Historical Logs

Refer below

https://support.f5.com/csp/article/K16197

cat /var/log/ltm | grep nodeip
cat /var/log/ltm | grep poolname
zcat ltm.1.gz | grep input, input may be nodeip, vipip, pool name etc or
zcat ltm.*.gz | grep input, input may be nodeip, vipip, pool name etc or

If you are using gtm use gtm instead of ltm in above commands

A better way to verify log is CLI or move logs to log server eg: Splunk,qradar or other SIEM solutions etc..

HTH