How can I find older logs in ltm through CLI in a specific partition

zcat

is your friend.

All log files are stored in /var/log

Generally, logs are rotated after 24 hours.

for the ltm log file

ltm is todays log file

ltm.1 is yesterdays file, and is not compressed

ltm.2.gz is from the day before that, and is gz compressed.

zcat ltm* | grep 

will search all the available ltm log files (including the compressed ones) for your search string.

If you are logging too much information (usually from iRule log messages) the logs will be rotated when they get too big. By default, the LTM retains 10 older files - this can be increased to 30.

Our recommendation is that if you require significant logging and log retention/search/reporting, you should consider remote syslog logging via the network to something like Splunk or Arcsight. The LTM is not optimised for disk I/O and excessive logging can negatively impact performance.

K13367: Managing log files on the BIG-IP system (11.x - 13.x)