If you are running AOS 5.10.9 or below or AOS 5.11.1 and thinking of upgrading or have already scheduled one there is on thing to consider prior to executing the task.
Check the size of localhost_access_log.txt file. If it has grown out of proportion (several GB) then you may want to clear it first and, if you can, chose AOS 5.10.10 or later, AOS 5.16.1 or AOS 5.17 or later as an upgrade target.
Otherwise you may find some issues with the upgrade.
Save yourself some hassle and see the details in the KB-8561 Prism Central/Prism Element upgrade failing with /home space constraints due to localhost_access_log.txt files not rotating