Percona XtraDB Cluster 8.0 (experimental release) : SST Improvements

xtradb sst improvementsStarting with the experimental release of Percona XtraDB Cluster 8.0, we have made changes to the SST process to make the process more robust and easier to use.

  • mysqldump and rsync are no longer supported SST methods.

    Support for mysqldump was deprecated starting with PXC 5.7 and has now been completely removed.

    MySQL 8.0 introduced a new Redo Log format that limited the use of rsync while upgrading from PXC 5.7 to 8.0. In addition, the new Galera-4 also introduced changes that further limits the use of rsync.

    The only supported SST method is xtrabackup-v2.

  • A separate Percona XtraBackup installation is no longer required.

    The required Percona XtraBackup (PXB) binaries are now shipped as part of PXC 8.0, they are not installed for general use. So if you want to use PXB outside of an SST, you will have to install PXB separately.

  • SST logging now uses MySQL error logging

    Previously, the SST script would write directly to the error log file. Now, the SST script uses MySQL error logging. A side effect of this change is that the SST logs are not immediately visible. This is due to the logging subsystem being initialized after the SST has completed.

  • The wsrep_sst_auth variable has been removed.

    PXC 8.0 now creates an internal user (mysql.pxc.sst.user) with a random password for use by PXB to take the backup. The cleartext of the password is not saved and the user is deleted after the SST has completed.

    (This feature is still in development and may change before PXC 8.0 GA)

  • PXC SST auto-upgrade

    When PXC 8.0 detects that the SST came from a lower version, mysql_upgrade is automatically invoked. Also “RESET SLAVE ALL” is run on the new node if needed. This is invoked when receiving an SST from PXC 5.7 and PXC 8.0.

    (This feature is still in development and may change before PXC 8.0 GA)

Help us improve our software quality by reporting any bugs you encounter using our bug tracking system. As always, thanks for your continued support of Percona!

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