Slave database Introduction

Backup Database Type: 1. Physical backup database; 2. Logical backup database; 3. snapshot backup database.

You can configure one or more types of slave databases at the same time.

1. Physical standby Database

It is a block-to-block copy of the master database. The application retries the log and receives the redo data application from the master database to the physical standby database.

It can be enabled in read only mode. After 11 GB, you can configure active DG to enable the application to redo data in read-only mode.

 

Advantages of the physical standby database:

1. Disaster Recovery and high availability

2. Data protection

Supports multiple DDL and DML operations

3. reduce the load on the master database

Open in read-only mode for reports and queries

4. Performance

Bottom-layer copy, bypassing the SQL-level code Layer

 

2. Logical standby Database

When the SQL application updates the slave database, the database structure changes. When the SQL application is applied, the slave database is open and can be directly queried and reported.

Working mechanism: DG converts the redo log data to SQL statements and then executes SQL statements on the slave database. Although the slave database is opened in read/write mode, however, the data generated by the SQL application can only be used for read/write operations.

The logical standby database has some restrictions on the data type, table type, and DDL/DML operation type.

 

Benefits of logical standby Databases

1. prevent additional Fault Types

2. Make full use of resources

3. Load Balancing

4. Requirements for making full use of reports and decision support

5. Minimize software upgrade time

 

3. snapshot slave Database

The physical standby database can be changed to the snapshot standby database and then opened in read/write mode. The snapshot standby database accepts redo and archivelog, but does not apply them. Apply redo and archivelog only after the physical standby database is installed.

 

Advantages of the snapshot slave database:

1. provides accurate data replication from the production database to the development or test database

2. You can easily update and synchronize existing production data by converting to a physical standby database.

3. You can enable it in read/write mode to modify data.

 

Configure, implement, and manage slave databases:

1. Em

2. sqlplus

3. pfile

4. dgmgrl

 

Prerequisites for DG Configuration

11G: the master and slave databases can run on different CPUs, operating systems, operating systems with different digits, and Oracle software with different digits. The database versions must be consistent.

Hardware and operating system requirements:

Physical standby database (MOS: 413484.1 ):

Platform_id	Platform_name Release name	Platform_ids supported within the same data guard configuration when using data guard redo apply (physical standby)
2	Solaris [Tm] OE (64-bit) Solaris operating system (iSCSI) (64-bit)	2 6-this is not supported due to issues reported in bug 12702521
3	HP-UX (64-bits) HP-UX PA-RISC	3 4-Oracle 10g onward, see support Note: 395982.1 andnote: 414043.1
4	HP-UX Ia (64-bit) HP-UX, itanium	4 3-Oracle 10g onward, see support Notes: 395982.1 andnote: 414043.1
5	HP Tru64 UNIX HP Tru64 UNIX	5
6	Ibm aix on Power Systems (64-bit)	2-this is not supported due to issues reported in bug 12702521 6
7	Microsoft Windows (32-bit) Microsoft Windows (x86)	7 8, 12-Oracle 10g onward, see support Note: 414043.1 10-Oracle 11g onward, requires patch 13104881 11, 13-Oracle 11g onward, see support Note: 414043.1, also requires patch 13104881
8	Microsoft Windows Ia (64-bit) Microsoft Windows (64-bit itanium)	7-Oracle 10g onward, see support Note: 414043.1 8 12-Oracle 10g onward 11, 13-Oracle 11g onward, requires patch 13104881
9	IBM zseries based Linux Z/Linux	9 18 (64-bit zseries only)
10	Linux (32-bit) Linux x86	7-Oracle 11g onward, requires patch 13104881 10 11, 13-Oracle 10g onward, see support Note: 414043.1
11	Linux Ia (64-bit) Linux itanium	10-Oracle 10g onward, see support Note: 414043.1 11 13-Oracle 10g onward 7-Oracle 11g onward, see support Note: 414043.1, also requirespatch 13104881 8, 12-Oracle 11g onward, requires patch 13104881
12	Microsoft Windows 64-bit for AMD Windows (x86-64)	7-Oracle 10g onward, see support Note: 414043.1 8-Oracle 10g onward 12 11, 13-Oracle 11g onward, requires patch 13104881
13	Linux 64-bit for AMD Linux x86-64	7-Oracle 11g onward, see support Note: 414043.1, also requirespatch 13104881 10-Oracle 10g onward, see support Notes: 414043.1 11-Oracle 10g onward 8, 12-Oracle 11g onward, requires patch 13104881 13 20-Oracle 11g onward
15	HP Open VMS HP OpenVMS alpha HP Ia OpenVMS OpenVMS itanium	15
16	Apple Mac OS Mac OS X Server	16
17	Solaris operating system (x86) Solaris operating system (x86)	17 20-Oracle 10g onward, see support Note: 414043.1
18	IBM power based Linux Linux on power	9 (64-bit zseries only) 18
20	Solaris operating system (amd64) Solaris operating system (x86-64)	13-Oracle 11g onward 17-Oracle 10g onward, see support Note: 414043.1 20

 

Logical standby database (MOS: 1085687.1)

Platform_id	Platform_name Release name	Platform_ids supported within the same data guard configuration when using data guard SQL apply (logical standby)
2	Solaris [Tm] OE (64-bit) Solaris operating system (iSCSI) (64-bit)	2
3	HP-UX (64-bits) HP-UX PA-RISC	3, 4
4	HP-UX Ia (64-bit) HP-UX, itanium	3, 4
5	HP Tru64 UNIX HP Tru64 UNIX	5
6	Aix-based systems (64-bit) Aix5l	6
7	Microsoft Windows (32-bit) Microsoft Windows (x86)	7 10 requires patch for Bug 13104881 8, 12-replication can only occur from a 32-bit primary to a 64-bit standby, once a role transition has promoted the 64-bit system to the primary role, the original 32-bit primary is not supported as a standby database.
8	Microsoft Windows Ia (64-bit) Microsoft Windows (64-bit itanium)	7-replication can only occur from a 32-bit primary to a 64-bit standby, once a role transition has promoted the 64-bit system to the primary role, the original 32-bit primary is not supported as a standby database. 8, 12 11, 13, both require patch for Bug 13104881
9	IBM zseries based Linux Z/Linux	9
10	Linux (32-bit) Linux x86	7. Requires patch for Bug 13104881 10 11, 13-replication can only occur from a 32-bit primary to a 64-bit standby, once a role transition has promoted the 64-bit system to the primary role, the original 32-bit primary is not supported as a standby database.
11	Linux Ia (64-bit) Linux itanium	10-replication can only occur from a 32-bit primary to a 64-bit standby, once a role transition has promoted the 64-bit system to the primary role, the original 32-bit primary is not supported as a standby database. 8. Requires patch for Bug 13104881. 11, 13
12	Microsoft Windows 64-bit for AMD Windows (x86-64)	7-from Oracle 11g onward. replication can only occur from a 32-bit primary to a 64-bit standby, once a role transition has promoted the 64-bit system to the primary role, the original 32-bit primary is not supported as a standby database. 8, 12
13	Linux 64-bit for AMD Linux x86-64	10-replication can only occur from a 32-bit primary to a 64-bit standby, once a role transition has promoted the 64-bit system to the primary role, the original 32-bit primary is not supported as a standby database. 8. Requires patch for Bug 13104881. 11, 13
15	HP Open VMS HP OpenVMS alpha HP Ia OpenVMS OpenVMS itanium	15
16	Apple Mac OS Mac OS X Server	16
17	Solaris operating system (x86) Solaris operating system (x86)	17
18	IBM power based Linux Linux on power	18
20	Solaris operating system (amd64) Solaris operating system (x86-64)	20

Oracle software requirements:

1. DG can only be configured on Oracle Enterprise Edition

2. The Oracle software versions of the master and slave databases must be consistent.

3. The logical standby database can implement the rolling upgrade of RDBMS Software (after 10.1.0.3 ). During the rolling upgrade process, the master and slave databases can run different versions of database software.

4. The compatibility parameter (compatible) of the logical standby database can be higher than that of the primary database. The compatibility of the physical standby database must be the same as that of the primary database.

5. The master database must run in archive mode.

6. The master database can be a single instance or RAC, the slave database can also be a single instance or RAC, And the slave database can be a physical slave database, a logical slave database, and a hybrid type of the snapshot slave Database

7. Each master database and slave database must have their own control files.

8. If the master and slave databases are on the same host, the archive path must be different. Otherwise, the archive of the slave database will overwrite the archive of the master database.

9. Prevent nologging write operations on the master database. Force logging must be enabled on the master database)

10. Users managing master-slave database instances must have sysdba Permissions

11. If one instance uses ASM or OMF, the remaining instances must use ASM or OMF unless a hybrid backup database is configured for migration and maintenance.

 

Directory architecture of the standby Database

The directory architecture of the standby database, data files, log files, archived log files, and the backup database log files should be consistent with the master database as much as possible, which can reduce the maintenance complexity.

Note: When the master and slave databases are on the same host, the directory architecture of the master and slave databases must be different. Otherwise, the slave database will overwrite the files of the master database.

 

Configuration illustration of the Master/Slave database directory

　　　　

Backup location and directory architecture configuration options

Slave Database System	Directory Architecture	Result
Same host	The directory architecture must be different from that of the master database.	1. Manually rename the file name or configure initialization parameters for the standby Database: db_file_name_convert, log_file_name_convert 2. disasters caused by operating system faults cannot be guaranteed, but planned switchover and maintenance work can be provided.
Different Hosts	The directory structure of the master and slave databases is the same.	1. You do not need to rename the file, but you can also set it manually. 2. The master and slave databases are located on different hosts and storage media, which can prevent operating system-level disasters.
Different Hosts	The directory structure of the master and slave databases is different.	1. Manually rename the file name or configure initialization parameters for the standby Database: db_file_name_convert, log_file_name_convert 2. The master and slave databases are located on different hosts and storage media, which can prevent operating system-level disasters.

Slave database Introduction