Shrinking cache drive size

[bardsleyb]

I apologize if this is already listed somewhere else, but I searched and did not find it. Here is what I want to do.....

 

My parents have an UnRAID setup I made for them awhile back for Plex to run on docker and Blue Iris to run on a VM for their cameras and it has been working well over the years. At the time I used WD Purple 2TB drives in a 2 drive cache pool to hold their VMs and dockers and such. One of those 2 drives is now failing. I spoke to my folks about their options and explained SSD drives and they wish to use that instead. They don't want to buy the same 2TB size though in an SSD due to the very high price, but they don't mind a 1TB SSD pool. How can I shrink the 2TB dual Drive WD Purple Cache pool down to a 1TB dual SSD pool? I don't have more than about 780 GB or so used for the VDisk and docker stuff currently so the size of 1TB should not be an issue right? I just want to ensure I follow the right procedure so as to not lose their data on there or have to rebuild it all from scratch, cause that would take me hours. 

[JonathanM]

Safest method would probably be to stop VM and docker services, set the shares hosted only on the cache pool to cache:yes, then run the mover. That should empty the cache pool on to the array, then you can remove the cache pool, and recreate it with the SSD's. Change the shares back to cache:prefer, and run the mover again, then enable dockers and VM's.

 

This is all outlined in the wiki BTW.

[JorgeB]

It's possible but somewhat involved to reduce the file system size and do an online replacement of both devices, much easy would be to use this procedure, move pool data to the array, replace the pool, restore data to the pool.

[JonathanM]

2 minutes ago, johnnie.black said:

much easy would be to use this procedure, move pool data to the array, replace the pool, restore data to the pool.

Ok, so not in the wiki, but pretty much what I said.

[bardsleyb]

I found the wiki that you mentioned I think. https://lime-technology.com/wiki/Replace_A_Cache_Drive 

Will the array complain that its a smaller sized pool than before? Or if they don't get 2 SSDs and instead get just 1? I am wondering if I need to do a new config on the array, but if I do will I lose my VM and Docker information.

[JorgeB]

16 minutes ago, bardsleyb said:

Will the array complain that its a smaller sized pool than before?

Not if you replace both devices at the same time, just format them and restore data back.