Yesterday, I finished reinstalling a 16TB Unraid 6.0.0 PRO system from scratch (still have to put back all the data files  :'( . My desktop workstation runs Linux (no Win7,8 or 10 involved).

 

Yesterday, I also installed a single WD Green 2TB drive as a single "cache" drive. Today I want to add a second WD Green 2TB drive to the existing "cache" for redundancy protection.

 

Currently, my setup sees the new 2TB drive as an "unassigned Device". I can assign it to the "Array Devices" section, but I can't seem to assign it to the "Cache Devices" section. The new drive appears (along with the first cache drive) in the cache drop down menu, but I can only select one drive. The "Slots" drop down menu only allows the default number "1" to be entered. I'm guessing I need "slots" to allow me to enter "2", but it won't.

 

Is this a bug? How can I get a redundant btrfs two cache drive setup?

 

The built in GUI help file is useless and the Wiki for "Cache Drives" has instructions which are apparently out of date for the new version 6.0.0:

 

Adding a cache disk to the array

 

In order to create a cache disk using the GUI:

 

    Stop the array

    Click on "Disk" at the top.

    Look at the very bottom of the page in the Disk Devices section for a disk 'slot' labeled Cache (the very last slot).

    Select any disk not in the array into that slot.

    Start the array

 

Any help is appreciated.

Have you reduced the number of slots allocated to data drives?  You need to do this to be able to increase the number of cache slots.

No, I didn't do that, but I will try it now and see if that works. Thanks, it worked.

 

Seems this should be semi-automatic, or at least noted in the online help information.