EDIT - 20211120 - Edited the page so that it makes more sense. The last couple of edits were out of sequence. Cleaned up a few things, too.

EDIT - 20211107 @ 1324 UTC-7 - Added how to monitor the drive replacement process.

EDIT - 20201206 @ 2216 UTC-7 - Added how to remove a hard drive and replace it with a bigger one to upgrade.

EDIT - 20200311 @ 1859 UTC-7 - Added how to replace a dead hard drive in a btrfs pool.

EDIT - 20191104 @ 2057 UTC-7 - Figured out how long it takes to scrub 40TB of disk space.  Also did a couple of experiments with rebalancing btrfs and …