|JBOD before 3.6 or so mixed data between disks in a way that if one disk failed, you needed to treat them all as failed and replace the host|
Also it worth noting, that usage of JBOD isn't recommended for older Cassandra versions, as there are known issues with data imbalance on JBOD.
iirc JBOD data imbalance was fixed in some 3.x version (3.2?)
For older versions creation one large filesystem on top md or lvm device seems to be a better choice.
In my experience, adding a new disk and restarting the Cassandra process slowly distributes the disk usage evenly, so that existing disks have less disk usage
I know Cassandra can make use of multiple disks. My data disk is almost full and I want to add another 2TB disk. I don't know what will happen after the addition.
1. C* will write to both disks util the old disk is full?
2. And what will happen after the old one is full? Will C* stop writing to the old one and only writing to the new one with free space?