How to configure maximum archive size and retention period for Performance Co-Pilot?

Environment

• Red Hat Enterprise Linux (RHEL) 6, 7, 8, 9 and 10
• Performance Co-Pilot (PCP)
• Using the pmlogger system service directly (rather than the deprecated pmmgr) to manage the logger.

Issue

• How to configure maximum archive size and retention period for Performance Co-Pilot?

• We would like to configure maximum log archive sizes and retention period for PCP in RHEL8, RHEL7 & RHEL6, can you please advise where and what configuration needs to be done?

Resolution

Log Retention

Log retention time can be changed with the -k or --discard option in the pmlogger daily script. On PCP version pcp-4.3.2 and later, the log management scripts are run under systemd timers and are tuned by editing/etc/sysconfig/pmlogger_timers and changing the PMLOGGER_DAILY_PARAMS variable.

For cron based log management on versions prior to pcp-4.3.2, edit /etc/cron.d/pcp-pmlogger and add or change variables, e.g.

10     0  *  *  *  pcp /usr/libexec/pcp/bin/pmlogger_daily -X xz -x 3 --discard 30

For version pcp-4.3.2 and later, edit /etc/sysconfig/pmlogger_timers and change the PMLOGGER_DAILY_PARAMS variable.

--discard 30 keeps logs for 30 days (default 14).

Log Compression

Log compression is controlled with the -x or --compress-after option in the pmlogger daily script, eg:

/etc/cron.d/pcp-pmlogger

10     0  *  *  *  pcp /usr/libexec/pcp/bin/pmlogger_daily -X xz -x 5

-x 5 sets compression after 5 days. Once again, for version pcp-4.3.2 and later, edit /etc/sysconfig/pmlogger_timers and change the PMLOGGER_DAILY_PARAMS variable instead of the cron tab entry.

It is strongly recommended to use the default compression options - PCP archive logs compress very well (~ 90%) and the PCP libraries and tools all support transparent decompression on replay. The default is -x 0, i.e. compress whenever a log volume is rolled.

Volume Size

The pmlogger individual volume file size rollover can be set with the -v option passed to the daemon, eg:

/etc/pcp/pmlogger/control.d/local

LOCALHOSTNAME   y   n   PCP_LOG_DIR/pmlogger/LOCALHOSTNAME      -r -T24h10m -c config.default -v 100Mb

-v 100Mb rolls into a new archive every 100MiB. The format is explained in man pmlogger.

Note this will not restrict the daemon to limit archive files to a particular size, it just configures at which size archives files will be rolled over/new archive files will be started.

Root Cause

• The default time for which PCP retains logs is 14 days.
• The default log compression is 0 days (i.e. whenever a log volume is rolled).

Diagnostic Steps

• Log retention is the CULLAFTER variable.

• Log compression is the COMPRESSAFTER variable.

• Volume size is explained in pmlogger(1) and pmlogger_daily(1).

• As of pcp-5.3 and later, root can execute systemctl start pmlogger_daily and with that manually trigger the cleanup/compression scripts which usually are executed shortly after midnight. These scripts are sourcing file /etc/sysconfig/pmlogger_timers. When pmlogger_daily is executed, notification about that appears in /var/log/messages, as per default config. By default, if verbosity is not set and no errors occur, the script is not generating a dedicated logfile. Verbosity can be set for example in setting PMLOGGER_DAILY_PARAMS="-k 20 -VVV" in /etc/sysconfig/pmlogger_timers, the logfile is then appearing as /var/log/pcp/pmlogger/pmlogger_daily.log.

• The cleanup script pmlogger_daily can also be executed directly, options from the commandline can then be used instead of the options from /etc/sysconfig/pmlogger_timers. Example of direct execution:

  /usr/libexec/pcp/bin/pmlogger_daily --discard 3 -VVV -x 4 -k 7

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