Database (Percona/MySQL)

The DB layer on a BOA host is Percona Server, version-pinned per Devuan codename, with one shared server instance per host serving every Octopus instance, the Hostmaster front end, and every hosted site.

This section documents the operating interface:

• how the server is installed and tuned
• how /etc/mysql/my.cnf is deployed and protected
• the nightly mydumper dump chain
• the browser DB tools and their access model
• the graceful stop/start orchestrator the upgrade and self-heal paths drive

Everything here is keyed to the live source:

• lib/functions/sql.sh.inc (install, the my.cnf template lifecycle, InnoDB sizing, the upgrade-time memory tuner)
• the per-DB dump scripts under aegir/tools/system/
• the monitor/check/mysql.sh self-heal path
• the xtra.sh.inc GUI-tool installers

Two things the names suggest but the code does not do are called out explicitly:

• mycnfup is not the version migrator
• move_sql.sh does not move databases

The architectural shape worth holding in mind:

• One server, host-wide. A single Percona daemon, one my.cnf, one slow log, one set of binlogs. There is no per-Octopus DB split — per-instance separation is by user/database grants, not by socket or config.
• The my.cnf is template-deployed, not generated. BOA copies aegir/conf/var/my.cnf.txt over /etc/mysql/my.cnf and sed-patches a handful of directives per Percona series. No per-host generation, no marker diff. _CUSTOM_CONFIG_SQL=YES is the only thing that stops the re-deploy.
• Credentials never hit the command line. Every BOA-issued MySQL command authenticates via --defaults-file=/root/.my.cnf (or the implicit root read), so the root password never lands in /proc/<pid>/cmdline.

The pages below cover Percona install and tuning, the my.cnf lifecycle, the nightly mydumper dump chain, the browser DB tools, the graceful stop/start orchestrator, and the Percona 8 upgrade-readiness check.

See the Reference appendix for the consolidated _VAR and command tables, and Discontinued features for the dropped Simple Cluster (Percona XtraDB Cluster + ProxySQL + Galera) and Chive.