Preparations for backup

This topic describes how to configure the backup destination and the backup-related parameters.

Configure the backup destination

1. Log on to the sys tenant as the root user.

2. Configure the backup destination.

   OceanBase Database allows you to use Network File System (NFS) and Alibaba Cloud Object Storage Service (OSS) as the backup destination.

   For example:

   • NFS

     Notice

     When you use NFS as the backup destination, note the following points:

     • The string value of backup_dest cannot contain the question mark (?).
     • backup_dest must be set to an absolute value to ensure that the OBServer node has the write permission on the backup_dest.
     • Ensure that all OBServer nodes are mounted to NFS of the same server and use the parameter settings recommended in this topic. For more information about the procedure of mounting NFS, see Deploy the NFS client.
     • After you set the backup destination and enable backup, the backup files are stored in the directory named after the cluster. A backup destination can store backup files of different clusters. If the directory where the backup destination resides contains a directory with the same name as the cluster, this directory named after the cluster must be empty.

     Set the backup destination to NFS:

     obclient> ALTER SYSTEM SET backup_dest='file:///data/nfs/backup';
     

   • Alibaba Cloud OSS

     When you use OSS as the backup destination, you can set the backup destination and the delete_mode parameter to configure the backup file clearing mode.

     The delete_mode can be set to either of the following modes:

     • delete specifies that backup files that meet requirements are directly cleared.

       After you configure this mode, the system clears backup files that meet the requirements, regardless of whether the backup file clearing mode is automatic or manual. This is the default clearing mode. If you do not specify delete_mode, the default clearing mode delete is used.

     • tagging specifies that backup files that meet the clearing requirements are tagged and retained.

       After you configure this mode, the system tags backup files that meet the clearing requirements, regardless of whether the backup file clearing mode is automatic or manual. The key of the tag is set to delete_mode and the value is set to tagging. This way, you can manage the lifecycle of these files on OSS based on the specified tag.

     For more information about the operation of automatically clearing backup data, see Automatically clear backup data for clusters. For more information about the operation of manually clearing backup data, see Manually clear backup data for clusters.

     Set the backup destination and configure a backup file clearing mode:

     obclient> ALTER SYSTEM SET backup_dest='oss://oceanbase-test-bucket/backup/?host=xxx.aliyun-inc.com&access_id=xxx&access_key=xxx&delete_mode=delete';
     

     Notice

     • After you configure backup_dest and initiate a backup task, the value of the delete_mode parameter cannot be modified.
     • You must use the automatic backup expiration feature of OSS in conjunction with the delete_mode parameter of OceanBase Database.

   • Huawei Cloud OBS

     obclient> ALTER SYSTEM SET backup_dest='obs//oceanbase-test-appid/backup?host=obs.cn-east-2.myhuaweicloud.com&access_id=xxx&access_key=xxx';
     

After the backup destination is configured, the destination can be replaced only after you perform the following steps during backup and secondary backup tasks:

• Stop the backup task.

  For more information, see Stop a backup.

• (Recommended) Stop backup clearing.

  For more information, see Stop backup data clearing for clusters.

• Stop the secondary backup task.

  For more information, see Stop a secondary backup.

• (Recommended) Stop secondary backup clearing.

  For more information, see Stop secondary backup clearing.

(Optional) Configure backup parameters

1. Log on to the sys tenant as the root user.

2. Set the backup_dest_option parameter to configure backup-related parameters.

   The backup parameters include:

   • log_archive_checkpoint_interval

     The log_archive_checkpoint_interval parameter specifies the interval of generating log archive checkpoints for infrequently accessed partitions.

     Note

     Partitions with data writes are archived by clog. Infrequently accessed partitions do not have data writes. Therefore, log archive checkpoints are generated to facilitate log archiving for infrequently accessed partitions.

     If you do not specify this parameter for backup_dest_option, the value of the cluster-level log_archive_checkpoint_interval is used by default. If you do not specify either backup_dest_option or log_archive_checkpoint_interval, the default value 120s is used. If both backup_dest_option and log_archive_checkpoint_interval are specified, the value of backup_dest_option is used. We recommend that you set this parameter for backup_dest_option.

   • recovery_window

     The recovery_window parameter specifies the time window for restoring backup data. The system determines whether backup data has expired based on the value of this parameter. For example, the configuration recovery_window='7d' indicates that backup data within the last 7 days can be restored, and the backup data beyond this restore window is considered expired. For more information about the recovery_window parameter, see Automatically clear backup data for clusters.

     If you do not specify this parameter for backup_dest_option, the value of the cluster-level backup_recovery_window is used by default. If you do not specify either backup_dest_option or backup_recovery_window, the default value 0 is used, indicating that backup data will never expire. If both backup_dest_option and backup_recovery_window are specified, the value of backup_dest_option is used. We recommend that you set this parameter for backup_dest_option.

     When the backup expires, the system automatically clears it based on preset rules.

     In the manual clearing mode, when the backup data expires, you can manually clear the data as the administrator.

   • auto_delete_obsolete_backup

     The auto_delete_obsolete_backup parameter specifies whether to enable automatic data clearing. When you set auto_delete_obsolete_backup to true, the system automatically clears expired backup data.

     If you do not specify this parameter for backup_dest_option, the value of the cluster-level auto_delete_expired_backup is used by default. If you do not specify either backup_dest_option or auto_delete_expired_backup, the default value false is used, which indicates that expired backup data is not automatically cleared. If both backup_dest_option and auto_delete_expired_backup are specified, the value of backup_dest_option is used. We recommend that you set this parameter for backup_dest_option.

   • log_archive_piece_switch_interval

     The log_archive_piece_switch_interval parameter specifies whether to automatically split the log file directory into multiple directories based on a specific interval. Value range: [1d, 7d]. Default value: 0, which specifies not to perform log splitting.

     You must configure this parameter to enable log splitting.

   • backup_copies

     The backup_copies parameter specifies the number of backup copies. Default value: 0. If you do not specify backup_backup_dest, we recommend that you set backup_copies to 2. The valid value range of backup_copies is [0, 8].

     If you set backup_copies to a value less than 2, the system deletes backup data without considering whether its secondary backup is successful. If you set backup_copies to 2, the system will only automatically clear backup data in backup_dest after its secondary backup is saved to backup_backup_dest. If secondary backup is not set, we recommend that you use the default value.

   For more information about the backup_dest_option parameter, see backup_dest_option.

   Here is an example:

   obclient> ALTER SYSTEM SET backup_dest_option='log_archive_checkpoint_interval=2m&recovery_window=7d&auto_delete_obsolete_backup=true&log_archive_piece_switch_interval=1d&backup_copies=0';