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KBA1622 Delphix and MySQL


Q:Why is the MySQL VDB not started using the mysqld_safe script (using the mysqld_safe script is the recommended way to start mysql)?

The main benefit mysqld_safe provides is auto-restarting the server if it crashes. For staging instances, Delphix manages restarting the instance if it crashes and also checks for errors that could compromise the validity of the data. For VDBs, we want to notify the user if a crash happens, so we monitor the database and raise a fault if it goes down.

Q: Is there any difference in shutting down mysql manually versus from Delphix?

We recommend to shutdown and restart the VDBs from Delphix console. Performing this action from Delphix leaves the system in an expected state (NFS drives are mounted or unmounted for example). For V2Ps, you can manually do it yourself.

Q: Can we provision a physical database by leveraging the Delphix feature of converting a VDB to a physical/standalone database?

Yes, you can use the virtual to physical (V2P) feature, to convert a VDB to a physical, standalone MySQL Server instance. V2P still requires a MySQL binary installation (rpm) as a separate step which is external to Delphix V2P provisioning. Using a tool like Puppet or Chef is currently the easiest way to orchestrate the binary installation of MySQL.

Q: Why aren't the mount points for MySQL consistent with the Oracle version of Delphix?

Oracle is inconsistent with the rest of the database platform support. MySQL follows the design pattern of SAP ASE and PostgreSQL.

Q: Is possible to customize/edit the my.cnf that gets created during provisioning without having to modify it manually afterwards?

You can add or edit MySQL configuration parameters using the advanced feature on the provisioning wizard when you provision a VDB or V2P.

Q: When hosting multiple mysql virtual instances on a target server, what is the best way to distinguish which data directory belongs to the specific instance?

MySQL doesn’t have the concept of ORACLE_SID so what we have been doing is to use the PORT number to distinguish the multiple instances. For each instance you can check its defaults-file to get the data file path, and create a symbolic link according to your standard.