Documentation forServer & Application Monitor
Monitoring your applications and environment is a key capability of SolarWinds Observability Self-Hosted (formerly Hybrid Cloud Observability) and is available in the Essentials edition. Server & Application Monitor (SAM) is also available in a standalone module.

Squid (Linux and Unix)

This SAM application monitor template allows you to monitor the performance of a Squid proxy server installed on a Linux/Unix machine by using SNMP monitors and Perl scripts. You can use the SolarWinds Platform agent for Linux or SNMP agentless to monitor.

Prerequisites for SolarWinds Platform agent for Linux

SSH and Perl must be installed and properly configured on the target server. SNMP should be installed and configured for monitoring squid process on target server. Squid SNMP module must be configured on target server:

On Linux/Unix, to enable the SNMP module on Squid, you should use the --enable-snmp option when running ./configure and recompile Squid. Starting from version 3, it should be enabled by default.

For SNMP, Squid uses UDP port 3401 by default. You can change this port by using the snmp_port directive in the squid.conf file.

The following configuration should be present in the squid.conf file:

acl Snmppublic snmp_community < your_community_string > acl APMhost src <IP_address_of_SAM_server> snmp_access allow APMhost Snmppublic

For example:

acl Snmppublic snmp_community public acl APMhost src 192.168.2.3 snmp_access allow APMhost Snmppublic

After these changes are made, restart Squid.

For further information on configuring SNMP with the SolarWinds Platform agent for Linux, see SNMP for agents.

Credentials

Root on the target server.

Tested on Squid 3.1 for Linux/Unix.

Component monitors

Click here for an overview about SAM application monitor templates and component monitors. SAM API Poller templates are also available.

Storage Mem Size

This monitor returns the amount of memory (in kilobytes) currently used to store in-memory objects.

OID: 1.3.6.1.4.1.3495.1.1.2.0

Storage Swap Size

This monitor returns the amount of disk space (in kilobytes) currently used to store on-disk objects.

OID: 1.3.6.1.4.1.3495.1.1.2.0

Page Faults

This monitor returns the number of page faults for the Squid process since it was started.

OID: 1.3.6.1.4.1.3495.1.3.1.1.0

HTTP Reads

This monitor returns the number of times this process called read( ) on HTTP sockets connected to origin servers and neighbor caches.

OID: 1.3.6.1.4.1.3495.1.3.1.2.0

Accounted Memory

This monitor returns the amount of memory allocated by the memory pooling routines. Not the same as the total memory used by Squid.

OID: 1.3.6.1.4.1.3495.1.3.1.3.0

CPU Usage (%)

This monitor returns the CPU utilization, as a percentage, since Squid was started.

OID: 1.3.6.1.4.1.3495.1.3.1.5.0

Stored Objects

This monitor returns the total number of objects currently in the cache.

OID: 1.3.6.1.4.1.3495.1.3.1.7.0

Available File Descriptors

This monitor returns the current number of available (unused) file descriptors.

OID: 1.3.6.1.4.1.3495.1.3.1.10.0

Reserved File Descriptors

This monitor returns the number of reserved file descriptors.

OID: 1.3.6.1.4.1.3495.1.3.1.11.0

HTTP Requests Received

This monitor returns the total number of HTTP requests received from cache clients.

OID: 1.3.6.1.4.1.3495.1.3.2.1.1.0

HTTP Hits

This monitor returns the number of client requests that were cache hits.

OID: 1.3.6.1.4.1.3495.1.3.2.1.2.0

HTTP Errors

This monitor returns the number of client requests that resulted in an error.

OID: 1.3.6.1.4.1.3495.1.3.2.1.3.0

HTTP Received (KB)

This monitor returns the amount of network traffic, in kilobytes, read from cache clients.

OID: 1.3.6.1.4.1.3495.1.3.2.1.4.0

HTTP Transmitted (KB)

This monitor returns the amount of network traffic, in kilobytes, written to cache clients.

OID: 1.3.6.1.4.1.3495.1.3.2.1.5.0

ICP Transmitted (KB)

This monitor returns the amount of network traffic, in kilobytes, used for ICP messages sent to neighbors, not including UDP and IP headers.

OID: 1.3.6.1.4.1.3495.1.3.2.1.8.0

ICP Received (KB)

This monitor returns the amount of network traffic, in kilobytes, used for ICP messages received from neighbors, not including UDP and IP headers.

OID: 1.3.6.1.4.1.3495.1.3.2.1.9.0

Requests From Clients

This monitor returns the number of requests forwarded to origin servers and neighbor caches.

OID: 1.3.6.1.4.1.3495.1.3.2.1.10.0

Errors For Client Requests

This monitor returns the number of errors received from origin servers and neighbor caches.

OID: 1.3.6.1.4.1.3495.1.3.2.1.11.0

Traffic Received From Servers (KB)

This monitor returns the amount of network traffic, in kilobytes, read from origin servers and neighbor caches.

OID: 1.3.6.1.4.1.3495.1.3.2.1.12.0

Traffic Sent To Servers (KB)

This monitor returns the amount of network traffic, in kilobytes, written to origin servers and neighbor caches.

OID: 1.3.6.1.4.1.3495.1.3.2.1.13.0

Clients

This monitor returns the number of clients that sent HTTP requests to Squid since it was started.

OID: 1.3.6.1.4.1.3495.1.3.2.1.15.0

IP Cache Requests

This monitor returns the number of requests received by Squid's IP cache. If the ratio of hits to requests is less than 60-75%, you may want to increase the size of your IP cache.

OID: 1.3.6.1.4.1.3495.1.4.1.2.0

IP Cache Hits

This monitor returns the number of lookups that were hits in the IP cache. If the ratio of hits to requests is less than 60-75%, you may want to increase the size of your IP cache.

OID: 1.3.6.1.4.1.3495.1.4.1.3.0

IP Cache Negative Hits

This monitor returns the number of lookups that were negative hits in the IP cache. Certain failed queries may be negatively cached for an amount of time determined by the negative_dns_ttl directive.

OID: 1.3.6.1.4.1.3495.1.4.1.5.0

IP Cache Misses

This monitor returns the number of IP cache misses.

OID: 1.3.6.1.4.1.3495.1.4.1.6.0

FQDN Cache Requests

This monitor returns the number of requests to the FQDN cache.

OID: 1.3.6.1.4.1.3495.1.4.2.2.0

FQDN Cache Hits

This monitor returns the number of FQDN cache requests satisfied as hits.

OID: 1.3.6.1.4.1.3495.1.4.2.3.0

FQDN Cache Negative Hits

This monitor returns the number of FQDN requests satisfied as negative cache hits.

OID: 1.3.6.1.4.1.3495.1.4.2.5.0

FQDN Cache Misses

This monitor returns the number of FQDN cache misses.

OID: 1.3.6.1.4.1.3495.1.4.2.6.0

External DNS Server Requests

This monitor returns the number of DNS queries made by Squid. This counter is reset each time you reconfigure the running Squid process.

OID: 1.3.6.1.4.1.3495.1.4.3.1.0

External DNS Server Replies

This monitor returns the number of DNS replies received by Squid. This counter is reset each time you reconfigure the running Squid process.

OID: 1.3.6.1.4.1.3495.1.4.3.2.0

External DNS Server Processes

For internal DNS (the default) this monitor reports the number of nameservers that Squid knows about. For external DNS, it reports the number of (running) dnsserver helper processes.

OID: 1.3.6.1.4.1.3495.1.4.3.3.0

Squid HTTP Port Monitor

This component monitor tests the ability of a Squid service to accept incoming sessions. By default it monitors 3128 TCP port.

Top 10 Active Sites

This monitor returns the top 10 of the most visited sites for specific proxy client.

You must specify the correct arguments for this component in the Script Arguments field. This monitor uses the following argument structure:

perl ${SCRIPT} IP_address Path_to_logfile Time

  1. IP_address – This is the IP address of the computer that uses the target squid server as a proxy server. This argument allows SAM to monitor specific proxy clients.
  2. Path_to_logfile – This is the full path to the squid access.log file.
  3. Time – This argument allows a user to get the statistics during the last minute/hour/day/week/month/year.

    For example: if you set Day, you will get the statistic for the last day.

    Possible values: Minute, Hour, Day, Week, Month, Year. By default, this is set to Week.

For Example:

perl ${SCRIPT} 192.168.2.211 /var/log/squid/access.log week

On some machines (Solaris, HP-UX, etc.), this component may not work because SAM cannot copy all of the script to the target server. You should manually copy this script to the target machine. Next, you should change the Script Arguments field by changing ${SCRIPT} to the scripts path. For example: perl /tmp/top10active.pl 192.168.2.211 /var/log/squid/access.log week

Top 10 Blocked Sites

This monitor returns the top 10 blocked sites which the proxy client tried to open.

You must specify the correct arguments for this component in the Script Arguments field. This monitor uses the following argument structure:

perl ${SCRIPT} IP_address Path_to_logfile Time

  1. IP_address – This is the IP address of the computer that uses the target squid server as a proxy server. This argument allows SAM to monitor specific proxy clients.
  2. Path_to_logfile – This is the full path to the squid access.log file.
  3. Time – This argument allows the user to get statistics during the last minute/hour/day/week/month/year.

    For example: If you set Day, you will get the statistic for the last day.

    Possible values: Minute, Hour, Day, Week, Month, Year. By default, this is set to Week.

For Example:

perl ${SCRIPT} 192.168.2.211 /var/log/squid/access.log week

On some machines (Solaris, HP-UX, etc.), this component may not work because SAM cannot copy all of the script to the target server. You should manually copy this script to the target machine. Next, you should change the Script Arguments field by changing ${SCRIPT} to the scripts path. For example: perl /tmp/top10blocked.pl 192.168.2.211 /var/log/squid/access.log week

Traffic Statistic

This monitor returns the total download and upload amount of traffic in MB for specific proxy client.

You must specify the correct arguments for this component in the Script Arguments field. This monitor uses the following argument structure:

perl ${SCRIPT} IP_address Path_to_logfile Time

  1. IP_address – This is the IP address of computer that uses the target squid server as a proxy server. This argument allows SAM to monitor specific proxy clients.
  2. Path_to_logfile – This is the full path to the squid access.log file.
  3. Time – This argument allows a user to get statistics during the last minute/hour/day/week/month/year.

    For example: If you set Day, you will get the statistic for the last day.

    Possible values: Minute, Hour, Day, Week, Month, Year. By default, this it set to Week.

For Example:

perl ${SCRIPT} 192.168.2.211 /var/log/squid/access.log week

On some machines (Solaris, HP-UX, etc.), this component may not work because SAM cannot copy all of the script to the target server. You should manually copy this script to the target machine. Next, you should change the Script Arguments field by changing ${SCRIPT} to the scripts path. For example: perl /tmp/squid_traffic.pl 192.168.2.211 /var/log/squid/access.log week

Process: squid

This monitor returns the CPU and memory usage of the Squid process.