Hey guys.  Been trialing unraid for a couple days now and decided to move from a virtualized OMV to Unraid bare metal.  Im using a Lenovo tiny (p350) with 2x 4tb m.2's (samsung 990's) and a single 1tb m.2 (samsung oem).  Prior, I was using the 1tb drive as the os drive and the 2 4tb's in a 8tb stripe within OMV for my movie (mkv) storage that is accessed by multiple ATV's throughout the house.  

 

The primary purpose of this machine will be simply for NAS share for the movies along with a handfull of docker containers (sabnzb, rust desk, Adguard)

 

Prior to looking into a diy solution I used synology machines and always 2 bay's using raid0.

 

My main goal was to get faster speeds and with an all flash machine.  The OMV machine ill be migrating from is nice and snappy, movies instantly play and can seek to different parts of a movie without any delay.

 

My main question is what would the best practice for my hdd setup with this machine be?  

 

Is a 2 disk striped array possible?

 

Would I need to add another 4tb m.2 to use one as parity?

 

Is a cache drive needed if already using nvme's for storage?

 

Is there a perfered format / file system using unraid to perserve the life of this storage type?

 

Thanks!

 

 

6 minutes ago, illlili said:

...an all flash machine....for my hdd setup

You don't mention any HDDs.

 

You will have to create a pool outside the parity array using btrfs or ZFS to get the performance you want from the SSDs. Also, SSDs in the array cannot be trimmed.

 

Unraid requires at least one data disk in the array to start everything up. A USB flash drive could be used for that if you don't actually plan to use any HDD storage.

 

The Unraid OS itself does not install to any drive. The boot flash drive contains the archives of the OS and these are unpacked fresh into RAM at each boot, and the OS runs completely in RAM. Your configuration (settings from the webUI) are also saved on the boot flash so they can be reapplied at boot.

Thanks for the response, trurl.

 

I get the os usb and ram part of it.  The part Im having difficulty with is the pool / parity and array detail.  The end goal I have is to use the 2 4tb drives mentioned simply as a movie storage and if it can be done without any redundency that works just fine for me.  This machine, in its configuration, is limited to 3 m.2 slots internally.  The os USB is fine as there is no alternative, however if an idditional drive is needed to "start everything up" could that data disk be the 3rd m.2?  Sure I would swap it for a lower volume m.2 if thats the case.

 

Your mention of the needed data disk in the array, would this also be where docker container data should be saved?

 

thanks again

 

 

 

 

Unraid has the "array", which can have 0, 1, or 2 parity disks. This is usually where HDDs will be.

 

Unraid has additional "pools", separate from the array. These are usually where SSDs will be. There can be multiple pools, and each can have a single disk or multiple disks. Multiple disk pools must use btrfs or ZFS. Single disk pools can also use XFS.

 

SSDs in the array cannot be trimmed. At least one data disk is required in the array, whether or not it is used for anything. This is a legacy requirement and will probably be removed in the near future. For your use, a simple USB flash drive could be used there, and you could just ignore it.

 

All array disks and pools are part of User Shares. Each user share has settings to control how it uses the storage.

OK.  Let's break down Unraid's basic structures.

 

The base Unraid file system has two types - Array and Pool.

 

The Array is original to the earliest Unraid OS, and is required to have at least one drive for the OS to work.  The array can contain one or two Parity drive, which use Unraid's non-conventional parity protection (unconventional in it does not follow standard RAID formats, allowing for a mixture of drive capacities).  Due to it's function of updating Parity drives, SATA/NVMe drives cannot be trimmed, as it would invalidate the contents of the Parity drive(s), as Trim changes happen independent of the Unraid OS knowledge.

 

Pool (formerly called Cache, and renamed to Pool when Unraid was updated to allow more than 1 Pool to exist.  Pools can be configured in multiple RAID configurations, and do allow for SATA/NVMe drives to be trimmed.