Logging in Litespeed

Although we don't like to think about our backups and restores going wrong, there are times when things just sometimes don't work as planned, and if it's not something that is easy to troubleshoot, you may find yourself raising a support case to help fix the issue.

One of the things that is most helpful to assist with troubleshooting, is an 'Advanced Engine Log'. This is a verbose log file, which when enabled, is created in the background and captures all the tasks Litespeed is performing, and any errors which may be appearing.

Enabling Litespeed Logging

It is a very simple process to enable logging, but as logging produces additional overhead, it is recommended to only turn on Litespeed logging when required in your support case. Otherwise, the disk may end up filling up with un-needed logs!

Firstly, right-click the registered server you need to produce the log files for, and choose the option 'Support | Litespeed Logging'

You will see the following screen, which has a range of options to choose from:

It's important that the 'Core Engine' box is selected, as this is the setting which turns on the Advanced Engine Logs.
Additional log files can be generated for certain other modules in Litespeed too.

Make a note of the Log File Path as this is where the files will be stored. The location in the screenshot above is the default location, but you can adjust this to the most convenient location.

To quickly explain some of the other options here:

  • Flush output to log file after every write (slower) - Select this option if you have program exceptions resulting a process being aborted.
  • Delete log file on success - A log file is only saved if an error has occurred during execution. This can be useful in narrowing down log file creation!
  • Log rollover size - This will limit the size of the log file, so that only the last records that fit within the specified size will be kept. This can be useful if it's a long running application, when the log file becomes overly large, or when an error happens near the end of an execution. Otherwise, set the rollover size value to zero.

Once selected, replicate the error you are having and this time the error will be recorded in a log file, saved in the 'Log File Path' location, set in the screenshot above.


The Engine log files all begin with SLS and then the date and time, so they are easy to determine, and these are the ones which contain the details.

When you have the logs, please once again disable logging in the 'Support | Litespeed Logging' menu.

Learn more about SQL Server backup, compression and restore.

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