Add arc_summary.py from FreeNAS
The arc_summary script is a useful utility for administrators on
other ZFS platforms. It provides a quick and easy way to get a high
level view of the current ARC state.
Historically this was a perl script but it was rewritten in python
for FreeNAS. We've decided to adopt the python version instead of
the perl version for a few reasons.
- ZoL has no existing perl dependencies, but it does have a python dependency for scripts such as arcstat.py and dbufstat.py. Using python for arc_summary.py helps us minimize dependencies.
- Most major Linux distributions already depend heavily on python for their core infrastructure. This means it's very likely to be available even very early in the boot process.
Original source:
https://github.com/freenas/freenas/blob/master/gui/tools/arc_summary.py
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: cburroughs <chris.burroughs@gmail.com>
Signed-off-by: Kyle Blatter <kyleblatter@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>