Is there a minimum free space that should be left on a spinning data
drive, not SSD?

On 3/30/2022 8:08 AM, Pent wrote:
> Is there a minimum free space that should be left on a spinning data drive, not SSD?

If it accidentally becomes full, that is not the end of the world.
However, you should correct the situation before the next reboot.

The Windows OS is intolerant of not being able to write to C: .
You do not want to shut down the OS while C: is absolutely
full, because you may not be able to start it tomorrow.
As an example, you cannot write out the Registry held
in memory at shutdown, if C: is full.

Data drives like D: or E: should be a bit more tolerant
of being full. However, think of a few fault cases. Say
the E: partition needs a CHKDSK on the next boot, then there
is no room to do anything, for the CHKDSK, and that's bad.

This requires a bit of common sense on the part of the operator.

Sure, I accidentally fill partitions here all the time, while
doing stupid stuff. But I usually erase the offender, before
it is too late for some other emergency condition that might
arise. I don't leave disasters just sitting there. The
"Storage Spaces" may put a notification on the screen,
that something needs attention in that regard.

On Linux, there may be fill rules that prevent 100% usage.
The ordinary users might only be allowed to use 95% of the space.
So Linux/Unix had some rules like that. Whether Windows copied
those ideas, I don't know.

On Windows NTFS, the "Reserved Space" for the $MFT (master file
table) is merely a suggestion. When the disk approaches fullness,
you are allowed to write into the Reserved Space. A consequence of
the Reserved Space behaviors. is the data on the disk may be
fragmented when written, when it would appear to the operator
that no "stimulus" was present to cause the fragmentation. But
part of this is the behavior of Reserved Space for $MFT and what
it does as the disk fills right to the edge.

Paul