• ADG环境搭建


    一:实验环境介绍
    PC机系统: CentOS 6.5(64位)
    数据库版本: Oracle 11gR2 11.2.0.4 (64位)
    IP地址规划:
    主数据库
    10.110.9.41
    SID:orapri
    db_name:orapri
    db_unique_name:orapri
    备份数据库
    10.110.9.40
    SID:orastd
    db_name:orapri
    db_unique_name:orastd
    二:安装数据库软件前的系统配置 (主库和备库端都要做下列操作),如果是PDT系统安装数据库可以省略此步
    1.装包
    binutils compat-libstdc++-33 elfutils-libelf elfutils-libelf-devel glibc glibc-common glibc-devel gcc gcc-c++ libaio-devel libaio libgcc libstdc++ libstdc++-devel make sysstat unixODBC unixODBC-devel pdksh numactl-devel glibc-headers
    现在是通过yum方式进行安装的。
    2.创建相关的组与用户:
    groupadd dba
    groupadd oinstall
    groupadd oper
    useradd -g oinstall -G dba,oper oracle
    passwd oracle
    3.创建所需的目录并赋予特定的属主和属组
    mkdir -p /opt/local/oracle/app/product/11.2.0/db_1
    chown -R oracle:oinstall/opt/local/oracle
    chmod -R755/opt/local/oracle
    4.修改/etc/sysctl.conf文件,在最下新增
    #setting oracle
    fs.aio-max-nr = 1048576
    fs.file-max = 6815744
    kernel.shmall = 2097152
    kernel.shmmax = 4294967295
    kernel.shmmni = 4096
    kernel.sem = 250 32000 100 128
    net.ipv4.ip_local_port_range=3276861000
    net.core.rmem_default = 262144
    net.core.rmem_max = 4194304
    net.core.wmem_default = 262144
    net.core.wmem_max = 1048576

    --以前系统已经配置参数
    kernel.shmall = 4294967296 oracle官网推荐值2097152,系统现有的值4294967296需修改,推荐值(内存大小KB/4KB)
    kernel.shmmax = 68719476736Minimum: 536870912Maximum: 比物理内存小1个字节的值 建议:超过物理内存的80%

    后需执行sysctl -p命令使其生效.
    5.修改vi /etc/pam.d/login文件,在最下新增(使/etc/security/limits.conf 文件配置生效)
    #setting oracle
    session required pam_limits.so
    6.修改/etc/security/limits.conf文件,在最下新增
    #setting oracle
    oracle soft nproc 65535
    oracle hard nproc 65535
    oracle soft nofile 65535
    oracle hard nofile 65536
    oracle soft stack 10240
    7.修改参数配置文件/etc/profile,新增
    #setting oracle
    export ORACLE_BASE=/opt/local/oracle/app
    export ORACLE_HOME=$ORACLE_BASE/product/11.2.0/db_1
    export PATH=$PATH:$ORACLE_HOME/bin
    export ORACLE_PID=oradb
    export ORACLE_SID=oradb
    export NLS_LANG="AMERICAN_AMERICA.AL32UTF8"
    export ORACLE_HOME_LISTNER=$ORACLE_HOME
    8.在root用户下执行以下命令
    usermod -G oinstall root
    9.使用oracle用户登录服务器,修改~/.bash_profile文件,新增
    #setting oracle
    export ORACLE_BASE=/opt/local/oracle/app
    export ORACLE_HOME=$ORACLE_BASE/product/11.2.0/db_1
    export PATH=$PATH:$ORACLE_HOME/bin
    export ORACLE_PID=oradb
    export ORACLE_SID=oradb
    export LD_LIBRARY_PATH=$ORACLE_HOME/lib:$LD_LIBRARY_PATH
    export NLS_LANG="AMERICAN_AMERICA.AL32UTF8"
    export ORACLE_HOME_LISTNER=$ORACLE_HOME
    10.修改主备机名编辑主备机/etc/hosts文件
    主:
    127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
    ::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
    10.110.9.41 primary

    备:
    127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
    ::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
    10.110.9.40 standy

    三:开始安装oracle11g数据库软件 (主库和备库端都要做下列操作)
    安装过程:详见《VOS系统oracle数据库安装配置使用说明书》
    注意:主库在安装完软件后需要进行DBCA建库操作,推荐不要启用归档模式,会节省时间,备库端不要建库!可以开启监听程序
    四:开始搭建Dataguard
    1:将数据库改为强制日志模式 (此步骤只在主库上做)
    [oracle@primary ~]$ sqlplus / as sysdba

    SQL*Plus: Release 11.2.0.4.0 Production on Mon Dec 31 21:35:05 2018

    Copyright (c) 1982, 2013, Oracle. All rights reserved.


    Connected to:
    Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
    With the Partitioning, OLAP, Data Mining and Real Application Testing options

    SQL> select name,log_mode,force_logging from v$database;

    NAME LOG_MODE FORCE_LOG
    --------------------------- ------------------------------------ ---------
    ORAPRI ARCHIVELOG NO

    SQL>
    SQL> alter database force logging;

    Database altered.

    SQL> select name,log_mode,force_logging from v$database;

    NAME LOG_MODE FORCE_LOG
    --------------------------- ------------------------------------ ---------
    ORAPRI ARCHIVELOG YES
    SQL> exit
    Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
    With the Partitioning, OLAP, Data Mining and Real Application Testing options
    [oracle@primary ~]$
    2:创建密码文件 (此步骤只在主库上做)
    注意:两端分别创建自己的密码文件好像有问题,备库的密码文件需要跟主库一致,否则导致日志传输不到备库,有待验证。我最后是将主库的密码文件直接copy到备库,重命名后使用。
    [oracle@primary ~]$ cd $ORACLE_HOME/dbs
    [oracle@primary dbs]$ ls
    hc_orapri.dat initorapri.ora lkORAPRI orapwpri spfileorapri.ora
    init.ora lkORADB orapworapri snapcf_orapri.f spfileorapri.ora_bak
    [oracle@primary dbs]$
    已经有一个密码文件了
    [oracle@primary dbs]$ orapwd file=orapwpri password=sysdba force=y
    这条命令可以手动生成密码文件,force=y的意思是强制覆盖当前已有的密码文件(如果有可以不建立)

    将主库的密码文件copy给备库,并重命名
    [oracle@primary dbs]$ scp orapwpri 10.110.9.40:$ORACLE_HOME/dbs/orapwstd
    3:创建standby redolog日志组 (此步骤只在主库上做)
    原则:
    1:standby redo log的文件大小与primary 数据库online redo log 文件大小相同
    2:standby redo log日志文件组的个数依照下面的原则进行计算:
    Standby redo log组数公式>=(每个instance日志组个数+1)*instance个数
    假如只有一个节点,这个节点有三组redolog,
    所以Standby redo log组数>=(3+1)*1 == 4
    所以至少需要创建4组Standby redo log
    查看当前线程与日志组的对应关系及日志组的大小:
    SQL> select thread#,group#,bytes/1024/1024 from v$log;

    THREAD# GROUP# BYTES/1024/1024
    ---------- ---------- ---------------
    1 1 50
    1 2 50
    1 3 50

    SQL>
    如上,我现在的环境有三组redolog,每个日志组的大小都是50M,
    所以Standby redo log组数>=(3+1)*1== 4
    所以至少需要创建4组Standby redo log,大小均为50M
    SQL> col member for a50
    SQL> select group#,member from v$logfile;

    GROUP# MEMBER
    ---------- --------------------------------------------------
    3 /opt/local/oracle/app/oradata/orapri/redo03.log
    2 /opt/local/oracle/app/oradata/orapri/redo02.log
    1 /opt/local/oracle/app/oradata/orapri/redo01.log

    3 rows selected.

    SQL>
    先手动创建standby log日志组所需的目录:(创建新目录只是为了便于区分,并非必须)
    [oracle@primary dbs]$ cd /opt/local/oracle/app/oradata/
    [oracle@primary oradata]$ mkdir standbylog
    新建4个日志组作为standby redolog日志组,大小与原来的日志组一致:
    由于已经存在group1-3,,所以group号只能从4开始
    SQL>
    alter database add standby logfile group 4 '/opt/local/oracle/app/oradata/standbylog/std_redo04.log' size 50m;
    alter database add standby logfile group 5 '/opt/local/oracle/app/oradata/standbylog/std_redo05.log' size 50m;
    alter database add standby logfile group 6 '/opt/local/oracle/app/oradata/standbylog/std_redo06.log' size 50m;
    alter database add standby logfile group 7 '/opt/local/oracle/app/oradata/standbylog/std_redo07.log' size 50m;
    SQL>
    查看standby 日志组的信息:
    SQL> set linesize 1000
    SQL> select group#,sequence#,status, bytes/1024/1024 from v$standby_log;

    GROUP# SEQUENCE# STATUS BYTES/1024/1024
    ---------- ---------- ------------------------------ ---------------
    4 0 UNASSIGNED 50
    5 0 UNASSIGNED 50
    6 0 UNASSIGNED 50
    7 0 UNASSIGNED 50

    SQL>
    查看当前有哪些日志组及其成员:
    SQL> set pagesize 100
    SQL> col member for a60
    SQL> select group#,member from v$logfile order by group#;

    GROUP# MEMBER
    ---------- ------------------------------------------------------------
    1 /opt/local/oracle/app/oradata/orapri/redo01.log
    2 /opt/local/oracle/app/oradata/orapri/redo02.log
    3 /opt/local/oracle/app/oradata/orapri/redo03.log
    4 /opt/local/oracle/app/oradata/standbylog/std_redo04.log
    5 /opt/local/oracle/app/oradata/standbylog/std_redo05.log
    6 /opt/local/oracle/app/oradata/standbylog/std_redo06.log
    7 /opt/local/oracle/app/oradata/standbylog/std_redo07.log
    4:修改主库的pfile参数文件 (此步骤只在主库上做)
    创建pfile文件
    SQL> create pfile from spfile;

    File created.

    SQL>
    修改pfile文件
    orapri.__db_cache_size=1040187392
    orapri.__java_pool_size=16777216
    orapri.__large_pool_size=33554432
    orapri.__oracle_base='/opt/local/oracle/app'#ORACLE_BASE set from environment
    orapri.__pga_aggregate_target=838860800
    orapri.__sga_target=1442840576
    orapri.__shared_io_pool_size=0
    orapri.__shared_pool_size=335544320
    orapri.__streams_pool_size=0
    *.audit_file_dest='/opt/local/oracle/app/admin/orapri/adump'
    *.audit_trail='db'
    *.compatible='11.2.0.4.0'
    *.control_files='/opt/local/oracle/app/oradata/orapri/control01.ctl','/opt/local/oracle/app/flash_recovery_area/orapri/control02.ctl'
    *.db_block_size=8192
    *.db_domain=''
    *.db_name='orapri'
    *.db_recovery_file_dest='/opt/local/oracle/app/flash_recovery_area'
    *.db_recovery_file_dest_size=4385144832
    *.diagnostic_dest='/opt/local/oracle/app'
    *.dispatchers='(PROTOCOL=TCP) (SERVICE=orapriXDB)'
    *.open_cursors=300
    *.pga_aggregate_target=825229312
    *.processes=150
    *.remote_login_passwordfile='EXCLUSIVE'
    *.sga_target=1428160512
    *.undo_tablespace='UNDOTBS1'
    #新增部分
    *.db_unique_name='orapri'
    *.log_archive_config='dg_config=(orapri,orastd)'
    *.log_archive_dest_1='location=/opt/local/oracle/app/oracle/arch valid_for=(all_logfiles,all_roles) db_unique_name=orapri'
    *.log_archive_dest_2='service=orastd valid_for=(online_logfiles,primary_role) db_unique_name=orastd'
    *.log_archive_dest_state_1=enable
    *.log_archive_dest_state_2=enable
    *.log_archive_max_processes=4
    *.fal_server='orastd'
    *.fal_client='orapri'
    *.db_file_name_convert='/opt/local/oracle/app/oradata/orastd','/opt/local/oracle/app/oradata/orapri'
    *.log_file_name_convert='/opt/local/oracle/app/oradata/orastd','/opt/local/oracle/app/oradata/orapri'
    *.standby_file_management='auto'

    手动创建归档日志路径
    手工创建/u01/app/oracle/arch:
    [oracle@primary ~]$ mkdir –p /opt/local/oracle/app/oracle/arch/
    5:用修改过的pfile重新创建一个spfile,用于重启数据库 (此步骤只在主库上做)
    关闭数据库:
    SQL> shutdown immediate;
    Database closed.
    Database dismounted.
    ORACLE instance shut down.

    用修改过的pfile重新创建一个spfile:
    SQL> create spfile from pfile;
    此时把数据库改为归档模式: (如果当初建库时选择了启用归档,则此步骤忽略)
    由于当前数据库已关闭,首先需要把数据库启动到mount状态
    SQL> startup mount;
    ORACLE instance started.
    Database mounted.
    SQL> alter database archivelog; 启用归档模式
    Database altered.

    SQL> alter database open; OPEN数据库
    Database altered.

    SQL> archive log list; 查看是否启用归档模式
    SQL> archive log list;
    Database log mode Archive Mode
    Automatic archival Enabled
    Archive destination/opt/local/oracle/app/oracle/arch
    Oldest online log sequence 22
    Next log sequence to archive 24
    Current log sequence 24
    如上,归档路径已经改为/opt/local/oracle/app/oracle/arch,证明对pfile的修改已生效
    6:修改监听文件,添加静态监听 (主库、备库都要做)
    主库:
    [oracle@primary ~]$ cd $ORACLE_HOME/network/admin
    [oracle@primary admin]$ vim listener.ora
    # listener.ora Network Configuration File: /opt/local/oracle/app/product/11.2.0/db_1/network/admin/listener.ora
    # Generated by Oracle configuration tools.

    LISTENER =
    (DESCRIPTION_LIST =
    (DESCRIPTION =
    (ADDRESS = (PROTOCOL = IPC)(KEY = primary))
    (ADDRESS = (PROTOCOL = TCP)(HOST = primary)(PORT = 1521))
    (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
    )
    )

    ADR_BASE_LISTENER = /opt/local/oracle/app

    SID_LIST_LISTENER =
    (SID_LIST =
    (SID_DESC =
    (GLOBAL_DBNAME = orapri)
    (ORACLE_HOME = /opt/local/oracle/app/product/11.2.0/db_1)
    (SID_NAME = orapri)
    )
    )

    [oracle@primary admin]$ vim tnsnames.ora

    # tnsnames.ora Network Configuration File: /opt/local/oracle/app/product/11.2.0/db_1/network/admin/tnsnames.ora
    # Generated by Oracle configuration tools.

    ORAPRI =
    (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = primary)(PORT = 1521))
    (CONNECT_DATA =
    (SERVER = DEDICATED)
    (SERVICE_NAME = orapri)
    )
    )

    pri =
    (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = 10.110.9.41)(PORT = 1521))
    (CONNECT_DATA =
    (SERVER = DEDICATED)
    (SERVICE_NAME = orapri)
    )
    )

    std =
    (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = 10.110.9.40)(PORT = 1521))
    (CONNECT_DATA =
    (SERVER = DEDICATED)
    (SERVICE_NAME = orastd)
    )
    )

    orastd =
    (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = 10.110.9.40)(PORT = 1521))
    (CONNECT_DATA =
    (SERVER = DEDICATED)
    (SERVICE_NAME = orastd)
    )
    )

    备库:
    [oracle@standy ~]$ cd $ORACLE_HOME/network/admin
    [oracle@standy admin]$ vim listener.ora

    # listener.ora Network Configuration File: /opt/local/oracle/app/product/11.2.0/db_1/network/admin/listener.ora
    # Generated by Oracle configuration tools.

    LISTENER =
    (DESCRIPTION_LIST =
    (DESCRIPTION =
    (ADDRESS = (PROTOCOL = IPC)(KEY = standy))
    (ADDRESS = (PROTOCOL = TCP)(HOST = standy)(PORT = 1521))
    (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
    )
    )

    ADR_BASE_LISTENER = /opt/local/oracle/app

    SID_LIST_LISTENER =
    (SID_LIST =
    (SID_DESC =
    (GLOBAL_DBNAME = orastd)
    (ORACLE_HOME = /opt/local/oracle/app/product/11.2.0/db_1)
    (SID_NAME = orastd)
    )
    )

    [oracle@standy admin]$ vim tnsnames.ora

    # tnsnames.ora Network Configuration File: /opt/local/oracle/app/product/11.2.0/db_1/network/admin/tnsnames.ora
    # Generated by Oracle configuration tools.

    ORAPRI =
    (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = primary)(PORT = 1521))
    (CONNECT_DATA =
    (SERVER = DEDICATED)
    (SERVICE_NAME = orapri)
    )
    )

    pri =
    (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = 10.110.9.41)(PORT = 1521))
    (CONNECT_DATA =
    (SERVER = DEDICATED)
    (SERVICE_NAME = orapri)
    )
    )

    std =
    (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = 10.110.9.40)(PORT = 1521))
    (CONNECT_DATA =
    (SERVER = DEDICATED)
    (SERVICE_NAME = orastd)
    )
    )

    orastd =
    (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = 10.110.9.40)(PORT = 1521))
    (CONNECT_DATA =
    (SERVER = DEDICATED)
    (SERVICE_NAME = orastd)
    )
    )
    使新增加的监听生效: (主库和备库端都要做)
    [oracle@standy admin]$ lsnrctl stop
    [oracle@standy admin]$ lsnrctl start

    确认新增加的静态监听有效:
    主库:
    [oracle@standy admin]$ lsnrctl status

    备库:
    [oracle@standy admin]$ lsnrctl status

    7:在备库端,修改pfile参数文件 (只在备库端做)
    orapri.__db_cache_size=1040187392
    orapri.__java_pool_size=16777216
    orapri.__large_pool_size=33554432
    orapri.__oracle_base='/opt/local/oracle/app'#ORACLE_BASE set from environment
    orapri.__pga_aggregate_target=838860800
    orapri.__sga_target=1442840576
    orapri.__shared_io_pool_size=0
    orapri.__shared_pool_size=335544320
    orapri.__streams_pool_size=0
    *.audit_file_dest='/opt/local/oracle/app/admin/orastd/adump'
    *.audit_trail='db'
    *.compatible='11.2.0.4.0'
    *.control_files='/opt/local/oracle/app/oradata/orastd/control01.ctl','/opt/local/oracle/app/flash_recovery_area/orastd/control02.ctl'
    *.db_block_size=8192
    *.db_domain=''
    *.db_name='orapri'
    *.db_recovery_file_dest='/opt/local/oracle/app/flash_recovery_area'
    *.db_recovery_file_dest_size=4385144832
    *.diagnostic_dest='/opt/local/oracle/app'
    *.dispatchers='(PROTOCOL=TCP) (SERVICE=orapriXDB)'
    *.open_cursors=300
    *.pga_aggregate_target=825229312
    *.processes=150
    *.remote_login_passwordfile='EXCLUSIVE'
    *.sga_target=1428160512
    *.undo_tablespace='UNDOTBS1'

    #新增内容
    *.db_unique_name='orastd'
    *.log_archive_config='dg_config=(orapri,orastd)'
    *.log_archive_dest_1='location=/opt/local/oracle/app/oracle/arch valid_for=(all_logfiles,all_roles) db_unique_name=orastd'
    *.log_archive_dest_2='service=orapri valid_for=(online_logfiles,primary_role) db_unique_name=orapri'
    *.log_archive_dest_state_1=enable
    *.log_archive_dest_state_2=enable
    *.log_archive_max_processes=4
    *.fal_server='orastd'
    *.fal_client='orapri'
    *.db_file_name_convert='/opt/local/oracle/app/oradata/orapri','/opt/local/oracle/app/oradata/orastd'
    *.log_file_name_convert='/opt/local/oracle/app/oradata/orapri','/opt/local/oracle/app/oradata/orastd'
    *.standby_file_management='auto'

    8:在备库端手工创建所需的目录 (备库端做,不提前创建的话恢复时会报错!)
    mkdir -pv /opt/local/oracle/app/admin/orastd/adump
    mkdir -pv /opt/local/oracle/app/diag/rdbms/orastd/orastd/trace
    mkdir -pv /opt/local/oracle/app/oracle/arch
    mkdir -pv /opt/local/oracle/app/oradata/orastd
    mkdir -pv /opt/local/oracle/app/oradata/standbylog
    mkdir -pv /opt/local/oracle/app/flash_recovery_area

    9:用修改后的pfile创建一个spfile,用于启动数据库 (备库端做)
    [oracle@standy ~]$ sqlplus / as sysdba
    Connected to an idle instance.

    SQL> create spfile from pfile;
    File created.

    将数据库启动到nomount状态:
    SQL> startup nomount;
    ORACLE instance started.

    Total System Global Area 839282688 bytes
    Fixed Size 2233000 bytes
    Variable Size 482348376 bytes
    Database Buffers 352321536 bytes
    Redo Buffers 2379776 bytes
    SQL>
    10:利用RMAN在备库上恢复主库 (备库端做)
    [oracle@standy ~]$ rman target sys/sysdba@pri auxiliary sys/sysdba@std nocatalog

    Recovery Manager: Release 11.2.0.4.0 - Production on Mon Dec 31 22:00:57 2018

    Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved.

    connected to target database: ORAPRI (DBID=2916030696)
    using target database control file instead of recovery catalog
    connected to auxiliary database: ORAPRI (DBID=2916030696)

    RMAN> duplicate target database for standby from active database nofilenamecheck; --备机同步主机数据
    ...
    Finished Duplicate Db at 16-MAR-16

    RMAN>
    恢复数据库结束

    12:分别查看主库和备库的归档序列号是否一致:
    主机:
    SQL> archive log list;
    Database log mode Archive Mode
    Automatic archival Enabled
    Archive destination /opt/local/oracle/app/oracle/arch
    Oldest online log sequence 26
    Next log sequence to archive 28
    Current log sequence 28
    SQL>
    备机:
    SQL> archive log list;
    Database log mode Archive Mode
    Automatic archival Enabled
    Archive destination /opt/local/oracle/app/oracle/arch
    Oldest online log sequence 26
    Next log sequence to archive 0
    Current log sequence 28
    SQL>

    13 : 启动备机为只读模式
    启用备机实时查询
    SQL> startup mount
    SQL>alter database recover managed standby database using current logfile disconnect;
    SQL> alter database recover managed standby database cancel;
    SQL> alter database open;
    SQL> alter database recover managed standby database using current logfile disconnect;

    14 : 修改数据库保护模式
    adg的数据传输应用三大模式转换
    1.最大可用性模式(Maximum Availability)
    1)该模式提供了仅次于“最大保护模式”的数据保护能力;
    2)要求至少一个物理备库收到重做日志后,主库的事务才能够提交;
    3)主库找不到合适的备库写入时,主库不会关闭,而是临时降低到“最大性能模式”模式,直到问题得到处理;
    4)优点:该模式可以在没有问题出现的情况下,保证备库没有数据丢失,是一种折中的方法;
    5)缺点:在正常运行的过程中缺点是主库的性能受到诸多因素的影响。
    2.最大性能模式(Maximum Performance)
    1)该模式是默认模式,可以保证主数据库的最高可用性;
    2)保证主库运行过程中不受备库的影响,主库事务正常提交,不因备库的任何问题影响到主库的运行;
    4)优点:避免了备库对主数据库的性能和可用性影响;
    5)缺点:如果与主库提交的事务相关的恢复数据没有发送到备库,这些事务数据将被丢失,不能保证数据无损失。
    3.最大保护模式(Maximum Protection)
    1)这种模式提供了最高级别的数据保护能力;
    2)要求至少一个物理备库收到重做日志后,主库的事务才能够提交;
    3)主库找不到合适的备库写入时,主库会自动关闭,防止未受保护的数据出现;
    4)优点:该模式可以保证备库没有数据丢失;
    5)缺点:主库的自动关闭会影响到主库的可用性,同时需要备库恢复后才能提交,对网络等客观条件要求非常的高,主库的性能会因此受到非常大的冲击。

    #primary 端查看,我们可以看到数据库的保护模式为最大性能
    SQL> select database_role,protection_mode,protection_level,open_mode from v$database;
    #standby 端查看,也是一样的。
    SQL> select database_role,protection_mode,protection_level,open_mode from v$database;

    主备机mount状态下切换保护模式:
    alter database set standby database to maximize performance; --切换为最大性能
    alter database set standby database to maximize availability; --切换为最大可用
    alter database set standby database to maximize protection; --切换为最大保护

    15 : ADG常用运维命令和脚本

    主要做主从数据库同步,通过Dataguard实现,当运行一段时间后,发现主从数据库的数据不一致了,从库无法启动,报“ORA-01196: 文件 1 由于介质恢复会话失败而不一致”这个错误,具体日志信息如下:
    SQL> alter database open;
    alter database open
    *
    第 1 行出现错误:
    ORA-10458: standby database requires recovery
    ORA-01196: 文件 1 由于介质恢复会话失败而不一致
    ORA-01110: 数据文件 1: 'D:APPADMINISTRATORORADATAORCLSYSTEM01.DBF'

    解决方法:
    从库启动到mount状态:
    SQL>SHUTDOWN IMMEDIATE
    SQL>STARTUP MOUNT;
    SQL>alter database recover managed standby database using current logfile disconnect;
    到主库上操作:
    SQL>ALTER SYSTEM SWITCH LOGFILE;
    多操作几次,操作之后,稍等一段时间,时间视网速而定,过一段时间后,在主库上查询一下规定情况:
    SQL>SELECT NAME,SEQUENCE#,ARCHIVED,APPLIED FROM V$ARCHIVED_LOG ORDER BY SEQUENCE#;
    如果返回结果"APPLIED"都是“YES”或者只有最后一个是“NO”的话,说明全部归档日志全部已经归档完了,此时到备库上上操作:
    备库操作:
    SQL>alter database recover managed standby database cancel;
    SQL>alter database open;
    SQL>alter database recover managed standby database using current logfile disconnect;

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  • 原文地址:https://www.cnblogs.com/dbalightyear/p/11228342.html
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