The server log stores information on access to your site, as well as all script execution actions. The magazine is useful for analyzing the site for errors in the execution of certain scripts. For example, to view errors, you must open a file with the error prefix, while a file with general information will have the access prefix. Analysis of these files will reveal what exactly the site is working wrong and find out for what reason.
As we see in the screenshot, the old logs have the gz prefix at the end - this means that they are packed by the archiver to save space. If necessary, they can be unzipped. Old log files (logs) are deleted automatically in exchange for new ones. For online view log see.