Thread:Project:Support desk/Won't Access Database: Too many open links/reply

If this is about the number of DB connections, which MediaWiki needs to open, then this depends on the number of concurrent visitors to your wiki. You might start with something like 25 and go higher, should you need more.

Which versions of PHP and MySQL are you using? PHP before 5.3.3 had a bug[1] which made it create "zombie connections". These then slowly filled up ressources until the DB was no longer reachable.

[1] https://bugs.php.net/bug.php?id=51605