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State snapshot transfer
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      • Release notes index
      • Percona XtraDB Cluster 8.0.34-26 (2023-11-01)
      • Percona XtraDB Cluster 8.0.33-25 Update (2023-08-25)
      • Percona XtraDB Cluster 8.0.33-25 (2023-08-02)
      • Percona XtraDB Cluster 8.0.32-24.2 (2023-05-24)
      • Percona XtraDB Cluster 8.0.32-24 (2023-04-18)
      • Percona XtraDB Cluster 8.0.31-23.2 (2023-04-04)
      • Percona XtraDB Cluster 8.0.31-23 (2023-03-14)
      • Percona XtraDB Cluster 8.0.30-22.md (2022-12-28)
      • Percona XtraDB Cluster 8.0.29-21 (2022-09-12)
      • Percona XtraDB Cluster 8.0.28-19.1 (2022-07-19)
      • Percona XtraDB Cluster 8.0.27-18.1
      • Percona XtraDB Cluster 8.0.26-16.1
      • Percona XtraDB Cluster 8.0.25-15.1
      • Percona XtraDB Cluster 8.0.23-14.1
      • Percona XtraDB Cluster 8.0.22-13.1
      • Percona XtraDB Cluster 8.0.21-12.1
      • Percona XtraDB Cluster 8.0.20-11
      • Percona XtraDB Cluster 8.0.20-11.3
      • Percona XtraDB Cluster 8.0.20-11.2
      • Percona XtraDB Cluster 8.0.19-10
      • Percona XtraDB Cluster 8.0.18-9.3
      • About Percona XtraDB Cluster
      • Percona XtraDB Cluster limitations
      • Understand version numbers
      • High availability
      • Percona XtraDB Cluster strict mode
      • Online schema upgrade
      • Non-Blocking Operations (NBO) method for Online Scheme Upgrades (OSU)
      • Quickstart Guide for Percona XtraDB Cluster
      • Get started with Percona XtraDB Cluster
      • Install Percona XtraDB Cluster
      • Install Percona XtraDB Cluster on Debian or Ubuntu
      • Install Percona XtraDB Cluster on Red Hat Enterprise Linux and CentOS
      • Install Percona XtraDB Cluster from Binary Tarball
      • Compile and install from Source Code
      • Running Percona XtraDB Cluster in a Docker Container
      • Configure nodes for write-set replication
      • Bootstrap the first node
      • Add nodes to cluster
      • Verify replication
      • Upgrade Percona XtraDB Cluster
      • Restore a 5.7 backup to an 8.0 cluster
      • Security basics
      • Secure the network
      • Encrypt PXC traffic
      • Enable AppArmor
      • Enable SELinux
      • State snapshot transfer
        • Choose the SST Donor
        • Use Percona Xtrabackup
        • SST for tables with tablespaces that are not in the data directory
          • SST using Percona XtraBackup
        • Other reading
      • Percona XtraBackup SST configuration
      • Restart the cluster nodes
      • Cluster failover
      • Monitor the cluster
      • Certification in Percona XtraDB Cluster
      • Percona XtraDB Cluster threading model
      • Understand GCache and Record-Set cache
      • GCache encryption and Write-Set cache encryption
      • Perfomance Schema instrumentation
      • Data at Rest Encryption
      • Crash recovery
      • Configure a cluster on Red Hat-based distributions
      • Configure a cluster on Debian or Ubuntu
      • Set up Galera arbitrator
      • How to set up a three-node cluster on a single box
      • How to set up a three-node cluster in EC2 environment
      • Load balancing with HAProxy
      • Load balance with ProxySQL
      • ProxySQL admin utilities
      • Set up a testing environment with ProxySQL
      • Index of wsrep status variables
      • Index of wsrep system variables
      • Index of wsrep_provider options
      • Index of files created by PXC
      • Telemetry on Percona XtraDB Cluster
      • Frequently asked questions
      • Glossary
      • Copyright and licensing information
      • Trademark policy

    • Choose the SST Donor
    • Use Percona Xtrabackup
    • SST for tables with tablespaces that are not in the data directory
      • SST using Percona XtraBackup
    • Other reading

    State snapshot transfer¶

    State Snapshot Transfer (SST) is a full data copy from one node (donor) to the joining node (joiner). It’s used when a new node joins the cluster. In order to be synchronized with the cluster, the new node has to receive data from a node that is already part of the cluster.

    Percona XtraDB Cluster enables via xtrabackup.

    Xtrabackup SST uses backup locks, which means the Galera provider is not paused at all as with earlier. The SST method can be configured using the wsrep_sst_method variable.

    Note

    If the gcs.sync_donor variable is set to Yes (default is No), the whole cluster will get blocked if the donor is blocked by SST.

    Choose the SST Donor¶

    If there are no nodes available that can safely perform incremental state transfer (IST), the cluster defaults to SST.

    If there are nodes available that can perform IST, the cluster prefers a local node over remote nodes to serve as the donor.

    If there are no local nodes available that can perform IST, the cluster chooses a remote node to serve as the donor.

    If there are several local and remote nodes that can perform IST, the cluster chooses the node with the highest seqno to serve as the donor.

    Use Percona Xtrabackup¶

    The default SST method is xtrabackup-v2 which uses Percona XtraBackup. This is the least blocking method that leverages backup locks. XtraBackup is run locally on the donor node.

    The datadir needs to be specified in the server configuration file my.cnf, otherwise the transfer process will fail.

    Detailed information on this method is provided in Percona XtraBackup SST Configuration documentation.

    SST for tables with tablespaces that are not in the data directory¶

    For example:

    CREATE TABLE t1 (c1 INT PRIMARY KEY) DATA DIRECTORY = '/alternative/directory';
    

    SST using Percona XtraBackup¶

    XtraBackup will restore the table to the same location on the joiner node. If the target directory does not exist, it will be created. If the target file already exists, an error will be returned, because XtraBackup cannot clear tablespaces not in the data directory.

    Other reading¶

    • State Snapshot Transfer Methods for MySQL

    • Xtrabackup SST configuration

    Contact us

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    Last update: 2023-07-21
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