PMDALOGGER(1)

💅 PMDALOGGER — the pmdalogger manual page, but make it make sense

okay so bestie, welcome to pmdalogger(1) 💖 it lives in the General Commands Manual section, and it's about to become your new fave. sit down, grab a strawberry 🍓, let's go.

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✨ NAME ✨

pmdalogger — log file performance metrics domain agent (PMDA) 🎀

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🌸 SYNOPSIS 🌸

$PCP_PMDAS_DIR/logger/pmdalogger [-D debug] [-d domain] [-l logfile] [-m
memory] [-s interval] [-U username] [configfile]

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🦋 DESCRIPTION 🦋

pmdalogger is a configurable log file monitoring Performance Metrics Domain Agent, aka a PMDA. think of it like the -f option to tail(1) but make it ✨metrics✨ — it converts every new log line into a performance event. no cap, it was literally the first PMDA to go hard on event metrics, and those events get consumed by client tools like pmevent(1). iconic behavior honestly 👑

so the logger PMDA exports both:

• event-style metrics, reflecting timestamped event records for text logged to a file (or a whole set of files, or the output from a process) 🔥
• the more orthodox sample-style metrics, like event counts and throughput size values 📊

the whole thing gets configured via a configfile that has one line for each source of events — file or process, your pick. that file is set up by the Install script, which we get into down in the INSTALLATION section. iykyk 💅

here's a quick rundown of the pmdalogger command line options:

• -d — the performance metrics domain number you specify here being unique and consistent is absolutely crucial, like genuinely non-negotiable. domain should be different for every PMDA on the one host, and the same domain number should be used for the same PMDA on all hosts. don't fumble this one 🙈
• -l — where the log file lives. by default, a log file named logger.log gets written in the current directory of pmcd(1) when pmdalogger is started, i.e. $PCP_LOG_DIR/pmcd. and if the log file can't be created or isn't writable? output goes to standard error instead. she adapts 💁‍♀️
• -m — limits the physical memory the PMDA uses to buffer event records, to maxsize bytes. here's the tea: as log events arrive at the PMDA they have to be buffered until individual client tools request their next batch since their previous batch of events. the default maximum is 2 megabytes. remember that 📏
• -s — sets the polling interval for detecting newly arrived log lines. it mirrors the same option from the tail(1) command. cute, consistent, we love to see it 🫶
• -U — the user account under which to run the agent. the default is the unprivileged "pcp" account in current versions of PCP, but in older versions the superuser account ("root") was used by default. glow-up arc 🌈

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💖 INSTALLATION 💖

if you want access to the names, help text and values for the logger performance metrics, do the following as root:

# cd $PCP_PMDAS_DIR/logger
# ./Install

this is an interactive installation process, so it's gonna prompt you for each log file path to be monitored (or command to be run), a metric instance name to identify it, and whether access should be restricted (go peek at the -x option to pmevent(1) for further details 👀).

and if you want to undo the installation, do the following as root:

# cd $PCP_PMDAS_DIR/logger
# ./Remove

⚠️ important bestie: pmdalogger is launched by pmcd(1) and should never be executed directly. the Install and Remove scripts notify pmcd(1) when the agent is installed or removed, so let them handle it, okay? don't do it manually, i'm begging 😭

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🎀 FILES 🎀

• $PCP_PMCDCONF_PATH — command line options used to launch pmdalogger
• $PCP_PMDAS_DIR/logger/logger.conf — default configuration file for the logger metrics
• $PCP_PMDAS_DIR/logger/help — default help text file for the logger metrics
• $PCP_PMDAS_DIR/logger/Install — installation script for the pmdalogger agent
• $PCP_PMDAS_DIR/logger/Remove — undo installation script for the pmdalogger agent
• $PCP_LOG_DIR/pmcd/logger.log — default log file for error messages and other information from pmdalogger

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🌈 PCP ENVIRONMENT 🌈

environment variables with the prefix PCP_ are used to parameterize the file and directory names used by PCP. on each installation, the file /etc/pcp.conf contains the local values for these variables. and the $PCP_CONF variable may be used to specify an alternative configuration file, as described in pcp.conf(5). so much flexibility, we're obsessed 💜

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🔥 DEBUGGING OPTIONS 🔥

the -D or --debug option enables the output of additional diagnostics on stderr to help triage problems — although ngl, the information is sometimes cryptic and primarily intended to provide guidance for developers rather than for end-users. debug is a comma separated list of debugging options; use pmdbg(1) with the -l option to obtain a list of the available debugging options and their meaning 🧚

debugging options specific to pmdalogger are as follows:

• appl0 — configfile processing and PMNS setup
• appl1 — loading event data from the log files
• appl2 — interaction with pmcd(1).

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⭐ SEE ALSO ⭐

PCPIntro(1), pmevent(1), pmcd(1), tail(1), pcp.conf(5) and pcp.env(5).

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and that's the whole page, bestie!! this one's from Performance Co-Pilot, tagged PCP, and it's the PMDALOGGER(1) page in all its glory 💅✨ go forth and monitor those logs, you absolute main character 👑🦋