Last modified: August 9, 2022

Overview

Apache is a web server daemon (httpd). It responds to HTTP requests, and subsequently serves web pages. For example, if one of your visitors requests your domain, www.example.com, from a web browser, Apache serves the index page for www.example.com.

Heading information

This interface displays the following heading information:

• Server Version — The version of Apache that runs on the server.
• Server Built — The time and date at which you installed Apache.
• Current Time — The current time and date.
• Restart Time — The time and date at which you last restarted the server.
• Parent Server Generation — The number of times that you have restarted Apache gracefully, which causes it to re-read its configuration file. This occurs, for example, whenever you add domains to your server.
• Server uptime — The amount of time over which the server has run.
• Total accesses — The total number of requests for your server.
• Total Traffic — The total amount of traffic for your server, in megabytes (MB).
• CPU Usage — The total CPU usage and current load percentage (the percentage of the server’s currently-used processing power). Under the CPU usage, the interface displays the following additional information:
  • The number of requests per second, bytes per second, and kilobytes per request that the server transfers.
  • The number of Apache sub-servers (workers or children) that serve requests.
  • The number of idle workers.

Scoreboard

The Scoreboard section displays the following information about each worker on your server:

• Srv — The worker’s server number.
• PID — The operating system’s process ID number.
• Acc — The number of requests that this worker has served for this connection, this child, and this slot, separated by forward slashes (/). For example, 0/2055/7670 indicates the following request data:
  • 0 requests for this connection.
  • 2055 requests for this child.
  • 7670 requests for this slot.
• M — The mode of operation. This column displays the following modes:
  • _ — The server is waiting for the connection.
  • S — The server is starting.
  • R — The server is reading the request.
  • W — The server is sending a reply.
  • K — The server is in keep alive (read) mode.
  • D — The server received a DNS request.
  • C — The server is closing the connection.
  • I — Idle worker cleanup.
  • . — Idle worker.
• CPU — The worker’s CPU usage.
• SS — The number of seconds since the start of the most recent request.
• Req — The amount of time that the worker required to process the most recent request, in milliseconds.
• Conn — The amount of information that the worker transferred to the visitor, in kilobytes (KB).
• Child — The total amount of information that the worker transferred, in kilobytes (KB).
• Slot — The total amount of information that the slot transferred, in megabytes (MB).
• Client — The IP address of the user who requested the data.
• VHost — The domain name of the server that requested the data.
• Request — The type of request that the server received.
  • GET — indicates that Apache downloaded data.
  • POST — indicates that Apache sent information to the server.

Apache dummy requests

Apache uses dummy requests to wake processes that listen for new connections. A dummy request is an HTTP request that Apache sends to itself. These requests, when Apache uses them without SSL, appear in access log files with the remote address set to the local host (127.0.0.1 for IPv4 or ::1 for IPv6). These dummy requests are a normal part of Apache’s functionality, which you can safely ignore.

Apache’s dummy requests cannot use SSL. It is possible that servers with hosts that use SSL can receive noise in the log file that resembles the following:

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[info] [client ::1] Connection to child 6 established (server localhost:443)
[info] Seeding PRNG with 656 bytes of entropy
[info] [client ::1] SSL library error 1 in handshake (server localhost:443)
[info] SSL Library Error: 336027900 error:140760FC:SSL routines:SSL23_GET_CLIENT_HELLO:unknown protocol speaking not SSL to HTTPS port!?
[info] [client ::1] Connection closed to child 6 with abortive shutdown (server localhost:443)

On a lightly loaded server, this interface frequently shows a high number of dummy connections. This occurs because the feature displays the last request to a worker slot, which is typically a dummy request.

It may also appear that Apache currently handles a high number of OPTIONS requests when in fact the workers are simply idle.