maria-discuss team mailing list archive

[Craig Bailey <cbailey@xxxxxxxxxx>]

Hi,

I am attempting to get remote replication working from my MariaDB Galera Cluster in the following way:

*         MariaDB Galera Cluster replicates to a remote MariaDB DR node via standard master slave method using MariaDB GTID

o   Pick a master node from the cluster

o   Take a backup with xtrabackup-v2

o   Apply backup to slave

o   Connect the slave to the master and replicate using MariaDB GTID

o   If master goes down, switch master to another node in the Galera Clutser


However I am having problems keeping the GTID in step across all the nodes in the Galera cluster when joining new nodes or re-joining existing nodes.

Using the latest version of xtrabackup-v2 the current GTID position is stored in a file as part of the backup, however it does not apply this value to the database when a node is brought into the cluster. A step by step example is below:

*         Cluster is running fine

*         Lots of transactions going through, enough that a new joiner would need an SST

*         Begin joining a new node to the cluster

*         SST via xtrabackup-v2 happens during this process

*         The GTID in the donor is 1-1-12345

*         SST completes joiner is now part of the cluster

*         The GTID on the newly joined node is 1-1-1

*         We now have an out of sync GTID meaning we cannot simply switch master if our current master goes down.

I tried the same scenario using RSYNC as the transfer method and the GTID is replicated across to the joiner without issue.

Ideally I would like continue using xtrabackup-V2 as my SST method because it does very little locking on a state transfer. That being the case are there any work arounds for this, such as a way to ensure the GTID is set on the joiner when the SST happens with xtrabackup-v2?
On the MariaDB pages it does say "xtrabackup-v2  and xtrabackup SST methods currently do not support GTID" is this up-to-date information? https://mariadb.com/kb/en/mariadb/galera-cluster-system-variables/#wsrep_sst_method

Thanks,
Craig

Evertz UK

cbailey@xxxxxxxxxx<mailto:cbailey@xxxxxxxxxx>

www.evertz.com

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