Apologies but I've read through many forums and posts and don't know if I quite understand this process.  I understand Unraid has a plugin (is it by Steini84?) that reads ZFS?  Here's my set up and situation.

 

My current Unraid has more than enough space to accomodate the transfer of data (about 8 TiB) from FreeNAS (ZFS) to Unraid.  My current FreeNAS set up includes 4 - 6 TB in a ZF2 config (can have 2 drive failures and still retain data).  Now I know I could transfer the data from FreeNAS to Unraid via Windows/Samba; however, understand that's slow and will take dayz to do.  If I am reading correctly, I can download a ZFS plugin, pop my 4 FreeNAS drives into my Unraid and transfer data with the "Unassigned Devices" app?  I have more than enough space to accomodate all this...my storage array can physically hold 16 drives and I only have about 6 mounted currently.  

 

Is there a step-by-step guide to doing this?  Only a portion of the data from FreeNAS is backed up to a cloud so data loss would be a concern.  

Hello, you should probably check directly on the support thread for the plugin.

 

10 hours ago, Hawkins12 said:

Only a portion of the data from FreeNAS is backed up to a cloud so data loss would be a concern.  

Given this statement plus the fact ZFS is not natively supported in Unraid, I'd recommend network transfer. Internal transfer wouldn't be much faster than gigabit anyway, so not worth the risk and hassle.