RMAN redirect restore

Redirecting a restore to a different client

With Netbackup for Oracle you have the option to restore a database to a client other than the one that originally performed the backup. The process of restoring data to another client is called a redirected restore.

The user on client A cannot initiate a redirected restore to client B. Only the user on client B, which is the client receiving the backup image, can initiate the redirected restore.

The following sections describe how to perform a redirected restore using Oracle RMAN.

Server configuration


Ensure that the NetBackup server is configured to allow a redirected restore. The administrator can remove restrictions for all clients by creating the

following file on the Netbackup master server:
/usr/openv/netbackup/db/altnames/No.Restrictions


Or, to restrict clients to restore only from certain other clients, create the following file:


/usr/openv/netbackup/db/altnames/client_name



Where client_name is the name of the client allowed to do the redirected restore (the destination client). Then, add the name of the NetBackup for different server of source client to that file.

Using RMAN to perform a redirected restore

Perform the following procedure on the destination client host if you want to restore any RMAN backups that another client owns.



To perform a redirected restore


1. Enable a network connection to the RMAN catalog database that the source client used.

Note: If the RMAN catalog database has been lost, restore the catalog database first before continuing with the redirected restore.
2. Set the NB_ORA_CLIENT environment variable to the source client.
3. Check the bp.conf files on the source client. Make sure that the CLIENT_NAME variable either is not set or is set to the hostname of the source client.
4. Make the init.ora file of the source client available to the destination client. Copy the file to the destination client or modify the file on the destination

client. Change all location-specific parameters.
5. Grant write permission to the directory to which you want to restore the data files.
6 Set up a password file for the destination client database.
7 Start up the database in the nomount state.
8 Start RMAN, connecting to the catalog.
9 Set dbid to be the DBID of the source client database.
10 Connect to the target database without using a userid and password.
11 Run an RMAN restore script or type the RMAN commands for the restore.

Example
For example, assume the following:

■ Source client is Linux-MDDATA-mddsuwldb01
■ Destination client is Linux-MDDATA-mddsuwldb02
■ Master server is nbms001
■ Rman Catalog database is mddrcat
■ ORACLE_SID is mddrest
■ UNIX user is oracle on both mddsuwldb01 and mddsuwldb02





Using NetBackup for Oracle Performing a restore
1> Create the following file on server nbms001 and edit it to contain the name Linux-MDDATA-mddsuwldb01:

% touch /usr/openv/netbackup/db/altnames/Linux-MDDATA-mddsuwldb02
Or
%touch /usr/openv/netbackup/db/altnames/No.Restrictions

2> Log in to mddsuwldb02 as oracle
3> Set SERVER= nbms001 in /usr/openv/netbackup/bp.conf
This server must be the first server that is listed in the bp.conf file.
4> Modify the network tnsnames.ora file to enable RMAN catalog connection.
5> Set the environment variables ORACLE_SID to test and NB_ORA_CLIENT to camel.
6> Make sure the destination database directory exists and has appropriate access permissions. The data files are restored to the directory path with the same name they had when they were backed up.
7> Create an initmddrest.ora file.
8> Start up the database in a nomount state.

SQL>startup nomount pfile=$ORACLE_HOME/dbs/initmddrest.ora

% rman rcvcat rman/rman@mddrcat
RMAN> set dbid=
RMAN> connect target/
RMAN> run {
RMAN> ALLOCATE CHANNEL CH00 TYPE 'SBT_TAPE';
RMAN> SEND 'NB_ORA_SERV=nbms001, NB_ORA_CLIENT=Linux-MDDATA-mddsuwldb01';
RMAN> restore controlfile;
RMAN> }
SVRMGR> alter database mount;
%orapwd file=$ORACLE_HOME/dbs/orapwmddrest password=
%rman rcvcat rman/rman@mddrcat
RMAN>set dbid=
RMAN>connect target/
RMAN>run {
RMAN> ALLOCATE CHANNEL CH00 TYPE 'SBT_TAPE';
RMAN> ALLOCATE CHANNEL CH01 TYPE 'SBT_TAPE';
RMAN> SEND 'NB_ORA_SERV= nbms001, NB_ORA_CLIENT= Linux-MDDATA-mddsuwldb01';
RMAN> restore database;
RMAN> restore archivelog all;
RMAN> }
SQL>recover database until cancel using backup controlfile;

Now apply the archived logs. Type cancel when you decide to stop
recovery.
SQL>alter database open resetlogs;

Reference : Netbackup for Oracle Administrator’s Guide for Unix and Linux

Part 3 : DBMS_REPAIR scnario

DBMS_REPAIR package is used to work with corruption in the transaction layer and the data layer only (software corrupt blocks).locks with physical corruption (ex. fractured block) are marked as the block is read into the buffer cache and DBMS_REPAIR ignores all blocks marked corrupt.
Step 1: A corrupt block exists in table T1.

 SQL> desc scott.t1

Name Null? Type
---- -------- ----------------------------
COL1 NOT NULL NUMBER(38)
COL2 CHAR(512)


SQL> analyze table t1 validate structure;
analyze table t1 validate structure
*
ERROR at line 1:
ORA-01498: block check failure - see trace file


Step 2 : Dumpfile Details

dump file /u01/app/oracle/admin/mddtest/udump/mddtest_ora_2835.trc

kdbchk: row locked by non-existent transaction
table=0 slot=0
lockid=32 ktbbhitc=1
Block header dump: 0x01800003
Object id on Block? Y
seg/obj: 0xb6d csc: 0x00.1cf5f itc: 1 flg: - typ: 1 - DATA
fsl: 0 fnx: 0x0 ver: 0x01
Itl Xid Uba Flag Lck Scn/Fsc
0x01 xid: 0x0002.011.00000121 uba: 0x008018fb.0345.0d --U- 3 fsc
0x0000.0001cf60



data_block_dump
=============
tsiz: 0x7b8
hsiz: 0x18
pbl: 0x28088044
bdba: 0x01800003
flag=-----------
ntab=1
nrow=3
frre=-1
fsbo=0x18
fseo=0x19d
avsp=0x185
tosp=0x185


0xe:pti[0] nrow=3 offs=0
0x12:pri[0] offs=0x5ff
0x14:pri[1] offs=0x3a6
0x16:pri[2] offs=0x19d
block_row_dump:
[... remainder of file not included]
end_of_block_dump






Step 3: Create repair table and orphan table

SQL>
Declare
begin
dbms_repair.admin_tables (
table_name => 'REPAIR_TABLE',
table_type => dbms_repair.repair_table,
action => dbms_repair.create_action,
tablespace => 'USERS');
end;
/


SQL> select owner, object_name, object_type from dba_objects where object_name like '%REPAIR_TABLE';


OWNER OBJECT_NAME OBJECT_TYPE
-----------------------------
SYS DBA_REPAIR_TABLE VIEW
SYS REPAIR_TABLE TABLE


SQL> declare
begin
dbms_repair.admin_tables (
table_type => dbms_repair.orphan_table,
action => dbms_repair.create_action,
tablespace => 'USERS'); -- default TS of SYS if not specified
end;
/

PL/SQL procedure successfully completed.

SQL> select owner, object_name, object_type from dba_objects where object_name like '%ORPHAN_KEY_TABLE';




OWNER OBJECT_NAME OBJECT_TYPE
------------------------------
SYS DBA_ORPHAN_KEY_TABLE VIEW
SYS ORPHAN_KEY_TABLE TABLE


Step 4: Start check object

set serveroutput on
SQL> declare
rpr_count int;
begin
rpr_count := 0;
dbms_repair.check_object (
schema_name => 'SCOTT',
object_name => 'T1',
repair_table_name => 'REPAIR_TABLE',
corrupt_count => rpr_count);
dbms_output.put_line('repair count: 'to_char(rpr_count));
end;
/
repair count: 1

PL/SQL procedure successfully completed.


SQL> select object_name, block_id, corrupt_type, marked_corrupt,corrupt_description, repair_description from repair_table;


OBJECT_NAME : T1
BLOCK_ID : 3
CORRUPT_TYPE : 1
MARKED_COR : 3
CORRUPT_DESCRIPTION : kdbchk: row locked by non-existent transaction
REPAIR_DESCRIPTION : mark block software corrupt


Step 4: Fix corrupted block


SQL> declare
fix_count int;
begin
fix_count := 0;
dbms_repair.fix_corrupt_blocks (
schema_name => 'SYSTEM',
object_name => 'T1',
object_type => dbms_repair.table_object,
repair_table_name => 'REPAIR_TABLE',
fix_count => fix_count);
dbms_output.put_line('fix count: '
to_char(fix_count));
end;
/


fix count: 1


PL/SQL procedure successfully completed.



SQL> select object_name, block_id, marked_corrupt from repair_table;


OBJECT_NAME BLOCK_ID MARKED_COR
------------------------------ ---------- ----------
T1 3 TRUE





SQL> select * from scott.t1;
select * from system.t1
*
ERROR at line 1:
ORA-01578: ORACLE data block corrupted (file # 6, block # 3)
ORA-01110: data file 6: '/tmp/ts_corrupt.dbf'


Step 5: Fix orphan keys
SQL> select index_name from dba_indexes where table_name in (select distinct object_name from repair_table);



INDEX_NAME
------------------------------
T1_PK




SQL> set serveroutput on
SQL> declare
key_count int;
begin
key_count := 0;
dbms_repair.dump_orphan_keys (
schema_name => 'SYSTEM',
object_name => 'T1_PK',
object_type => dbms_repair.index_object,
repair_table_name => 'REPAIR_TABLE',
orphan_table_name => 'ORPHAN_KEY_TABLE',
key_count => key_count);
dbms_output.put_line('orphan key count: '
to_char(key_count));
end;
/

orphan key count: 3
PL/SQL procedure successfully completed.


SQL> select index_name, count(*) from orphan_key_table group by index_name;


INDEX_NAME COUNT(*)
------------------------------ ----------
T1_PK 3


Step 5: skip corrupt block
SQL> declare
begin
dbms_repair.skip_corrupt_blocks (
schema_name => 'SCOTT',
object_name => 'T1',
object_type => dbms_repair.table_object,
flags => dbms_repair.skip_flag);
end;
/

PL/SQL procedure successfully completed.


SQL> select table_name, skip_corrupt from dba_tables where table_name = 'T1';

TABLE_NAME SKIP_COR
------------------------------ --------
T1 ENABLED


SQL> select * from scott.t1;


COL1 COL2
----------
4 dddd
5 eeee

SQL> insert into scott.t1 values (1,'aaaa');
SQL> select * from system.t1 where col1 = 1;


no rows selected

Step 5: rebuild fresslists

SQL > declare
begin
dbms_repair.rebuild_freelists (
schema_name => 'SYSTEM',
object_name => 'T1',
object_type => dbms_repair.table_object);
end;
/

PL/SQL procedure successfully completed.


Step 6: Rebuild Index

SQL> alter index scott.t1_pk rebuild online;
Index altered.



SQL> insert into system.t1 values (1, 'aaaa');
1 row created.


SQL> select * from scott.t1;


COL1 COL2
-----------
4 dddd
5 eeee
1 aaaa


Note - The above insert statement was used to provide a simple example.This is the perfect world - we know the data that was lost. The temporary table (temp_t1) should also be used to include all rows extracted from the corrupt block.