how long can store log in switch local storage

[MrBeginner]

hi,

i would like to know about how long can switch local storage keep log ?

what kind of log are store in switch local storage ?

if switch is restart what kind of log are still remain in switch storage ?

In the operation what kind of log are need to store for troubleshooting purpose ?

[marce1000]

 - Take note of this thread and or also consider using a syslog server for keeping logs :

          https://community.cisco.com/t5/switching/cisco-switch-logging-buffer-size/td-p/3299430

 M.

[balaji.bandi]

Switch Log stored in Buffer based on the available and first come last will go will be the basis. if the Switch rebooted the logs go you do not have any more logs - advise you to set up a Syslog server to offload from the switch, you can retain as long as you want for governance and diagnosis purpose.

[Joseph W. Doherty · Accepted solution]

"i would like to know about how long can switch local storage keep log ?"

As long as 1) there's no power interruption and 2) the log space isn't filled.

"what kind of log are store in switch local storage ?"

Syslog, if enabled to do so. Content depends on logging detail settings and what event transpire on the device.

"If switch is restart what kind of log are still remain in switch storage ?"

None, although some failure restarts will log some reason for restart and perhaps a diagnostic dump into flash too.

"In the operation what kind of log are need to store for troubleshooting purpose ?"

Unfortunately, often not enough information on the device, itself, to troubleshoot. As the other posters have noted, you can direct syslog to an external syslogging device, and that might provide the information needed right before the device failed. However, as mentioned above, you can control what information might be logged so, without the "needed" settings, you might not have enough detail information to determine cause of issue.