fail2ban excessive write amplification of sqlite

[JorSol]

I use Ubuntu 16.04 LTS on a mail server with many users and configured fail2ban to reject spammers and attackers.

When the server is under load fail2ban has high cpu usage, but most notably a high write to disk.

This inherently slows the system and put high stress to disks, trying to find the cause I found this mailing list thread: https://sourceforge.net/p/fail2ban/mailman/message/35961119/ on which SSD suffers the pain of this write amplification caused by sqlite database, this is a major trouble for SSD, but any system is hit by the performance degradation.

The fix can be found on https://github.com/fail2ban/fail2ban/pull/1436/files and since Ubuntu 16.04 will be supported until 2021, this should be back-ported.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.