[LU-17443] 'lctl set_param -P debug=+XXX' and '... debug_mb=NNN' do not work

• Status: Open
• Project: Lustre
• Type: Bug
• Priority: Minor
• Reporter: Andreas Dilger
• Assignee: WC Triage
• Resolution: Unresolved
• Severity: 3

Description

I was trying to set the default debug level and buffer size across all of the clients in a cluster, and used "lctl set_param -P debug=+dlmtrace+vfstrace" and a second "lctl set_param -P debug_mb=4096" command (as I wasn't sure if "-P" would work with multiple param=value on the same command-line). I confirmed that these parameters were properly being stored in the config llog:

# lctl llog_print params
- { index: 11, event: set_param, device: general, parameter: ldlm.namespaces.*.lru_size, value: 2000000 }
- { index: 17, event: set_param, device: general, parameter: debug_mb, value: 32
- { index: 20, event: set_param, device: general, parameter: timeout, value: 32 
- { index: 23, event: set_param, device: general, parameter: at_min, value: 5 }
- { index: 26, event: set_param, device: general, parameter: debug, value: +vfstrace+dlmtrace+rpctrace }

Unfortunately, this did not result in "debug_mb=4096" being set on the server. I also tested on a local VM (2.14.0-ddn128) and saw the same problem. Other global parameters like timeout and at_min were immediately visible on the client.