KERNEL 
PMDAS(1) 					      General Commands Manual						   KERNEL PMDAS(1)

NAME

       pmdaaix,  pmdadarwin,  pmdafreebsd,  pmdalinux,	pmdanetbsd,  pmdasolaris, pmdawindows - operating system kernel performance metrics domain
       agents

SYNOPSIS

       $PCP_PMDAS_DIR/aix/pmdaaix [-d domain] [-l logfile] [-U username]
       $PCP_PMDAS_DIR/darwin/pmdadarwin [-d domain] [-l logfile] [-U username]
       $PCP_PMDAS_DIR/freebsd/pmdafreebsd [-d domain] [-l logfile] [-U username]
       $PCP_PMDAS_DIR/linux/pmdalinux [-d domain] [-l logfile] [-U username]
       $PCP_PMDAS_DIR/netbsd/pmdanetbsd [-d domain] [-l logfile] [-U username]
       $PCP_PMDAS_DIR/solaris/pmdasolaris [-d domain] [-l logfile] [-U username]
       $PCP_PMDAS_DIR/windows/pmdawindows [-d domain] [-l logfile] [-U username]

DESCRIPTION

       Each supported platform has a kernel Performance Metrics Domain Agent (PMDA) which extracts performance metrics from  the  kernel  of  that
       platfrom.   A variety of platform-specific metrics are available, with an equally varied set of access mechanisms - typically this involves
       special system calls, or reading from files in kernel virtual filesystems such as the Linux sysfs and procfs filesystems.

       The platform kernel PMDA is one of the most critical components of the PCP installation, and must be as efficient and reliable as possible.
       In  all	installations the default kernel PMDA will be installed as a shared library and thus executes directly within the pmcd(1) process.
       This slightly reduces overheads associated with querying the metadata and values associated with  these	metrics  (no  message  passing	is
       required).

       Unlike  many  other PMDAs, the kernel PMDA exports a number of metric namespace subtrees, such as kernel, network, swap, mem, ipc, filesys,
       nfs, disk and hinv (hardware inventory).

       Despite usually running as shared libraries, most installations also include a stand-alone executable for the kernel PMDA.  This is to  aid
       profiling  and  debugging  activities, with dbpmda(1) for example.  In this case (but not for shared libraries), the following command line
       options are available:

       -d   It is absolutely crucial that the performance metrics domain number specified here is unique and consistent.  That is,  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.

       -l   Location  of the log file.	By default, a log file named [platform].log is written in the current directory of pmcd(1) when pmda[plat-
	    form] is started, i.e.  $PCP_LOG_DIR/pmcd.	If the log file cannot be created or is not writable, output is written  to  the  standard
	    error instead.

       -U   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.

INSTALLATION

       Access to the names, help text and values for the kernel performance metrics is available by default - unlike most other agents, no  action
       is required to enable them and they should not be removed.

FILES

       $PCP_PMDAS_DIR/[platform]/help
		 default help text file for the the kernel metrics
       $PCP_LOG_DIR/pmcd/pmcd.log
		 default log file for error messages and other information from the kernel PMDA.

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.  The $PCP_CONF variable may be used to specify an alternative	configura-
       tion file, as described in pcp.conf(5).

SEE ALSO

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

Performance Co-Pilot							PCP							   KERNEL PMDAS(1)