PMDAGFS2(1)

💖 PMDAGFS2 💖

okay bestie, so you know that page in the General Commands Manual called PMDAGFS2(1)? yeah. that one. this is it, but make it cute.

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✨ NAME ✨

pmdagfs2 — the Global Filesystem v2 (GFS2) PMDA 🦋

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🌸 SYNOPSIS 🌸

$PCP_PMDAS_DIR/gfs2/pmdagfs2 [-D debug]

like, that's it. that's the whole summoning ritual 💅

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🎀 DESCRIPTION 🎀

so pmdagfs2 is a Performance Metrics Domain Agent (PMDA) — which is basically the little guy whose whole job is spilling the tea about your mounted GFS2 filesystems, and it gets that tea straight out of the debugfs filesystem. no cap.

🫶 but heads up bestie: this PMDA requires debugfs, and it also needs at least one mounted GFS2 filesystem mounted, or it literally cannot serve you any metric data. it's giving "no filesystem, no gossip".

you can run this PMDA with GFS2 filesystems that are mounted as local filesystems, and with filesystems mounted as shared storage inside a clustered environment. icon ✨. but — and this is the important part — some metrics specifically require GFS2 to be set up in a clustered environment before they can hand over any metric data at all. why? because they're out here expecting locking messages to be passed around via the distributed lock manager (DLM) between the nodes of a cluster, and that's the only way they'll generate their output. no cluster, no messages, no metrics. that's just the vibe 😭

the way you can tell these cluster-environment-only metrics apart? they come with their corresponding control metrics 💅 so you can optionally enable or disable them on systems where you don't wanna monitor them, or where they're just not supported. main character energy fr fr.

and how do you flip those switches? pmstore(3), bestie. use it to assign values to those control metrics and enable them with 1 or disable them with 0. this mechanism is also lowkey a lifesaver on distributions that don't currently have full support for the GFS2 trace-points, or that ship older versions of the GFS2 driver. periodt.

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🧚 INSTALLATION 🧚

to install the GFS2 PMDA, run the Install script as root:

# cd $PCP_PMDAS_DIR/gfs2
# ./Install

and to uninstall it, do this as root too:

# cd $PCP_PMDAS_DIR/gfs2
# ./Remove

⭐ real talk: pmdagfs2 gets launched by pmcd(1) and should never be executed directly. the Install and Remove scripts are the ones that notify pmcd when the agent gets installed or removed. don't skip the middleman, she's doing her job 💅

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🌈 FILES 🌈

• $PCP_PMDAS_DIR/gfs2/help — the default help text file for the GFS2 metrics 📖
• $PCP_PMDAS_DIR/gfs2/Install — the installation script for the pmdagfs2 agent 🛠️
• $PCP_PMDAS_DIR/gfs2/Remove — the undo installation script for the pmdagfs2 agent 🧹
• $PCP_LOG_DIR/pmcd/gfs2.log — the default log file for error messages from pmdagfs2 📝

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💜 PCP ENVIRONMENT 💜

environment variables with the prefix PCP_ are what parameterize the file and directory names that PCP uses. on every installation, the file /etc/pcp.conf holds the local values for these variables. and the $PCP_CONF variable can be used to specify an alternative configuration file, as described in pcp.conf(5). 🫶

[-D debug]

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🔥 DEBUGGING OPTIONS 🔥

the -D or --debug option turns on the output of additional diagnostics on stderr to help triage problems — although ngl the information is sometimes cryptic and is 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 get a list of the available debugging options and what they mean. iykyk.

debugging options specific to pmdagfs2 are as follows:

• appl0 — details of sbstats and worst_glock fetching and refreshing 👑

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👑 SEE ALSO 👑

PCPIntro(1), pmcd(1), pmstore(1) and gfs2(5). go read them bestie, they're all part of the lore 📚✨

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okay that's the whole page!! 💖✨🎀

this cutie came to you from Performance Co-Pilot, under the PCP banner — page PMDAGFS2(1), no date on the tin but it's giving timeless. slay, go monitor some filesystems 🦋💅🌸