This morning, the computer that hosts my Web-site received a routine update to its PHP 5 interpreter – i.e. to some of the modules of its PHP 5 system – which also triggered a routine restart of the Apache server processes. This has taken place without causing the slightest disruption to my site.
What most Linux-based services do, during a log-rotation, is also to restart, so that after the log-files have been renamed, the services obtain a new file-handle as well, and so that the actual writing of log data resumes with a newly-created log-file. Apache tends to be atypical, in that one of its available commands is to reload its configuration and/or its log-files. Thus, usually, the main Apache service just keeps running.
Technically, this morning, the Apache server was gone for two seconds. But, if an average reader was to find that this interfered with his browsing, he would have been able to fix that, just by clicking on the same URL a second time.
Also, my blog consists of PHP scripts, which every HTTP request executes independently of the other requests. Persistence is achieved by browser-scripts, and by a MySQL database which the server-scripts access. So there is also no loss of persistence, of my site, arising from an Apache server restart.