Native support for evacuating drives.

[GazzaShergar]

As the title suggests this would be pretty handy. I plan to reduce the power consumption of my server by reducing the number of drives whilst increasing capacity. As I replace drives it would be great if I could hit a button like the mover function and evacuate all the data off a given drive and spread it across the array whilst carrying out parity corrections as I reduce the number of drives . I have used apps to do this in the past however due to either a configuration issue or likely my own stupidity I have ended up with data loss... which manifested itself as approximately 3000 very random missing episodes in my plex media library which took months to rectify.

[JonathanM]

This has been requested before multiple times, and it's definitely in the "too hard to implement properly and safely" bucket.

 

So many different possible ways for people to set up and manage their servers means it's almost impossible to make it fool proof. If Unraid removed the ability for people to use individual drives directly it would be doable, but that's not happening any time soon. For now, you can use Unbalance plugin to clear off a drive, possibly while needing to shut down the entire VM and Docker services, not just the containers, and dealing with any direct referenced drives in your configurations manually.

 

BTW, the way you worded the statement about parity is misleading. Parity is maintained during all normal file operations, including formatting and other file system things. Parity has no concept of files, only bits across the entire capacity of the drive. So in order to remove a drive and keep parity valid, you have to write zeroes to all locations on that drive, including the parts that define the file system. Moving the files off the drive doesn't actually do anything with the bits that made up the file, it just changes the file system table of contents to show the space as available.

 

TLDR; Removing a drive is WAY more complex than adding one. Automating the process isn't going to happen any time soon, if at all.