[LU-18418] add "lctl find_param" option to search for a parameter name

• Type: Improvement
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.17.0
• Affects Version/s: Lustre 2.17.0
• Labels: easy utils
• Severity: 3
• Assignee: Fred Dilger
• Reporter: Andreas Dilger

Description

Often it happens that I know a specific parameter name exists, but I don't know the exact parameter name, like "brw_stats" is at "osd-ldiskfs.*.brw_stats" but it used to be at "obdfilter.*.brw_stats", while "brw_size" is still at "obdfilter.*.brw_size".

It would be useful to have an option like "lctl find_param PARAM" that is similar to "lctl list_param -R '*' | grep PARAM" to at least list the parameter names, or possibly also printing the value of these parameters by default, while allowing "-n" and "-N" arguments to to print only the pameter name or value, as needed. It should also be possible to use "--path|-p" to print the actual pathname instead of the formatted parameter name.

Issue Links

• is related to: LU-16931 add lctl mechanism (list_param?) to report changes to tunable parameters
• is related to: LU-14590 add output aggregation for "lctl get_param"