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This change adds new options for controlling the SST using the mariabackup method, which in many cases will allow much more effective management of the free space used during the SST process. Two new options have been added, which can be used in the configuration file by placing them in the [sst] section: 1) The 'sstdir' option sets the path to the temporary directory where the received files will be placed during the state transfer process in SST using mariabackup. Before this change, files were always written to a special directory <datadir>/.sst, which created a problem if the storage where datadir resides was close to full. Now, however, it is possible to specify an arbitrary directory where the system will place the files received during SST. Attention! The directory specified with sstdir will be deleted during the SST process – therefore, it cannot be the datadir itself or any important user directory containing valuable files! It must be a working temporary directory that will be automatically removed by the system at the end of SST. The user can also set the special value sstdir='mktemp'. In this case, the system will automatically create a working directory for SST using the mktemp utility (possibly using the tmpdir directory if it is specified in the configuration file). This directory will be deleted after the SST is completed. 2) The 'cleaning' option allows controlling the timing of the deletion of the current system state when SST is required. Currently, as well as by default after this change, the current state is deleted in parallel with the transfer of new data during SST. This is optimal in terms of performance but may cause problems if the storage where datadir resides has little free space and the same storage is used for receiving files – because the old files are not deleted immediately, but only after some time. If the user is interested in deleting the current state before the start of SST, which allows freeing up space on the datadir storage, they can now set the option cleaning='before', and the current state will be deleted before SST starts. This may be slower in terms of performance but frees up space, which can be critical in some user scenarios. On the other hand, the user can specify cleaning='after' – in this case, the current state will be deleted only after the successful completion of data transfer during SST. This reduces performance and requires more free space but guarantees that the current state will not be deleted on the node before the successful completion of data transfer – which can critically increase reliability in user scenarios where loss of state on nodes due to a chain of failures during SST transfer creates a risk of cluster degradation. If the user specifies cleaning='parallel' or does not set any value for this option, the system will operate as before – deleting the current state in parallel with receiving new data. This maximizes performance but requires large amounts of free space in the location specified by sstdir and may result in the loss of node state if data transfer during SST fails. |
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| .. | ||
| include | ||
| r | ||
| t | ||
| disabled.def | ||
| galera_2nodes.cnf | ||
| galera_2nodes_as_master.cnf | ||
| galera_2nodes_as_replica_2primary.cnf | ||
| galera_2nodes_as_slave.cnf | ||
| galera_2x2nodes.cnf | ||
| galera_3nodes_as_slave.cnf | ||
| galera_4nodes.cnf | ||
| my.cnf | ||
| suite.pm | ||