Configuring and Viewing Persistent Logging Storage

The device automatically saves logged system event messages in its storage memory, where they persist even if the device restarts or powers off. Persistent logging is done by default (and cannot be disabled). Persistent logging eliminates the need for sending logged messages to third-party, logging servers (such as a syslog server) and provides an efficient tool for troubleshooting the device.

When the device operates in HA mode, Persistent Logging storage is not copied to the Redundant device upon an HA switchover.

The device can store up to 10 (#0-9) persistent log files, where #0 is the latest file and #9 the oldest. A new file (log rotation) is created (and the oldest file is deleted) when one of the following events occur first:

The maximum size (in KB) of the file is reached (default is 1,024 KB). The maximum file size is configured using the 'Persistent Log Size' parameter [SystemPersistentLogSize] on the Logging Settings page (Troubleshoot menu > Troubleshoot tab > Logging folder > Logging Settings).
The age of the file (in minutes) is reached (default is unlimited). The file age is configured using the 'Persistent Log Period' parameter [SystemPersistentLogPeriod] on the Logging Settings page (Troubleshoot menu > Troubleshoot tab > Logging folder > Logging Settings).

New messages are added to a temporary "current" file and when the file size reaches the maximum or the age of the file is reached (whichever occurs first), the file becomes #0 and the index number of each of the older files is incremented. For example, the previous file #0 becomes #1, #1 becomes #2, and so on. When the device's persistent logging storage is full (i.e., 10 files have been created) and a new file (#0) is created from the "current" file with the new logged messages, the index number of the older files are incremented as explained previously, but the oldest file (#9), which is replaced by #8, is deleted from storage.

If you want to protect personal information, it's recommended to configure the 'Persistent Log Period' parameter to any value other than 0. This ensures that the log files are not stored indefinitely and that they are always being replaced every user-defined period (even if empty).

To view a specific persistent log file (0 is latest):
show system log persistent <0-9>