with DP.  I'll definitely look into this to understand if I need to expect to do anything special.

As for the immediate/delayed backup, there is a DP flag somewhere to disable the immediate duplication requirement that is turned on by default.  I looked into this before I realized how old/slow the ssd in my server was for write speeds (130MB/s).  Ok I just found one reference to disabling real time duplication here: 

 I did not remember the file lock comment or one time a day statement.  Guess I'll have to look into it more, I might have previously found an updated comment from someone if they improved it.  Perhaps my memory of when I previously looked into it betrayed me.  Atleast I plan of having both servers setup concurrently at first so I could tinker briefly with these kinds of options.

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This might have been a better question for the general section, sorry.  But I think I can accomplish what I want with the following settings


512GB nvme m.2 split into two partions, ~68gb OS and ~400GB cache.

Real time duplication turned off

Balance immediately turned on (with sub setting of "not more than" disabled)

ssd optimizer installed

400 gb cache partion be the only flagged ssd

fill ssd drives up to 0%


With these setting every time a file is copied to the pool it lands on the nvme first then is migrated completely off the nvme duplicated in the pool itself.  I don't believe I have any file lock concerns as I won't be accessing the new files until they've been duplicated in the pool and I don't run any kind of DBs.  I might look into turning background balancing off to speed the copies to the pool as well (yes, server performance hit while occurring). 

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