Restoring a Database to a New Diskgroup

By | September 1, 2015

I had the pleasure of rebuilding an Exadata rack for a customer a while back, and it provided a pretty good refresher in backup and recovery for me.  As DBAs, we back up databases all the time, but the restores are performed much less frequently.  In the case of this rack, there were several databases across multiple ASM diskgroups.  One of the goals of the rebuild was to consolidate all of the databases into a single set of ASM diskgroups to better allow for future growth.  In the example for this post, we'll use a database named TESTER that stores files in ASM diskgroups named +DATA2 and +RECO2.  We'll take a backup, destroy the diskgroups entirely, and restore TESTER to diskgroups named +NEWDATA and +NEWRECO.  Because this exercise was a planned operation, we used cold backups of the database to perform the restore.  In most cases, you'll be performing point in time recovery on databases, and more information on that topic can be found in Oracle's documentation at http://docs.oracle.com/cd/E25054_01/backup.1111/e10642/rcmflash.htm.

In order to make matters more fun, let's say that the database has some datafiles that weren't created using Oracle's "Oracle Managed Files" (OMF) methodology.  While definitely not the best way to do things, sometimes people forget that they're using ASM and want to create datafiles with static names. For the sake of argument, let's create a datafile named "BADIDEA" in +DATA2, and one named "REALLYBAD" in +RECO2.

SQL> select tablespace_name, file_name from dba_data_files order by 1;

TABLESPACE FILE_NAME
---------- --------------------------------------------------
SYSAUX	   +DATA2/tester/datafile/sysaux.260.867618419
SYSTEM	   +DATA2/tester/datafile/system.265.867618419
UNDOTBS1   +DATA2/tester/datafile/undotbs1.264.867618419
USERS	   +DATA2/tester/datafile/users.263.867618419

SQL> create tablespace BADIDEA datafile '+DATA2/tester/BADIDEA.DBF' size 500M autoextend on next 1M;

Tablespace created.

SQL> create tablespace REALLYBAD datafile '+RECO2/tester/REALLYBAD.DBF' size 500M autoextend on next 1M;

Tablespace created.

SQL> select tablespace_name, file_name from dba_data_files order by 1;

TABLESPACE FILE_NAME
---------- --------------------------------------------------
BADIDEA    +DATA2/tester/badidea.dbf
REALLYBAD  +RECO2/tester/reallybad.dbf
SYSAUX	   +DATA2/tester/datafile/sysaux.260.867618419
SYSTEM	   +DATA2/tester/datafile/system.265.867618419
UNDOTBS1   +DATA2/tester/datafile/undotbs1.264.867618419
USERS	   +DATA2/tester/datafile/users.263.867618419

6 rows selected.

While it may seem that the datafiles here aren't using OMF, if we look inside of ASM, we will see that they actually are, and the file names that I went out of my way to create are simply pointers to the OMF datafiles.

ASMCMD> ls -l data2/tester
Type           Redund  Striped  Time             Sys  Name
                                                 N    BADIDEA.DBF => +DATA2/TESTER/DATAFILE/BADIDEA.266.867619203
                                                 Y    CONTROLFILE/
                                                 Y    DATAFILE/
                                                 Y    ONLINELOG/
                                                 Y    PARAMETERFILE/
                                                 Y    TEMPFILE/
                                                 N    spfileTESTER.ora => +DATA2/TESTER/PARAMETERFILE/spfile.256.867618495

ASMCMD> ls -l data2/tester/datafile
Type      Redund  Striped  Time             Sys  Name
DATAFILE  UNPROT  COARSE   DEC 29 21:00:00  Y    BADIDEA.266.867619203
DATAFILE  UNPROT  COARSE   DEC 29 21:00:00  Y    SYSAUX.260.867618419
DATAFILE  UNPROT  COARSE   DEC 29 21:00:00  Y    SYSTEM.265.867618419
DATAFILE  UNPROT  COARSE   DEC 29 21:00:00  Y    UNDOTBS1.264.867618419
DATAFILE  UNPROT  COARSE   DEC 29 21:00:00  Y    USERS.263.867618419

ASMCMD> ls -l reco2/tester
Type      Redund  Striped  Time             Sys  Name
                                            Y    CONTROLFILE/
                                            Y    DATAFILE/
                                            Y    ONLINELOG/
                                            N    REALLYBAD.DBF => +RECO2/TESTER/DATAFILE/REALLYBAD.260.867619207

ASMCMD> ls -l reco2/tester/datafile
Type      Redund  Striped  Time             Sys  Name
DATAFILE  UNPROT  COARSE   DEC 29 21:00:00  Y    REALLYBAD.260.867619207

Leandro Abite has an excellent script for looking at all files contained within ASM. If we run that here, we get the following output:

ASM File Name / Volume Name / Device Name						 Bytes		    Space File Type	     Creation Date	  Created?
--------------------------------------------------------------------------- ------------------ ------------------ ------------------ -------------------- --------
+DATA/ASM/ASMPARAMETERFILE/REGISTRY.253.866557445					 1,536		4,194,304   ASMPARAMETERFILE 17-DEC-2014 14:24:04    Y
									    ------------------ ------------------
											 1,536		4,194,304

+DATA2/TESTER/BADIDEA.DBF							   524,296,192	      526,385,152	    DATAFILE 29-DEC-2014 21:20:02    N
+DATA2/TESTER/CONTROLFILE/Current.262.867618463 				     9,748,480	       16,777,216	 CONTROLFILE 29-DEC-2014 21:07:42    Y
+DATA2/TESTER/DATAFILE/BADIDEA.266.867619203					   524,296,192	      526,385,152	    DATAFILE 29-DEC-2014 21:20:02    Y
+DATA2/TESTER/DATAFILE/SYSAUX.260.867618419					   492,838,912	      494,927,872	    DATAFILE 29-DEC-2014 21:06:58    Y
+DATA2/TESTER/DATAFILE/SYSTEM.265.867618419					   775,954,432	      778,043,392	    DATAFILE 29-DEC-2014 21:06:58    Y
+DATA2/TESTER/DATAFILE/UNDOTBS1.264.867618419					    31,465,472	       32,505,856	    DATAFILE 29-DEC-2014 21:06:58    Y
+DATA2/TESTER/DATAFILE/USERS.263.867618419					     5,251,072		6,291,456	    DATAFILE 29-DEC-2014 21:06:58    Y
+DATA2/TESTER/ONLINELOG/group_1.261.867618465					    52,429,312	       53,477,376	   ONLINELOG 29-DEC-2014 21:07:44    Y
+DATA2/TESTER/ONLINELOG/group_2.259.867618465					    52,429,312	       53,477,376	   ONLINELOG 29-DEC-2014 21:07:44    Y
+DATA2/TESTER/ONLINELOG/group_3.258.867618465					    52,429,312	       53,477,376	   ONLINELOG 29-DEC-2014 21:07:44    Y
+DATA2/TESTER/PARAMETERFILE/spfile.256.867618495					 2,560		1,048,576      PARAMETERFILE 29-DEC-2014 21:08:15    Y
+DATA2/TESTER/TEMPFILE/TEMP.257.867618465					    20,979,712	       22,020,096	    TEMPFILE 29-DEC-2014 21:07:45    Y
+DATA2/TESTER/spfileTESTER.ora								 2,560		1,048,576      PARAMETERFILE 29-DEC-2014 21:08:15    N
									    ------------------ ------------------
										 2,542,123,520	    2,565,865,472

+RECO2/TESTER/CONTROLFILE/Current.256.867618463 				     9,748,480	       16,777,216	 CONTROLFILE 29-DEC-2014 21:07:42    Y
+RECO2/TESTER/DATAFILE/REALLYBAD.260.867619207					   524,296,192	      526,385,152	    DATAFILE 29-DEC-2014 21:20:07    Y
+RECO2/TESTER/ONLINELOG/group_1.259.867618465					    52,429,312	       53,477,376	   ONLINELOG 29-DEC-2014 21:07:44    Y
+RECO2/TESTER/ONLINELOG/group_2.258.867618465					    52,429,312	       53,477,376	   ONLINELOG 29-DEC-2014 21:07:44    Y
+RECO2/TESTER/ONLINELOG/group_3.257.867618465					    52,429,312	       53,477,376	   ONLINELOG 29-DEC-2014 21:07:44    Y
+RECO2/TESTER/REALLYBAD.DBF							   524,296,192	      526,385,152	    DATAFILE 29-DEC-2014 21:20:07    N
									    ------------------ ------------------
										 1,215,628,800	    1,229,979,648

									    ------------------ ------------------
Grand Total:									 3,757,753,856	    3,800,039,424

If you look closer at the non-OMF files that were created earlier, you will notice that they are listed twice in the output. The pointer is flagged as "N" in the final column (which represents automatically created files). Keep that in mind when looking at the space utilization...or just don't create non-OMF files on ASM. That's probably a better idea.

Anyway, on to the meat of the topic at hand. Because this was a planned backup/restore, I was smart enough to get backups of everything, including the password and parameter files. I created a pfile from the spfile that was in use, and copied that (along with the password file) over to my NFS share.

SQL> create pfile='/backup/tester/initTESTER.ora' from spfile;

File created.

SQL> !cp -ax $ORACLE_HOME/dbs/orapwTESTER /backup/tester/orapwTESTER

Next, it was time to take the database backup. I shut the database down, started it in a mounted state, and took a full backup including the controlfile. I'm using tee to make sure that everything is logged. This is important, because we will want to keep things like the DBID consistent after we restore the database. I'm including a "report schema" for good measure so that we can compare final results.

[oracle@localhost ~]$ rman target / | tee /backup/tester/backup_tester.log

Recovery Manager: Release 11.2.0.4.0 - Production on Mon Dec 29 21:41:40 2014

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

connected to target database: TESTER (DBID=3545964190)

RMAN> shutdown immediate;

using target database control file instead of recovery catalog
database closed
database dismounted
Oracle instance shut down

RMAN> startup mount;

connected to target database (not started)
Oracle instance started
database mounted

Total System Global Area     601272320 bytes

Fixed Size                     2255592 bytes
Variable Size                230688024 bytes
Database Buffers             360710144 bytes
Redo Buffers                   7618560 bytes

RMAN> run {
2> allocate channel d1 device type disk format '/backup/tester/tester_arch_%U';
3> backup archivelog all delete input;
4> release channel d1;
5> allocate channel d1 device type disk format '/backup/tester/tester_db_%U';
6> backup database include current controlfile;
7> release channel d1;
8> report schema;
9> }

allocated channel: d1
channel d1: SID=14 device type=DISK

Starting backup at 29-DEC-14
specification does not match any archived log in the repository
backup cancelled because there are no files to backup
Finished backup at 29-DEC-14

released channel: d1

allocated channel: d1
channel d1: SID=14 device type=DISK

Starting backup at 29-DEC-14
channel d1: starting full datafile backup set
channel d1: specifying datafile(s) in backup set
input datafile file number=00001 name=+DATA2/tester/datafile/system.265.867618419
input datafile file number=00005 name=+DATA2/tester/badidea.dbf
input datafile file number=00006 name=+RECO2/tester/reallybad.dbf
input datafile file number=00002 name=+DATA2/tester/datafile/sysaux.260.867618419
input datafile file number=00003 name=+DATA2/tester/datafile/undotbs1.264.867618419
input datafile file number=00004 name=+DATA2/tester/datafile/users.263.867618419
channel d1: starting piece 1 at 29-DEC-14
channel d1: finished piece 1 at 29-DEC-14
piece handle=/backup/tester/tester_db_01prdln0_1_1 tag=TAG20141229T214255 comment=NONE
channel d1: backup set complete, elapsed time: 00:00:15
channel d1: starting full datafile backup set
channel d1: specifying datafile(s) in backup set
including current control file in backup set
including current SPFILE in backup set
channel d1: starting piece 1 at 29-DEC-14
channel d1: finished piece 1 at 29-DEC-14
piece handle=/backup/tester/tester_db_02prdlnf_1_1 tag=TAG20141229T214255 comment=NONE
channel d1: backup set complete, elapsed time: 00:00:01
Finished backup at 29-DEC-14

released channel: d1

Report of database schema for database with db_unique_name TESTER

List of Permanent Datafiles
===========================
File Size(MB) Tablespace           RB segs Datafile Name
---- -------- -------------------- ------- ------------------------
1    740      SYSTEM               ***     +DATA2/tester/datafile/system.265.867618419
2    470      SYSAUX               ***     +DATA2/tester/datafile/sysaux.260.867618419
3    30       UNDOTBS1             ***     +DATA2/tester/datafile/undotbs1.264.867618419
4    5        USERS                ***     +DATA2/tester/datafile/users.263.867618419
5    500      BADIDEA              ***     +DATA2/tester/badidea.dbf
6    500      REALLYBAD            ***     +RECO2/tester/reallybad.dbf

List of Temporary Files
=======================
File Size(MB) Tablespace           Maxsize(MB) Tempfile Name
---- -------- -------------------- ----------- --------------------
1    20       TEMP                 32767       +DATA2/tester/tempfile/temp.257.867618465

Because this is a very small database with no actual contents, the backup script only uses one channel. The important things to know are that we have a consistent backup that includes the control file. Let's take a look at the backup sets that are now listed:

RMAN> list backupset;

using target database control file instead of recovery catalog

List of Backup Sets
===================


BS Key  Type LV Size       Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
1       Full    1016.39M   DISK        00:00:09     29-DEC-14
        BP Key: 1   Status: AVAILABLE  Compressed: NO  Tag: TAG20141229T214255
        Piece Name: /backup/tester/tester_db_01prdln0_1_1
  List of Datafiles in backup set 1
  File LV Type Ckp SCN    Ckp Time  Name
  ---- -- ---- ---------- --------- ----
  1       Full 933446     29-DEC-14 +DATA2/tester/datafile/system.265.867618419
  2       Full 933446     29-DEC-14 +DATA2/tester/datafile/sysaux.260.867618419
  3       Full 933446     29-DEC-14 +DATA2/tester/datafile/undotbs1.264.867618419
  4       Full 933446     29-DEC-14 +DATA2/tester/datafile/users.263.867618419
  5       Full 933446     29-DEC-14 +DATA2/tester/badidea.dbf
  6       Full 933446     29-DEC-14 +RECO2/tester/reallybad.dbf

BS Key  Type LV Size       Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
2       Full    9.36M      DISK        00:00:03     29-DEC-14
        BP Key: 2   Status: AVAILABLE  Compressed: NO  Tag: TAG20141229T214255
        Piece Name: /backup/tester/tester_db_02prdlnf_1_1
  SPFILE Included: Modification time: 29-DEC-14
  SPFILE db_unique_name: TESTER
  Control File Included: Ckp SCN: 933446       Ckp time: 29-DEC-14

Backupset #1 contains all of the datafiles, and backupset #2 contains the control file. It's important to remember these piece names and have a backup listing when we perform the restore. Now that we have a good backup, it's time to trash the ASM diskgroups!

SQL> drop diskgroup DATA2 including contents;

Diskgroup dropped.

SQL> drop diskgroup RECO2 including contents;

Diskgroup dropped.

SQL> CREATE DISKGROUP NEWDATA
  2    EXTERNAL REDUNDANCY
  3    DISK '/dev/oracleasm/disks/ASM3'
  4    ATTRIBUTE
  5    'AU_SIZE'='1M',
  6    'compatible.asm' = '11.2.0.2.0',
  7    'compatible.rdbms' = '11.2.0.2.0'
  8  /

Diskgroup created.

SQL> CREATE DISKGROUP NEWRECO
  2    EXTERNAL REDUNDANCY
  3    DISK '/dev/oracleasm/disks/ASM2'
  4    ATTRIBUTE
  5    'AU_SIZE'='1M',
  6    'compatible.asm' = '11.2.0.2.0',
  7    'compatible.rdbms' = '11.2.0.2.0'
  8  /

Diskgroup created.

SQL> @asm_diskgroups

Diskgroup  Sector Size AU Size (MB) State	Redundancy    Size (MB)    Free (MB)  Usable (MB)
---------- ----------- ------------ ----------- ---------- ------------ ------------ ------------
DATA		   512		  4 MOUNTED	EXTERN		 10,236       10,148
NEWDATA 	   512		  1 MOUNTED	EXTERN		 10,236       10,184
NEWRECO 	   512		  1 MOUNTED	EXTERN		 10,236       10,184

After dropping the diskgroups, I created new diskgroups, swapping the disks that were used (+DATA2 was on /dev/oracleasm/disks/ASM2 and +RECO2 was on /dev/oracleasm/disks/ASM3). We can see that there are now diskgroups named +NEWDATA and +NEWRECO.

At this point, we are ready to begin the database restore process. First, copy the password file back over to $ORACLE_HOME/dbs, and modify the control_files, db_create_file_dest, and db_recovery_file_dest parameters to reflect the new diskgroup names. Also, be sure to create the directory listed in audit_file_dest in case it was previously lost. Here's the full contents of my initTESTER.ora:

[oracle@localhost ~]$ cat /backup/tester/initTESTER.ora
TESTER.__db_cache_size=423624704
TESTER.__java_pool_size=4194304
TESTER.__large_pool_size=8388608
TESTER.__pga_aggregate_target=201326592
TESTER.__sga_target=603979776
TESTER.__shared_io_pool_size=0
TESTER.__shared_pool_size=155189248
TESTER.__streams_pool_size=0
*.audit_file_dest='/u01/app/oracle/admin/TESTER/adump'
*.audit_trail='db'
*.compatible='11.2.0.4.0'
*.control_files='+NEWDATA/tester/controlfile/current.262.867618463','+NEWRECO/tester/controlfile/current.256.867618463'
*.db_block_size=8192
*.db_create_file_dest='+NEWDATA'
*.db_domain=''
*.db_name='TESTER'
*.db_recovery_file_dest='+NEWRECO'
*.db_recovery_file_dest_size=4385144832
*.diagnostic_dest='/u01/app/oracle'
*.dispatchers='(PROTOCOL=TCP) (SERVICE=TESTERXDB)'
*.log_archive_format='%t_%s_%r.dbf'
*.open_cursors=300
*.pga_aggregate_target=201326592
*.processes=150
*.remote_login_passwordfile='EXCLUSIVE'
*.sga_target=603979776
*.undo_tablespace='UNDOTBS1'

I left the file names as-is in the control_files parameter setting and only changed the diskgroup names. When we restore the control file, it will generate new OMF file names.

Next, we can start the database in nomount state:

[oracle@localhost ~]$ rman target / | tee /backup/tester/restore1_tester.log

Recovery Manager: Release 11.2.0.4.0 - Production on Mon Dec 29 22:16:23 2014

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

connected to target database (not started)

RMAN> set dbid 3545964190;

executing command: SET DBID

RMAN> startup nomount pfile='/backup/tester/initTESTER.ora';

Oracle instance started

Total System Global Area     601272320 bytes

Fixed Size                     2255592 bytes
Variable Size                230688024 bytes
Database Buffers             360710144 bytes
Redo Buffers                   7618560 bytes

RMAN> restore controlfile from '/backup/tester/tester_db_02prdlnf_1_1';

Starting restore at 29-DEC-14
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=137 device type=DISK

channel ORA_DISK_1: restoring control file
channel ORA_DISK_1: restore complete, elapsed time: 00:00:01
output file name=+NEWDATA/tester/controlfile/current.256.867660489
output file name=+NEWRECO/tester/controlfile/current.256.867660489
Finished restore at 29-DEC-14

RMAN> exit

In the commands above, we set the DBID and start the database from the pfile that was created originally. Once the database was started in nomount state, the control file was restored to the +NEWDATA and +NEWRECO diskgroups. These values came from the pfile that was used to start the database. Next, take the names of the new control files and place those inside the pfile.

[oracle@localhost ~]$ grep control /backup/tester/initTESTER.ora
*.control_files='+NEWDATA/tester/controlfile/current.256.867660489','+NEWRECO/tester/controlfile/current.256.867660489'

Now that the correct control files are being used in the pfile, start the database again in a mounted state and restore the backups. Inside of the restore command, the "set newname for database" command is issued. This is the command that tells the database to use the new diskgroup names. First, we restart the database (mounted) using the modified pfile and issue the restore command.

[oracle@localhost ~]$ rman target / | tee /backup/tester/restore2_tester.log

Recovery Manager: Release 11.2.0.4.0 - Production on Tue Dec 30 08:55:56 2014

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

connected to target database: TESTER (not mounted)

RMAN> shutdown immediate;

using target database control file instead of recovery catalog
Oracle instance shut down

RMAN> startup mount pfile='/backup/tester/initTESTER.ora';

connected to target database (not started)
Oracle instance started
database mounted

Total System Global Area     601272320 bytes

Fixed Size                     2255592 bytes
Variable Size                230688024 bytes
Database Buffers             360710144 bytes
Redo Buffers                   7618560 bytes

RMAN> run {
2> set newname for database to '+NEWDATA';
3> restore database;
4> switch datafile all;
5> alter database open resetlogs;
6> }

executing command: SET NEWNAME

Starting restore at 30-DEC-14
Starting implicit crosscheck backup at 30-DEC-14
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=14 device type=DISK
Crosschecked 1 objects
Finished implicit crosscheck backup at 30-DEC-14

Starting implicit crosscheck copy at 30-DEC-14
using channel ORA_DISK_1
Finished implicit crosscheck copy at 30-DEC-14

searching for all files in the recovery area
cataloging files...
no files cataloged

using channel ORA_DISK_1

channel ORA_DISK_1: starting datafile backup set restore
channel ORA_DISK_1: specifying datafile(s) to restore from backup set
channel ORA_DISK_1: restoring datafile 00001 to +NEWDATA
channel ORA_DISK_1: restoring datafile 00002 to +NEWDATA
channel ORA_DISK_1: restoring datafile 00003 to +NEWDATA
channel ORA_DISK_1: restoring datafile 00004 to +NEWDATA
channel ORA_DISK_1: restoring datafile 00005 to +NEWDATA
channel ORA_DISK_1: restoring datafile 00006 to +NEWDATA
channel ORA_DISK_1: reading from backup piece /backup/tester/tester_db_01prdln0_1_1
channel ORA_DISK_1: piece handle=/backup/tester/tester_db_01prdln0_1_1 tag=TAG20141229T214255
channel ORA_DISK_1: restored backup piece 1
channel ORA_DISK_1: restore complete, elapsed time: 00:00:07
Finished restore at 30-DEC-14

datafile 1 switched to datafile copy
input datafile copy RECID=7 STAMP=867661005 file name=+NEWDATA/tester/datafile/system.257.867660999
datafile 2 switched to datafile copy
input datafile copy RECID=8 STAMP=867661005 file name=+NEWDATA/tester/datafile/sysaux.260.867660999
datafile 3 switched to datafile copy
input datafile copy RECID=9 STAMP=867661005 file name=+NEWDATA/tester/datafile/undotbs1.261.867660999
datafile 4 switched to datafile copy
input datafile copy RECID=10 STAMP=867661005 file name=+NEWDATA/tester/datafile/users.262.867660999
datafile 5 switched to datafile copy
input datafile copy RECID=11 STAMP=867661005 file name=+NEWDATA/tester/datafile/badidea.258.867660999
datafile 6 switched to datafile copy
input datafile copy RECID=12 STAMP=867661005 file name=+NEWDATA/tester/datafile/reallybad.259.867660999

database opened

RMAN>

About the alter database open resetlogs command - we have to open the database with resetlogs because the control files were restored from a backup. There is no other way to just open the database, even if a cold backup was taken. Further, the redo logs were lost when the diskgroups were destroyed. When the "alter database open resetlogs" command is issued, new redologs will be created in the desired location. Finally, create the spfile in ASM from the pfile that was originally used.
 

Final comment, please don't judge me for using ASMlib - it's a terrible habit that I'll shake from my VMs some day 🙂

2 thoughts on “Restoring a Database to a New Diskgroup

  1. Jakub Wartak

    “Final comment, please don’t judge me for using ASMlib” – you are not using it, you are using /dev/oracleasm/ paths instead of ORCL:* or maybe you wanted to say “don’t judge me for **not** using ASMLib”, either way you are getting some enemies 😉

    Reply
  2. Weidong Zhou

    Hi, Andy,
    Nice writeup. Your example is using cold backup. I guess this is the reason you didn’t include “recover database” command in the recovery script. For large database, you might not have the luxury to do a cold backup in production. It might be a good idea to include this command, just to cover hot backup scenario.
    Weidong

    Reply

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