arc_summary -d error: TypeError: a bytes-like object is required, not 'str'

[loop-evgeny]

System information

Type	Version/Name
Distribution Name	Ubuntu
Distribution Version	18.04
Kernel Version	4.15.0-151-generic
Architecture	x64
OpenZFS Version	Unknown

# zfs version
unrecognized command 'version'

Python 3.6.9

Describe the problem you're observing

arc_summary -d reports the following error at the end of the normal arc_summary output:

...
DMU Prefetch Efficiency:					1.94k
	Hit Ratio:			0.26%	5
	Miss Ratio:			99.74%	1.94k

Traceback (most recent call last):
  File "/usr/sbin/arc_summary", line 991, in <module>
    main()
  File "/usr/sbin/arc_summary", line 986, in main
    page(Kstat)
  File "/usr/sbin/arc_summary", line 865, in _tunable_summary
    description_list = p.communicate()[0].strip().split('\0')
TypeError: a bytes-like object is required, not 'str'

Describe how to reproduce the problem

Run arc_summary -d

[gdevenyi]

Sounds like a python2/python3 problem.

[rincebrain]

#6849

Ubuntu 18.04 ships a highly-patched 0.7.5, which is from December 2017. This was patched in master in November 2017 and in 0.7.x on January 30th.

I suggest you ask Ubuntu to cherrypick it or choose to run a newer version.

[loop-evgeny]

Thanks, I did not find that issue when I searched for "is:issue arc_summary TypeError". Turns out you have to search for "is:issue arc_summary.py TypeError". This is a duplicate, then, closing.