Oracle Rman多通道故障转移问题分析

IT小Chen 2021-05-10

1834

问题现象：

近期公司做数据库冗余测试，停掉RAC其中一个节点后，发现本地自动备份和清理归档的脚本执行失败。

脚本类似如下：

run {
allocate channel ch1 type disk connect sys/oracle@rac1:1521/oradb;
allocate channel ch2 type disk connect sys/oracle@rac2:1521/oradb;
******
}

报错如下：
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-12001: could not open channel ch1
RMAN-10008: could not create channel context
RMAN-10003: unable to connect to target database
ORA-12514: TNS:listener does not currently know of service requested in connect descriptor

原因分析：

经测试，此写法无法实现多通道故障转移。

测试过程如下：
[oracle@rac2 cjc]$ rman target /
RMAN> run {
allocate channel ch1 type disk connect sys/oracle@rac1:1521/oradb;
allocate channel ch2 type disk connect sys/oracle@rac2:1521/oradb;
show all;
}2> 3> 4> 5> 

allocated channel: ch1
channel ch1: SID=716 instance=oradb1 device type=DISK

allocated channel: ch2
channel ch2: SID=730 instance=oradb2 device type=DISK

RMAN configuration parameters for database with db_unique_name ORADB are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default
CONFIGURE BACKUP OPTIMIZATION OFF; # default
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE CONTROLFILE AUTOBACKUP ON; # default
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE MAXSETSIZE TO UNLIMITED; # default
CONFIGURE ENCRYPTION FOR DATABASE OFF; # default
CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default
CONFIGURE COMPRESSION ALGORITHM 'BASIC' AS OF RELEASE 'DEFAULT' OPTIMIZE FOR LOAD TRUE ; # default
CONFIGURE RMAN OUTPUT TO KEEP FOR 7 DAYS; # default
CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/oracle/db/product/19.0.0/dbs/snapcf_oradb1.f'; # default
released channel: ch1
released channel: ch2

停掉节点1实例后：

[oracle@rac1 ~]$ sqlplus  as sysdba
SQL*Plus: Release 19.0.0.0.0 - Production on Sun May 9 18:51:48 2021
Version 19.3.0.0.0
Copyright (c) 1982, 2019, Oracle.  All rights reserved.

Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.3.0.0.0
SQL> shutdown immediate

再次连接rman，报错

oracle@rac2 ~]$ rman target /
Recovery Manager: Release 19.0.0.0.0 - Production on Sun May 9 18:56:39 2021
Version 19.3.0.0.0
Copyright (c) 1982, 2019, Oracle and/or its affiliates.  All rights reserved.
connected to target database: ORADB (DBID=2810081861)

RMAN> run {
allocate channel ch1 type disk connect sys/oracle@rac1:1521/oradb;
allocate channel ch2 type disk connect sys/oracle@rac2:1521/oradb;
show all;
}2> 3> 4> 5> 

using target database control file instead of recovery catalog
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-12001: could not open channel ch1
RMAN-10008: could not create channel context
RMAN-10003: unable to connect to target database
ORA-12514: TNS:listener does not currently know of service requested in connect descriptor

是否和通道顺序有关呢？将ch2写到前面，测试报错依旧，看来和顺序无关

RMAN> run {
allocate channel ch2 type disk connect sys/oracle@rac2:1521/oradb;
allocate channel ch1 type disk connect sys/oracle@rac1:1521/oradb;
show all;
}2> 3> 4> 5> 

allocated channel: ch2
channel ch2: SID=25 instance=oradb2 device type=DISK

released channel: ch2
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-12001: could not open channel ch1
RMAN-10008: could not create channel context
RMAN-10003: unable to connect to target database
ORA-12514: TNS:listener does not currently know of service requested in connect descriptor

把停掉的节点通道注释掉以后可以正常执行命令

run {
#allocate channel ch1 type disk connect sys/oracle@rac1:1521/oradb;
allocate channel ch2 type disk connect sys/oracle@rac2:1521/oradb;
show all;
}

[oracle@rac2 ~]$ rman target /
Recovery Manager: Release 19.0.0.0.0 - Production on Sun May 9 18:59:03 2021
Version 19.3.0.0.0
Copyright (c) 1982, 2019, Oracle and/or its affiliates.  All rights reserved.
connected to target database: ORADB (DBID=2810081861)

RMAN> run {
#allocate channel ch1 type disk connect sys/oracle@rac1:1521/oradb;
allocate channel ch2 type disk connect sys/oracle@rac2:1521/oradb;
show all;
}2> 3> 4> 5> 

using target database control file instead of recovery catalog
allocated channel: ch2
channel ch2: SID=479 instance=oradb2 device type=DISK

RMAN configuration parameters for database with db_unique_name ORADB are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default
CONFIGURE BACKUP OPTIMIZATION OFF; # default
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE CONTROLFILE AUTOBACKUP ON; # default
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE MAXSETSIZE TO UNLIMITED; # default
CONFIGURE ENCRYPTION FOR DATABASE OFF; # default
CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default
CONFIGURE COMPRESSION ALGORITHM 'BASIC' AS OF RELEASE 'DEFAULT' OPTIMIZE FOR LOAD TRUE ; # default
CONFIGURE RMAN OUTPUT TO KEEP FOR 7 DAYS; # default
CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/oracle/db/product/19.0.0/dbs/snapcf_oradb2.f'; # default
released channel: ch2

如何在RAC两个节点都保持正常的情况下，可以使用多个节点通道并发提高速度，在某个节点出现故障，通道自动转移到另一个节点呢？

可以尝试使用10g连接RAC的指定多个vip的方式。

将如下内容加入到tnsnames.ora文件中。

vip1 =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = rac1)(PORT = 1521))
    (ADDRESS = (PROTOCOL = TCP)(HOST = rac2)(PORT = 1521))
#(LOAD_BALANCE = yes) 
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = oradb)
    )
  )
  
vip2 =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = rac2)(PORT = 1521))
    (ADDRESS = (PROTOCOL = TCP)(HOST = rac1)(PORT = 1521))
    #(LOAD_BALANCE = yes) 
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = oradb)
    )
  )

测试在不使用LOAD_BALANCE = yes情况下，优先连接第一个地址，当第一个地址连不通了，会自动去连接第二个地址，实现故障转移。

[oracle@rac2 admin]$ sqlplus system/oracle@vip1
show parameter name
[oracle@rac2 admin]$ sqlplus system/oracle@vip2
show parameter name

修改RMAN脚本

run {
allocate channel ch1 type disk connect sys/oracle@vip1;
allocate channel ch2 type disk connect sys/oracle@vip2;
show all;
release channel ch1;
release channel ch2;
}

在节点1实例不启动的情况下，可以正常执行命令了。

[oracle@rac2 admin]$ rman target /
Recovery Manager: Release 19.0.0.0.0 - Production on Sun May 9 19:36:14 2021
Version 19.3.0.0.0
Copyright (c) 1982, 2019, Oracle and/or its affiliates.  All rights reserved.
connected to target database: ORADB (DBID=2810081861)

RMAN> run {
allocate channel ch1 type disk connect sys/oracle@vip1;
allocate channel ch2 type disk connect sys/oracle@vip2;
show all;
release channel ch1;
release channel ch2;
}2> 3> 4> 5> 6> 7> 

using target database control file instead of recovery catalog
allocated channel: ch1
channel ch1: SID=717 instance=oradb1 device type=DISK

allocated channel: ch2
channel ch2: SID=489 instance=oradb2 device type=DISK


RMAN configuration parameters for database with db_unique_name ORADB are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default
CONFIGURE BACKUP OPTIMIZATION OFF; # default
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE CONTROLFILE AUTOBACKUP ON; # default
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE MAXSETSIZE TO UNLIMITED; # default
CONFIGURE ENCRYPTION FOR DATABASE OFF; # default
CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default
CONFIGURE COMPRESSION ALGORITHM 'BASIC' AS OF RELEASE 'DEFAULT' OPTIMIZE FOR LOAD TRUE ; # default
CONFIGURE RMAN OUTPUT TO KEEP FOR 7 DAYS; # default
CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/oracle/db/product/19.0.0/dbs/snapcf_oradb2.f'; # default
released channel: ch1
released channel: ch2

###chenjuchao 20210509 20:30###

oracle

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Oracle Rman多通道故障转移问题分析

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