How to spend MORE time? Tips for sysadmins of all ages.

It often happens that despite doing everything right it just doesn't work. After hours of investigating you finally find a reason for this - a minor typo or a footnote in the manual... Well, it is especially awful when you make the same mistake again, so I decided to make a list of a few personal failures of this sort, mostly to remember myself what I did wrong.

• Setting up PHP as a FastCGI wrapper in Apache 2.2.x with mod_fcgid is rather straightforward. However it is often (in my case, twice) overlooked that mod_fcgid imposes a request body length limitation on its own with FcgidMaxRequestLen directive. So, when you are asked to increase maximum uploaded file you need to adjust this setting as well as PHP's post_max_size and upload_max_filesize settings.
• Generally, beware of additional limits imposed by mod_fcgid. Recently tripped over its FcgidIOTimeout default of 40 seconds. Well, the limit is rather reasonable but PHP developers often are not, and when setting max_execution_time remember to set FcgidIOTimeout a bit higher as well.
• Same applies to PHP-FPM under Nginx, I forgot about client_max_body_size more than once.
• Setting up IPsec with StrongSWAN is not very intuitive, and infamous no matching peer config found may make you really mad. Most often it is due to bad rightid/leftid specification — if you give none some random-looking default would be used. So you are to give this ID explicitly, and if you give bad CommonName you can easily miss the corresponding error message. Yesterday I've spent another half an hour because of erroneous /L=MyCity/ inclusion - everything else was correct.
• 19 Oct 2017 A fellow developer spent a few hours trying to resolve an "Access denied" error from MySQL. I suspected a few advanced things - like PHP's mysqlnd driver incompatibility with Amazon Aurora, but after we tried a minimal test case (mysql_connect() instead of intricate Doctrine ORM-powered process) he finally found out that they had a '$' sign in the password which got interpolated as a variable substitution. Funny thing, isn't it? So, remember, when it comes to passwords (and, frankly, other things from outside world) - '...'-quoted strings are your friends and double quotes are evil.