Today I’ve updated MySQL server on one of my Ubuntu 12.04 servers. After the upgrade finished, shock and horror: all websites were down, WordPress sites were presenting install page. Quickly connected to mysql via CLI and tried to see if the databases are still there:
mysql> show databases; ERROR 1018 (HY000): Can't read dir of '.' (errno: 24)
I’ve tried setting limits as in this article, but that didn’t seem to help. Only after adding “open-files-limit = 2048” to my.cnf and restarting the MySQL server things went back to normal. So a big thank you to the author of the article, but I would like to know if there is any need setting those limits or not(obviously I was stressed out over the web sites being down and didn’t test all things).
Anyone else has any experience with this problem?