I need to attach external USB drives that I use for off-site backup.

I've been told that to make these easily un-mountable in Unraid I should use the Unassigned Devices plugin.

The primary use case is Beyond Compare BC (running in Windows VM) to perform a mirror from a portion of the Unraid array to an external drive, which is periodically unmounted and swapped with off-site storage.

Option 1:

Connect the external USB3 drive dock to a USB3 port on the server that is managed by Unraid. Mount it with Unassigned Devices, and create a share to make it visible to the VMs. Run BC to mirror from an Unraid Share representing part of the Array, to the Unraid share for the external drive. Un-Mount it with Unassigned Devices as required to remove external drive.

Option 2:

Connect the external USB3 drive dock to a USB3 controller that is configured to passthrough to the Windows VM. Mount it as a Windows drive. Run BC to mirror from an Unraid Share representing part of the Array, to the external drive (a local drive to Windows). Unmount using the Windows "Safely remove" function for removable drives.

Would option 1 or 2 provide better performance for the BC mirroring operation?

Edited June 7, 20251 yr by timg11

since this is a VM on unraid? If i'm understanding this correctly...

USB Manger Plugin / Udev rules to script when device is attached / detected. or use unraids vfio folder share???

or use netwrok fiel sharing technology like sftp / syncthing or web rsync???

While I can't vouch for the BC program. form testing wiht other file tranfers I would sugest option 1 as option 2 relies on data in the array whcih in my experience and testing has been file access and disk io problematic in terms of perfomance due to parity.

either way your biggest bottle neck is USB 3.0 sppeds and the file tranfer sppeds using usb3. thus the mention of netowrk file sharing methods.