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Tuesday, August 7, 2012

A simple RMAN crosscheck mess up!!


Today I was attempting to rebuild a standby database as we had done some mess up with the production by placing some of the tables in "nologging" mode and relocating few datafiles due to file system space issues. It is easy to recover the standby by replacing the files from the primary and using the standby_management=manual mode to relocate the files in the standby as well. But the problem is we don't know where we started and where the situation is... Primary database is running fine after the maintenance but we lack the high availability as the standby is a day back. Hence I have decided to rebuild the standby which will take not more than 2~3 hours with a valid backup. Remember this is a database of version 10.2.0.4.0 running on Linux EL5.

Steps that has been done.

1. Backup taken from source database (Primary)
2. Backup pieces were moved to target server and the some of the backup pieces on the primary server is deleted as thinking as this DB is a 11g DB where we have feature of source database is not required to create clone. Then after realising the DB as 10g, again replaced the backups on the server.
3. Control file backup is taken for standby and transfered to the target server.

Now the actual story starts.

On target server.
RMAN> run
{
configure channel device type disk parallel 8;
duplicate target database for standby nofilenamecheck dorecover;
}
2> 3>
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-00558: error encountered while parsing input commands
RMAN-01009: syntax error: found "parallel": expecting one of: "clear, connect, debug, format, kbytes, maxopenfiles, maxpiecesize, parms, readrate, rate, send, to, trace"
RMAN-01007: at line 3 column 36 file: standard input

RMAN>
Starting Duplicate Db at 06-AUG-12
using target database control file instead of recovery catalog
allocated channel: ORA_AUX_DISK_1
channel ORA_AUX_DISK_1: sid=541 devtype=DISK
allocated channel: ORA_AUX_DISK_2
channel ORA_AUX_DISK_2: sid=540 devtype=DISK
allocated channel: ORA_AUX_DISK_3
channel ORA_AUX_DISK_3: sid=539 devtype=DISK
allocated channel: ORA_AUX_DISK_4
channel ORA_AUX_DISK_4: sid=538 devtype=DISK
allocated channel: ORA_AUX_DISK_5
channel ORA_AUX_DISK_5: sid=537 devtype=DISK

contents of Memory Script:
{
   set until scn  5170555877;
   restore clone standby controlfile;
   sql clone 'alter database mount standby database';
}
executing Memory Script
..
..
..
executing command: SET NEWNAME

executing command: SET NEWNAME

executing command: SET NEWNAME

Starting restore at 06-AUG-12
allocated channel: ORA_AUX_DISK_1
channel ORA_AUX_DISK_1: sid=537 devtype=DISK
allocated channel: ORA_AUX_DISK_2
channel ORA_AUX_DISK_2: sid=538 devtype=DISK
allocated channel: ORA_AUX_DISK_3
channel ORA_AUX_DISK_3: sid=539 devtype=DISK
allocated channel: ORA_AUX_DISK_4
channel ORA_AUX_DISK_4: sid=540 devtype=DISK
allocated channel: ORA_AUX_DISK_5
channel ORA_AUX_DISK_5: sid=541 devtype=DISK

creating datafile fno=2 name=/fs05/oradata/edisipd/edisipd_UNDOTBS_01.dbf
creating datafile fno=5 name=/fs05/oradata/edisipd/edisipd_UNDOTBS_02.dbf
creating datafile fno=8 name=/fs02/oradata/edisipd/edisipd_EDIAPP_DATA_03.dbf
creating datafile fno=15 name=/fs02/oradata/edisipd/edisipd_EDIAPP_DATA_10.dbf
creating datafile fno=17 name=/fs02/oradata/edisipd/edisipd_EDIAPP_DATA_12.dbf
creating datafile fno=18 name=/fs02/oradata/edisipd/edisipd_EDIAPP_DATA_13.dbf
creating datafile fno=19 name=/fs02/oradata/edisipd/edisipd_EDIAPP_DATA_14.dbf
creating datafile fno=23 name=/fs02/oradata/edisipd/edisipd_EDIAPP_DATA_18.dbf
..
..
..
using channel ORA_AUX_DISK_2
using channel ORA_AUX_DISK_3
using channel ORA_AUX_DISK_4
using channel ORA_AUX_DISK_5

starting media recovery

archive log thread 1 sequence 48527 is already on disk as file /fs01/oradata/edisipd/archive/edisipd_/1_724685163_48527.arc
Oracle Error:
ORA-01547: warning: RECOVER succeeded but OPEN RESETLOGS would get error below
ORA-01194: file 1 needs more recovery to be consistent
ORA-01110: data file 1: '/fs02/oradata/edisipd/edisipd_SYSTEM_01.dbf'

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of Duplicate Db command at 08/07/2012 02:49:36
RMAN-03015: error occurred in stored script Memory Script
RMAN-06053: unable to perform media recovery because of missing log
RMAN-06025: no backup of log thread 1 seq 48412 lowscn 5159567844 found to restore
RMAN-06025: no backup of log thread 1 seq 48411 lowscn 5159485436 found to restore
RMAN-06025: no backup of log thread 1 seq 48410 lowscn 5159410674 found to restore
RMAN-06025: no backup of log thread 1 seq 48409 lowscn 5159350092 found to restore
RMAN-06025: no backup of log thread 1 seq 48408 lowscn 5159263205 found to restore
Check the part where it states "creating datafile fno=...... (line numbers 56 to 63)
This is the first time I come across this statement in recovery (standby/clone) of a database. I'm not sure why it is creating file rather recovering it from the backup. I waited for sometime so that the recover completes.
Recover completes with error stating missing logs. Ok, this is expected as I don’t have some of the logs in the standby site.

Now, I started the recovery to see where the MRP stuck does, I mean which log MRP is looking for.
SQL> archive log list
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            /fs01/oradata/edisipd/archive/edisipd_
Oldest online log sequence     48550
Next log sequence to archive   0
Current log sequence           48552
SQL> select process, sequence#, status from v$managed_Standby;

PROCESS    SEQUENCE# STATUS
--------- ---------- ------------
ARCH               0 CONNECTED
ARCH               0 CONNECTED
ARCH               0 CONNECTED
ARCH               0 CONNECTED
ARCH               0 CONNECTED
RFS                0 IDLE
RFS                0 IDLE
RFS                0 IDLE
MRP0               3 WAIT_FOR_GAP

9 rows selected.
This is to my shock!! MRP is waiting for sequence number 3. Man! This is a full backup you are recovering and why in the name of God, MRP looks for sequence# 3? I have to go years back for the log sequence# 3 :-)

I thought for a second and reran the create controlfile statement on the primary database to make sure I have the correct controlfile, transferred it to standby site and started recovery after mounting the database.
SQL> recover standby database;
ORA-00279: change 310139 generated at 07/18/2010 13:52:22 needed for thread 1
ORA-00289: suggestion :
/fs01/oradata/edisipd/archive/edisipd_/1_724685163_3.arc
ORA-00280: change 310139 for thread 1 is in sequence #3


Specify log: {<ret>=suggested | filename | AUTO | CANCEL}
auto
ORA-00308: cannot open archived log
'/fs01/oradata/edisipd/archive/edisipd_/1_724685163_3.arc'
ORA-27037: unable to obtain file status
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
This again is looking for sequence# 3. So something is not right. But what is not right?
Then I checked manually myself with the backup pieces on both the servers, whether both the servers have equal number of files and their sizes. They are perfect.
Now I logged into primary database RMAN to see how many pieces have been produced while taking backup. 14 pieces have been produced and I have 14 pieces on the physical file system. So still I couldn't find what is wrong.

Now, once again I counted the number of pieces produced and got this..
RMAN> list backup tag ‘FORSTANDBY’;
..
..
..
  57      Full 5163187056 06-AUG-12 /fs04/oradata/edisipd/edisipd_EDIAPP_INDEX_12.dbf
  69      Full 5163187056 06-AUG-12 /fs05/oradata/edisipd/edisipd_EDIAPP_INDEX_24.dbf
  77      Full 5163187056 06-AUG-12 /fs06/oradata/edisipd/edisipd_EDIADT_DATA_02.dbf

BS Key  Type LVSize       Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
31223   Full    3.16G      DISK        00:28:35     06-AUG-12
        BP Key: 31464   Status: EXPIRED  Compressed: YES  Tag: FORSTANDBY
        Piece Name: /backups/stbkp/ForStandby_sknhuobu_1_1
  List of Datafiles in backup set 31223
  File LVType Ckp SCN    Ckp Time  Name
  ---- -- ---- ---------- --------- ----
  23      Full 5163317451 06-AUG-12 /fs02/oradata/edisipd/edisipd_EDIAPP_DATA_18.dbf
  25      Full 5163317451 06-AUG-12 /fs02/oradata/edisipd/edisipd_EDIAPP_DATA_20.dbf
  54      Full 5163317451 06-AUG-12 /fs04/oradata/edisipd/edisipd_EDIAPP_INDEX_09.dbf
  64      Full 5163317451 06-AUG-12 /fs05/oradata/edisipd/edisipd_EDIAPP_INDEX_19.dbf

BS Key  Type LVSize       Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
31224   Full    4.03G      DISK        00:45:33     06-AUG-12
        BP Key: 31465   Status: EXPIRED  Compressed: YES  Tag: FORSTANDBY
        Piece Name: /backups/stbkp/ForStandby_sinhunrb_1_1
  List of Datafiles in backup set 31224
  File LV Type Ckp SCN    Ckp Time  Name
  ---- -- ---- ---------- --------- ----
..
..
..
..
Some of the backup pieces were in EXPIRED status. I now remember my colleague called me today morning to inform that she moved some of the backup pieces to other file system and issued the "crosscheck backup" RMAN command when the files where deleted from primary server after transfer to standby site. After this the backup pieces were restored to the file system so the files were not cataloged to the control file.


The reason why “create datafile” is issued by RMAN is now clear. Controlfile has the details about the datafiles but the backup pieces were missing to restore/recover. Hence it creates the datafiles on the given name and it should start recover from the beginning and hence looking for sequence# 3. My confusion is now at a halt. J

Now I crosschecked the pieces once again using RMAN crosscheck command so that these pieces were cataloged to the control file. Then I started the cloning for standby which ran perfect as expected.
For the detailed steps on creating a standby database using RMAN please check the below link.

Thank you!!

2 comments:

  1. This is a user error.

    crosscheck did what it expected to.

    ReplyDelete
  2. Venky,
    I know this is an user error. But this can show lights to someone who begins on backup and recovery, just this can be as a case study. Thank you for going through my blog post and adding this as an user error. Valid point as to say!!

    ReplyDelete