The sections in this chapter describe the basic installation and configuration steps necessary to run Performance Co-Pilot (PCP) on your systems. The following major sections are included:
“Product Structure” describes the main packages of PCP software and how they must be installed on each system.
“Performance Metrics Collection Daemon (PMCD)”, describes the fundamentals of maintaining the performance data collector.
“Troubleshooting”, offers advice on problems involving the PMCD.
In a typical deployment, Performance Co-Pilot (PCP) would be installed in a collector configuration on one or more hosts, from which the performance information could then be collected, and in a monitor configuration on one or more workstations, from which the performance of the server systems could then be monitored.
PCP is packaged into a number of basic subsystem types that reflect the functional role of the product components. These subsystems may be installed using the inst or swmgr command:
For complete information on the installable software packages, see the Performance Co-Pilot release notes. For additional information, see the relnotes(1) or grelnotes(1) man pages.
On each Performance Co-Pilot (PCP) collection system, you must be certain that the pmcd daemon is running. This daemon coordinates the gathering and exporting of performance statistics in response to requests from the PCP monitoring tools.
To start the daemon, enter the following commands as root on each PCP collection system:
chkconfig pmcd on /etc/init.d/pcp start |
These commands instruct the system to start the daemon immediately, and again whenever the system is booted. It is not necessary to start the daemon on the monitoring system unless you wish to collect performance information from it as well.
To stop pmcd immediately on a PCP collection system, enter the following command:
/etc/init.d/pcp stop |
Often, if a daemon is not responding on a PCP collection system, the problem can be resolved by stopping and then immediately restarting a fresh instance of the daemon. If you need to stop and then immediately restart PMCD on a PCP collection system, use the start argument provided with the script in /etc/init.d. The command syntax is, as follows:
/etc/init.d/pcp start |
On startup, pmcd looks for a configuration file named /etc/pmcd.conf. This file specifies which agents cover which performance metrics domains and how PMCD should make contact with the agents. A comprehensive description of the configuration file syntax and semantics can be found in the pmcd(1) man page.
If the configuration is changed, pmcd reconfigures itself when it receives the SIGHUP signal. Use the following command to send the SIGHUP signal to the daemon:
killall -HUP pmcd |
This is also useful when one of the PMDAs managed by pmcd has failed or has been terminated by pmcd. Upon receipt of the SIGHUP signal, pmcd restarts any PMDA that is configured but inactive.
If there is a problem with pmcd, the first place to investigate should be the pmcd.log file. By default, this file is in the /var/adm/pcplog directory, although setting the PCPLOGDIR environment variable before running /etc/init.d/pcp allows the file to be relocated.
There are two files that control PMCD operation. These are the /etc/pmcd.conf and /etc/config/pmcd.options files. The pmcd.options file contains the command line options used with PMCD; it is read when the daemon is invoked by /etc/init.d/pcp. The pmcd.conf file contains configuration information regarding domain agents and the metrics that they monitor. These configuration files are described in the following sections.
Command line options for the PMCD are stored in the /etc/config/pmcd.options file. The PMCD can be invoked directly from a shell prompt, or it can be invoked by /etc/init.d/pcp as part of the boot process. It is usual and normal to invoke it using /etc/init.d/pcp, reserving shell invocation for debugging purposes.
The PMCD accepts certain command line options to control its execution, and these options are placed in the pmcd.options file when /etc/init.d/pcp is being used to start the daemon. The following options are available:
See the pmcd(1) man page for complete information on these options.
The default pmcd.options file shipped with PCP is similar to the following:
# command line options to pmcd, uncomment/edit lines as required # longer timeout delay for slow agents # -t 10 # suppress timeouts # -t 0 # make log go someplace else # -l /some/place/else # enable event tracing (1 for connections, 2 for PDUs, 3 for both) # -T 3 |
The most commonly used options have been placed in this file for your convenience. To uncomment and use an option, simply remove the pound sign (#) at the beginning of the line with the option you wish to use. Restart pmcd for the change to take effect; that is, as superuser, enter the command:
/etc/init.d/pcp start |
When the PMCD is invoked, it reads its configuration file, which is /etc/pmcd.conf. This file contains entries that specify the PMDAs used by this instance of the PMCD and which metrics are covered by these PMDAs. Also, you may specify access control rules in this file for the various hosts on your network. This file is described completely in the pmcd(1) man page.
With standard PCP operation (even if you have not created and added your own PMDAs), you might need to edit this file in order to add any access control you wish to impose. If you do not add access control rules, all access for all operations is granted to all hosts. The default pmcd.conf file shipped with PCP is similar to the following:
# Name Id IPC IPC Params File/Cmd irix 1 dso irix_init libirixpmda.so pmcd 2 dso pmcd_init pmda_pmcd.so proc 3 dso proc_init pmda_proc.so |
 | Note: Because the PMCD runs with root privilege, you must be very careful not to configure PMDAs in this file if you are not sure of their action. Pay close attention that permissions on this file are not inadvertently downgraded to allow public write access. |
Each entry in this configuration file contains rules that specify how to connect the PMCD to a particular PMDA and which metrics the PMDA monitors. A PMDA may be attached as a Dynamic Shared Object (DSO) or by using a socket or a pair of pipes. The distinction between these attachment methods is described below.
An entry in the pmcd.conf file looks like this:
label_name domain_number type path |
The label_name field specifies a name for the PMDA. The domain_number is an integer value that specifies a domain of metrics for the PMDA. The type field indicates the type of entry (DSO, socket, or pipe). The path field is for additional information, and varies according to the type of entry.
The following rules are common to DSO, socket, and pipe syntax:
| label_name | An alphanumeric string identifying the agent. | |
| domain_number | An unsigned integer specifying the agent's domain. |
DSO entries follow this syntax:
label_name domain_number dso entry-point path |
The following rules apply to the DSO syntax:
| dso | The entry type. | |
| entry-point | The name of an initialization function called when the DSO is loaded. | |
| path | Designates the location of the DSO. If path begins with a slash (/), it is taken as an absolute path specifying the DSO; otherwise, the DSO is located in one of the directories /usr/pcp/lib or /var/pcp/lib. |
Socket entries in the pmcd.conf file follow this syntax:
label_name domain_number socket addr_family address command [args] |
The following rules apply to the socket syntax:
| socket | The entry type. | |
| addr_family | Specifies if the socket is AF_INET or AF_UNIX. If the socket is INET, the word inet appears in this place. If the socket is UNIX, the word unix appears in this place. | |
| address | Specifies the address of the socket. For INET sockets, this is a port number or port name. For UNIX sockets, this is the name of the PMDA's socket on the local host. | |
| command | Specifies a command to start the PMDA when the PMCD is invoked and reads the configuration file. | |
| args | Optional arguments for command. |
Pipe entries in the pmcd.conf file follow this syntax:
label_name domain_number pipe protocol command [args] |
The following rules apply to the pipe syntax:
| pipe | The entry type. | |
| protocol | Specifies whether a text-based or a binary PCP protocol should be used over the pipes. Values for this parameter may be “text” and “binary.” The text-based protocol is provided for backwards compatibility, but otherwise its use is discouraged. | |
| command | Specifies a command to start the PMDA when the PMCD is invoked and reads the configuration file. | |
| args | Optional arguments for command. |
You can place this option extension in the pmcd.conf file to control system access to performance metric data. To add an access control section, begin by placing the following line at the end of your pmcd.conf file:
[access] |
Below this line, you can add entries of the following forms:
allow hostlist : operations ; disallow hostlist : operations ; |
The hostlist is a comma-separated list of host identifiers; the following rules apply:
Host names must be in the local system's /etc/hosts file or known to the local DNS (domain name service).
IP addresses may be given in the usual four-field numeric notation. Subnet addresses may be specified using three or fewer numeric components and an asterisk as a wild card for the last component in the address.
For example, the following hostlist entries are all valid:
whizkid gate-wheeler.eng.com 123.101.27.44 localhost 155.116.24.* 192.* * |
The operations field can be any of the following:
A comma-separated list of the operation types described below.
The word all to allow or disallow all operations as specified in the first field.
The words all except and a list of operations. This entry allows or disallows all operations as specified in the first field except those listed.
The operations that can be allowed or disallowed are as follows:
| fetch | Allows retrieval of information from the PMCD. This may be information about a metric (such as a description, instance domain, or help text) or an actual value for a metric. |
| store | Allows the PMCD to store metric values in PMDAs that permit store operations. Be cautious in allowing this operation, because it may be a security opening in large networks, although the PMDAs shipped with the PCP product typically reject store operations, except for selected performance metrics where the effect is benign. |
For example, here is a sample access control portion of an /etc/pmcd.conf file:
allow whizkid : all ; allow 192.127.4.* : fetch ; disallow gate-inet : store ; |
Complete information on access control syntax rules in the pmcd.conf file can be found in the pmcd(1) man page.
The following sections offer troubleshooting advice on the Performance Metrics Name Space (PMNS), missing and incomplete values for performance metrics, and IRIX metrics and the PMCD.
Advice for troubleshooting the archive logging system is provided in Chapter 6, “Archive Logging”.
To display the PMNS, use the pminfo command; see the pminfo(1) man page.
The PMNS at the collector host is updated whenever a PMDA is installed or removed, and may also be updated when new versions of the PCP or PCP add-on products are installed. During these operations, the ASCII version of the PMNS is typically updated, then the binary version is regenerated.
Missing or incomplete performance metric values are the result of their unavailability.
The following symptom has a known cause and resolution:
| Symptom: | Values for some or all of the instances of a performance metric are not available. | |
| Cause: | This can occur as a consequence of changes in the installation of modules (for example, a DBMS or an applications package) that provide the performance instrumentation underpinning the PMDAs. Changes in the selection of modules that are installed or operational, along with changes in the version of these modules, may make metrics appear and disappear over time. In simple terms, the PMNS contains a metric name, but when that metric is requested, no PMDA at the collector host supports the metric. For archive logs, the collection of metrics to be logged is a subset of the metrics available, so utilities replaying from a PCP archive log may not have access to all of the metrics available from a live (PMCD) source. | |
| Resolution: | Make sure the underlying instrumentation is available and the module is active. Ensure that the PMDA is running on the host to be monitored. If necessary, create a new archive log with a wider range of metrics to be logged. |
The following issues involve the IRIX operating system and the PMCD:
No IRIX metrics available
Cannot connect to remote PMCD
PMCD not reconfiguring after hang-up
PMCD does not start
The following symptom has a known cause and resolution:
The following symptom has a known cause and resolution:
| Symptom: | A PCP client tool (such as pmchart, dkvis, or pmlogger) complains that it is unable to connect to a remote PMCD (or establish a PMAPI context), but you are sure that PMCD is active on the remote host. | |||||
| Cause: | To avoid hanging applications for the duration of TCP/IP time outs, the PMAPI library implements its own time out when trying to establish a connection to a PMCD. If the connection to the host is over a slow network, then successful establishment of the connection may not be possible before the time out, and the attempt is abandoned. | |||||
| Resolution: | Establish that the PMCD on far-away-host is really alive, by connecting to its control port (TCP port number 4321 by default):
This response indicates the PMCD is not running and needs restarting:
To restart the PMCD on that host, enter the following command:
This response indicates the PMCD is running:
Interrupt the telnet session, increase the PMAPI time out by setting the PMCD_CONNECT_TIMEOUT environment variable to some number of seconds (60 for instance), and try the PCP tool again. |
The following symptom has a known cause and resolution:
| Symptom | PMCD does not reconfigure itself after receiving the SIGHUP signal. | ||
| Cause: | If there is a syntax error in /etc/pmcd.conf, PMCD does not use the contents of the file. This can lead to situations in which the configuration file and PMCD's internal state do not agree. | ||
| Resolution: | Always monitor PMCD's log. For example, use the following command in another window when reconfiguring PMCD, to watch errors occur:
|
The following symptom has a known cause and resolution:
| Symptom: | If the following messages appear in the PMCD log (/var/adm/pcplog/pmcd.log), consider the cause and resolution:
| |||
| Cause: | PMCD is already running or was terminated before it could clean up properly. The error occurs because the socket it advertises for client connections is already being used or has not been cleared by the kernel. | |||
| Resolution: | Start PMCD as root (superuser) by typing:
Any existing PMCD is shut down, and a new one is started in such a way that the symptomatic message should not appear. If you are starting PMCD this way and the symptomatic message appears, a problem has occurred with the connection to one of the deceased PMCD's clients. This could happen when the network connection to a remote client is lost and PMCD is subsequently terminated. The system may attempt to keep the socket open for a time to allow the remote client a chance to reestablish the connection and read any outstanding data. The only solution in these circumstances is to wait until the socket times out and the kernel deletes it. This netstat command displays the status of the socket and any connections:
If the socket is in the FIN_WAIT or TIME_WAIT state, then you must wait for it to be deleted. Once the command above produces no output, PMCD may be restarted. Less commonly, you may have another program running on your system that uses the same Internet port number (4321) that PMCD uses. Refer to the PCPIntro(1) man page for a description of how to override the default PMCD port assignment using the PMCD_PORT environment variable. |