Can sst_state_transfer be set to rsync with innodb as storage engine in Galera cluster? Galera cluster wsrep-sst-method docs states:


  You can only use rsync when anode is starting. You cannot use it with
  a running InnoDB storage engine.


I do have InnoDB storage engine configured in MariaDB Galera cluster and the wsrep-sst-method is set to rsync and state transfers do happen on starting nodes.

What's wrong with this configuration? Is xtrabackup the only wsrep-sst-method to be used with innodb storage engine?
Is xtrabackup the only wsrep-sst-method to be used with innodb storage engine?


All Galera clusters are InnoDB, MyISAM (and derivates) not supported (expect mysql database with wrappers for managing users/permissions).

No, nothing wrong with your configuration. You can use Logical State Snapshot mysqldump or the Physical State Snapshot rsync and xtrabackup. See State Snapshot Transfers for a comparison.

A physical restore always needs a restart. The same concept like backup/restore.

In normal operations only IST is needed. SST is only needed when something goes wrong (maybe infrastructure issue) and the node is out-of-sync. Mostly the DBA cares about such cases.


State Snapshot Transfers (SST) Where a snapshot of the entire node
state transfers.
Incremental State Transfers (IST) Where only the missing transactions transfer.