I know that 10% of node space allocation is the recommended reserve space for a node. However 10% of a 10TB drive, i.e. 1TB, is a lot more than 10% of a 1TB drive, i.e. 100GB. So how much is really needed to insure proper node operation or does it really vary by node size?
I personally reserve about 100GB no matter the size of the drive. There is no technical reason for the 10% figure as far as I know, and I feel that 100GB should be more than enough space for databases, logs, and the rare case (i.e. bug) where the node could use space beyond it’s allocation.
Does trash need to be accounted for in the reserve space?
no, unless there is a bug in the code.
The reserve is more for safety against the bugs in the code. Most of them are eliminated at this time, so maybe 100GB is a safe limit now. However, it doesn’t guarantee that we would not introduce a bug somewhere after a while.