PMDAMEMCACHE(1)

💅 PMDAMEMCACHE(1) — the memcached PMDA, explained by your fave Unix bestie

okay so bestie, welcome to pmdamemcache, a General Commands Manual page for the Performance Co-Pilot (PCP) gang, and honestly? it's giving memcached metrics realness 🧚✨

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🌸 NAME 🌸

pmdamemcache — the memcached performance metrics domain agent (PMDA) 🎀

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💖 DESCRIPTION 💖

so this PMDA's whole job is to pull performance data out of memcached, which is a distributed memory caching daemon that people use all the time to make web serving faster. no cap.

here's the vibe: you can have a whole farm of memcached processes spread across multiple servers, and a single web application can use all of them together. the way that works is it bumps up your total available object cache size 📈 and drops the database load that comes with having a smaller cache. iconic behaviour honestly.

and if you want the full lore, this system is described in detail at http://www.danga.com/memcached 🦋

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✨ INSTALLATION ✨

first things first: you gotta configure pmdamemcache to pull values from the set of hosts in your memcache farm. list those hosts in the $PCP_PMDAS_DIR/memcache/memcache.conf file, in the format (i.e. a Perl array) described at the top of pmdamemcache.pl. you can also set a custom refresh rate using this same mechanism 💅

# cd $PCP_PMDAS_DIR/memcache
# [ edit memcache.conf ]

once that's set up, you can get at the names and values for the memcache performance metrics by doing this as root:

# cd $PCP_PMDAS_DIR/memcache
# ./Install

and if you ever wanna undo the installation (no judgement, we've all been there 🫶), do this as root:

# cd $PCP_PMDAS_DIR/memcache
# ./Remove

🚨 important: pmdamemcache gets launched by pmcd(1) and should never be executed directly. the Install and Remove scripts are the ones that notify pmcd(1) when the agent gets installed or removed. periodt.

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🎀 FILES 🎀

• $PCP_PMDAS_DIR/memcache/memcache.conf — optional config file listing the monitored memcache instances ⭐
• $PCP_PMDAS_DIR/memcache/Install — the installation script for the pmdamemcache agent 🔥
• $PCP_PMDAS_DIR/memcache/Remove — the undo-the-installation script for the pmdamemcache agent 💀
• $PCP_LOG_DIR/pmcd/memcache.log — the default log file for error messages coming out of pmdamemcache 📝

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🌈 PCP ENVIRONMENT 🌈

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

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👑 SEE ALSO 👑

PCPIntro(1) and pmcd(1). go read them, bestie, they're lowkey essential 🍓

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sign-off time 🎀✨ this little love letter to memcached metrics came to you from Performance Co-Pilot — that's the PCP crew — and the page itself answers to the name PMDAMEMCACHE(1). date stamp? the original's footer didn't give us one, so we're leaving it exactly as mysterious as we found it 🙈 stay slaying, and remember: never run the agent directly. bye bestie 💖🦋