Wiki: iRules API

High Speed Logging



These commands allow you to send data to a pool of servers via High Speed Logging. High Speed Logging was designed to be a high volume, low overhead logging mechanism. HSL supports logging via TCP or UDP. Informal testing has shown CPU and memory utilization for HSL to be very low (<10% CPU, almost no additional memory utilization).

For example, you could use these commands to:

  • Log all HTTP requests and responses processed via the LTM by sending the data to a pool of remote servers.
  • Log the SSL cipher name, version, size for each SSL session before restricting ciphers
  • Log every load balancing failure (not just a member failing a monitor)
  • Supplement or replace tcpdump for troubleshooting layer 7 issues (it can be much easier to log the decrypted content rather than decrypting SSL with ssldump, etc)

Note that HSL requires the use of the TMM routes and a route must be in place to send HSL traffic via switch port interfaces. Routing via the management interface is not supported and will not work.
Will work in version 12.0 and later ref.:

Command List

  • HSL::open - Open a handle for High Speed Logging communication
  • HSL::send - Send data via High Speed Logging

  • Introduced: BIGIP-10.1.0