I want to preface that currently I'm using ZFS in stripe, so one drive, one pool on Debian. I haven't been able to properly test UnRAID being that I don't have spare drives right now, only one, so I'm not sure about the array and how it works. Now my questions:

 

1. I know that transfer speeds are decreased when using parity, will it be even further decreased if I use ZFS? Or will the speed be just like with any other filesystem?

2. When I add drives to an array, the whole array is displayed as a single logical drive or the drives are independently listed? I'm asking because I see a can share entire disks, but if the whole array is one single logical drive how is it that I can export individual drives?

3. About point 2. When I create a share and I select the array for storage, what happens? Let's say I have 2 drives in my array, I select the array and all disks for the share, does this means that a. UnRAID will distribute each single file across all the selected drives (i.e. If I copy some files, for each file X% will be on one drive and Y% on another) or b. UnRAID will distribute whole files across drives (i.e. I copy two files, one file will be on one drive and the other file on other drive)?

4. If I take a drive out of the array, will I be able to attach the drive to another server/computer or even an enclosure and browse the drive contents? (I'm guessing if point 3.a is how UnRAID works the answer to this question must be a No.)

 

My system currently works in that I have every single ZFS drive mounted and I share the whole datasets (1 dataset per pool, so 1 drive 1 pool 1 dataset) on SMB and access each drive through my Windows machine as mounted network shares, so in Windows I have each server drive listed with their own drive letter.

 

I would like to continue using this same system with UnRAID, is this possible?

 

12 hours ago, 1024mb said:

2. When I add drives to an array, the whole array is displayed as a single logical drive or the drives are independently listed?

 

Actually, you can do both.  There are both   User Shares    and   Disk Shares.  User shares are the most commonly used share type. Unraid has several different schemes to determine how the files are allocated to the various disks.  (One thing, writing the first file to one disk, the next file to a second disk, and the third file to a third disk is NOT one of the options!) 

 

12 hours ago, 1024mb said:

3. About point 2. When I create a share and I select the array for storage, what happens? Let's say I have 2 drives in my array, I select the array and all disks for the share, does this means that UnRAID will distribute each single file across all the selected drives (i.e. If I copy some files, for each file X% will be on one drive and Y% on another) or b. UnRAID will distribute whole files across drives (i.e. I copy two files, one file will be on one drive and the other file on other drive)?

 

What happens when you store a file using User Shares is that each file is completely written to just one of the disks in the User Share.   This means that you can remove any data disk from the Array, put in it into any standard Linux computer, and you can access all of the files that are stored on that disk.  This means that a file may be accessed from either the User Share or the Disk Share that the file is stored on.  (Note:  Disk Shares are turned off by default as certain file operations between User Shares and Disk Shares can result in data loss!!!) 

 

IF you want some additional information on User Shares and there their settings, see here:

 

      https://docs.unraid.net/unraid-os/manual/shares/user-shares/#share-settings

Edited April 29, 20242 yr by Frank1940

Thank you, the only thing to be answered is point 1.

 

One thing though, it seems I can't use cache pool with disk shares?

 

EDIT: Yeah, I've searched and everywhere it's said that it's not possible

Edited April 29, 20242 yr by 1024mb

Don't recommend using zfs for the array at the moment, since there's a know performance issue with writes, it doesn't affect pools, only the array.

 

Pools can also be used with disk shares, or exclusive shares.