Preparations

This topic describes the preparations for log archiving.

(Optional) Configure the log archiving concurrency

Before you enable the ARCHIVELOG mode for a tenant, you can configure the log archiving concurrency to accelerate log archiving for the tenant.

1. Log on to the database as an administrator of the sys tenant or a user tenant.

2. Configure the log_archive_concurrency parameter by using a proper statement.

   The tenant-level parameter log_archive_concurrency specifies the total number of worker threads for log archiving. The modification of this parameter takes effect immediately without restarting the OBServer node. The value range of this parameter is [0, 100]. The default value is 0, which means using the adaptive log archiving concurrency of OceanBase Database. We recommend that you use the default value.

   Notice

   If the tenant is configured with two or four CPU cores, we recommend that you retain the default value of this parameter.

   Methods for adjusting the log archiving concurrency are as follows:

   • Execute the following statement in the sys tenant to adjust the log archiving concurrency of a specified tenant:

     ALTER SYSTEM SET log_archive_concurrency = 10 TENANT = mysql_tenant;
     

   • Execute the following statement in the sys tenant to adjust the log archiving concurrency of all tenants:

     ALTER SYSTEM SET log_archive_concurrency = 10 TENANT = ALL;
     

   • Execute the following statement in a user tenant to adjust its log archiving concurrency:

     ALTER SYSTEM SET log_archive_concurrency = 10;
     

   For more information about the log_archive_concurrency parameter, see log_archive_concurrency.

Configure the archive destination

Before you initiate a log archiving job, you must execute the ALTER SYSTEM statement to configure the LOG_ARCHIVE_DEST parameter. The sys tenant is used for managing clusters and does not contain user data or support backup or restore. Therefore, you do not need to configure an archive destination for the sys tenant.

Set the LOCATION, PIECE_SWITCH_INTERVAL, and BINDING attributes of the archive destination.

1. Log on to the database as an administrator of the sys tenant or a user tenant.

   Note

   The administrator user of a MySQL tenant is root and that of an Oracle tenant is SYS.

2. Configure the archive destination.

   At present, OceanBase Database allows you to select Network File System (NFS) or Alibaba Cloud Object Storage Service (OSS) as the archive destination.

   • Configure the archive destination for a specified tenant in the sys tenant:

     ALTER SYSTEM SET LOG_ARCHIVE_DEST='LOCATION=xxx [PIECE_SWITCH_INTERVAL=xxx] [BINDING=xxx]' TENANT = tenant_name;
     

   • Configure the archive destination for a user tenant from the current tenant:

     ALTER SYSTEM SET LOG_ARCHIVE_DEST='LOCATION=xxx [PIECE_SWITCH_INTERVAL=xxx] [BINDING=xxx]';
     

   Notice

   After upgrading OceanBase Database from V4.0.x to V4.1.0, it is necessary to change the archive path. However, when upgrading from V4.1.x to V4.2.0, there is no need to modify the archive path. Moreover, during the upgrade process from V4.1.x to V4.2.0, you have the option to archive logs.

   You can query the CDB_OB_ARCHIVE_DEST view from the sys tenant or the DBA_OB_ARCHIVE_DEST view from a user tenant for the settings. For more information, see View the archiving parameter settings.

   The procedure is as follows:

   • (Required) Set LOCATION.

     The LOCATION attribute specifies the archive destination. OceanBase Database supports two types of media as the archive destination: Network File System (NFS) and Alibaba Cloud Object Storage Service (OSS).

     • NFS

       Notice

       When you use NFS as the archive destination, note that:

       • The value of LOCATION cannot be a string with a question mark (?).
       • The value of LOCATION must be an absolute path, and the OBServer node must have read and write privileges on the destination specified by LOCATION.
       • 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 deploying NFS, see Deploy NFS.

       To set NFS as the archive destination, execute the following statement:

       ALTER SYSTEM SET LOG_ARCHIVE_DEST='LOCATION=file:///data/nfs/backup/archive' TENANT = mysql_tenant;
       

       ALTER SYSTEM SET LOG_ARCHIVE_DEST='LOCATION=file:///data/nfs/backup/archive';
       

       In this example, file:// specifies that NFS is used as the media for the archive destination, and the archive path is /data/nfs/backup/archive.

     • OSS

       When you use OSS as the archive destination, besides the archive path and the host, access_key, and access_id parameters, you can also set the delete_mode parameter to configure the cleanup mode for archived files.

       The delete_mode parameter has two values: delete and tagging. If you do not specify this parameter, the default value delete takes effect.

       • delete: Archived files that meet the cleanup requirements are directly deleted.

         In this mode, when you enable automatic cleanup for archived files in automatic mode, the system directly deletes the archived files that meet the requirements.

         Notice

         This is the default cleanup mode. If you do not specify delete_mode, the default cleanup mode delete takes effect.

       • tagging: The archived files that meet the cleanup requirements are tagged and retained.

         In this mode, when you enable automatic cleanup for archived files, the system directly tags the archived files that meet the cleanup requirements. The key of the tag is delete_mode and the value is tagging. In this way, you can manage the lifecycle of these files on OSS based on the tags.

       For more information about the automatic cleanup of archived data in delete or tagging mode, see Automatic cleanup of archived data.

       To set OSS as the archive destination and configure the tagging cleanup mode, execute the following statement:

       ALTER SYSTEM SET LOG_ARCHIVE_DEST='LOCATION=oss://oceanbase-test-bucket/backup/archive?host=xxx.aliyun-inc.com&access_id=xxx&access_key=xxx&delete_mode=tagging' TENANT = mysql_tenant;
       

       ALTER SYSTEM SET LOG_ARCHIVE_DEST='LOCATION=oss://oceanbase-test-bucket/backup/archive?host=xxx.aliyun-inc.com&access_id=xxx&access_key=xxx&delete_mode=tagging';
       

       In this example, oss:// specifies that OSS is the archive destination. The storage bucket is named oceanbase-test-bucket. The path in the storage bucket is /backup/archive. The question mark (?) is used to separate other parameters of the path. The host parameter specifies the host address of the storage bucket. The access_id and access_key parameters specify the access key of OSS. The cleanup mode is set to tagging.

   • (Optional) Set the BINDING attribute.

     The BINDING attribute specifies the prioritizing mode for archiving and businesses. The BINDING attribute has two values: Optional and Mandatory. If you do not specify this attribute, the default value Optional takes effect.

     • The Optional mode prioritizes user businesses. In this mode, when log archiving falls behind log generation, logs may be recycled before being archived. This causes an interruption.

     • The Mandatory mode prioritizes archiving. In this mode, you may be unable to write more data before existing data is archived.

     Here is an example:

     ALTER SYSTEM SET LOG_ARCHIVE_DEST='LOCATION=file:///data/nfs/backup/archive BINDING = Optional' TENANT = mysql_tenant;
     

     ALTER SYSTEM SET LOG_ARCHIVE_DEST='LOCATION=file:///data/nfs/backup/archive BINDING = Optional';
     

   • (Optional) Set the PIECE_SWITCH_INTERVAL attribute.

     The PIECE_SWITCH_INTERVAL attribute specifies the switching interval for pieces. The value range is [1d, 7d]. If you do not specify this attribute, the default value 1d takes effect.

     To configure an archive path and generate a log piece every two days, execute either of the following statements:

     ALTER SYSTEM SET LOG_ARCHIVE_DEST='LOCATION=file:///data/nfs/backup/archive BINDING=Optional PIECE_SWITCH_INTERVAL=1d' TENANT = mysql_tenant;
     

     ALTER SYSTEM SET LOG_ARCHIVE_DEST='LOCATION=file:///data/nfs/backup/archive BINDING=Optional PIECE_SWITCH_INTERVAL=1d';
     

Considerations

After you configure the LOG_ARCHIVE_DEST parameter, by default, the system creates a file named format in the directory to which the specified destination belongs. This file is used to verify the validity information of the archive destination and ensure the integrity of data in the destination. Therefore, note the following when you configure the log archive destination:

• If the format file does not exist, the directory where the configured destination is located must be empty so that the LOG_ARCHIVE_DEST parameter can be set. If this directory is not empty, the system returns the -9080 error to indicate that the format file does not exist.

• If the format file exists, its content must be verified so that the parameter can be set. Otherwise, the system returns the -9081 error to indicate that the format file does not match. The content of the format file is verified to check whether the types of the cluster, tenant, and backup destination in the file match those of the current cluster, tenant, and backup destination.

• When you execute a backup job, the job fails to be initiated if the format file does not exist or fails the verification.

In addition, incremental configuration is not supported after the archive destination is configured. Assume that the BINDING attribute is set to Mandatory and the PIECE_SWITCH_INTERVAL attribute is set to 1d for the archive path /data/nfs/backup/archive in NFS. To change the value of PIECE_SWITCH_INTERVAL to 2d and keep the setting of the BINDING attribute to Mandatory, you still need to specify the values of other attributes in the statement. If you do not specify a value for an attribute, the default value is used for the attribute.

Execute the following statement to modify the attribute settings:

ALTER SYSTEM SET LOG_ARCHIVE_DEST = 'LOCATION=file:///data/nfs/backup/archive BINDING=Mandatory PIECE_SWITCH_INTERVAL=2d' TENANT = mysql_tenant;

Set the archiving status of the archive destination

By default, the archiving status of a newly configured archive destination is ENABLE. You can query the DBA_OB_ARCHIVE_DEST view for the archiving status of the archive destination. For more information, see View the archiving parameter settings. If ARCHIVELOG has been enabled for this tenant, the system automatically triggers an archiving job to archive logs to the specified path of the destination.

The following table describes the archiving status of the archive destination.

Perform the following steps to set the archiving status of the archive destination to DEFER or ENABLE based on the actual situation.

1. Log on to the database as an administrator of the sys tenant or a user tenant.

   Note

   The administrator user of a MySQL tenant is root and that of an Oracle tenant is SYS.

2. Enable or disable archiving at the archive destination based on the actual situation.

   • Enable archiving at the archive destination.

     • Enable archiving for a user tenant from the sys tenant.

       ALTER SYSTEM SET LOG_ARCHIVE_DEST_STATE='ENABLE' TENANT = tenant_name;
       

     • Enable archiving for a user tenant.

       ALTER SYSTEM SET LOG_ARCHIVE_DEST_STATE='ENABLE';
       

     After archiving is enabled at the archive destination, an archiving job will be triggered after ARCHIVELOG is enabled for the tenant, to archive logs to the specified path of the destination. If ARCHIVELOG has been enabled for the tenant, an archiving job is automatically triggered.

   • Disable archiving at the archive destination.

     • Disable archiving for a user tenant from the sys tenant.

       ALTER SYSTEM SET LOG_ARCHIVE_DEST_STATE='DEFER' TENANT = tenant_name;
       

     • Disable archiving for a user tenant.

       ALTER SYSTEM SET LOG_ARCHIVE_DEST_STATE='DEFER';
       

     After archiving is disabled at the archive destination, the ongoing archiving job will be suspended. You can set the archiving status of the archive destination to ENABLE to resume the archiving job.

References

• View the archiving parameter settings
• View the archiving progress
• View the archiving history