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Wednesday, April 8, 2015

OCR and Voting Disk Recovery

OCR and Voting Disk Recovery

Step #1 Stop cluster on each node (Root user).

# crsctl stop crs -f

Step #2 we are starting the cluster in the excusive mode (Root user)

As root start GI in exclusive mode on one node only:

In 11201 RAC, we have to use below option to start the cluster in the exclusive mode.

# crsctl start crs -excl

In 11202 RAC, we have to use below option to start the cluster in the exclusive mode.

# crsctl start crs -excl -nocrs

Note: A new option ‘-nocrs‘ has been introduced with  11.2.0.2, which prevents the start of the ora.crsd resource. It is vital that this option is specified; otherwise the failure to start the ora.crsd resource will tear down ora.cluster_interconnect.haip, which in turn will cause ASM to crash.

If you don’t have the OCR DISK GROUP, then we need to create the disk group else move to restoring OCR DISK


Step #3 Restoring OCR

To Know the OCR Location on the cluster environment
$ cat /etc/oracle/ocr.loc  — In Linux

To Check whether ocrcheck is corrupted or not

# ocrcheck

Check whether ocrcheck is able to complete it successfully

OCR CHECK Ex
# ocrcheck
Status of Oracle Cluster Registry is as follows :
         Version                  :          3
         Total space (kbytes)     :     262120
         Used space (kbytes)      :       4404
         Available space (kbytes) :     257716
         ID                       : 1306201859
         Device/File Name         :  +DG01
                                    Device/File integrity check succeeded
                                    Device/File not configured
                                    Device/File not configured
                                    Device/File not configured
                                    Device/File not configured
         Cluster registry integrity check succeeded

         Logical corruption check succeeded
       

Note: 1) Check whether cluster registry integrity check is successful.
          2) When you run as root user, logical corruption check will be bypassed.
If you run as oracle user, you can see this line end of the “ocrcheck” output.
“Logical corruption check bypassed due to non-privileged user”


To Know the OCR Location on the cluster environment
$ cat /etc/oracle/ocr.loc  — In Linux
If the OCR DISK corrupted, then perform the below steps

Locate OCR LOG file location
$ORACLE_HOME /log/<hostname>/client/ocrcheck_<pid>.log
Locate the latest automatic OCR backup
$GRID_HOME\bin\ocrconfig –showbackup

Restore the latest OCR backup(root user)
# ocrconfig -restore $ORACLE_HOME/cdata/testdbrac1/backup00.ocr

Step #4 Recreating Voting Disk
Recreate the Voting file (root user)
The Voting file needs to be initialized in the CRS disk group
# crsctl replace votedisk +DG01
Note: 1) Above command will Re-create/move your voting disk in the specified ASM Disk Group, if you query the voting disk it will display your voting disk location in the DISK Group which has been specified above.
2)  Voting File is  no longer supported to take a manual backup of it with dd.  Instead, the Voting File gets backed up automatically into the OCR.

Query Voting Disk location

# $ORACLE_HOME/bin/crsctl query css votedisk

Note: You cannot create more than 1 voting disk in the same or on another/different Disk group disk when using External Redundancy in 11.2. The rules are as follows:
External = 1 voting disk
Normal= 3 voting disk
High= 5 voting disk

Step #5 Stop & start the cluster

Shutdown CRS è CRS is running in exclusive mode, it needs to be shutdown (Root User).

# crsctl stop crs

Start CRS è Start the CRS in one node, if everything is ok then start the CRS in other nodes (root user).

# crsctl start crs

CRS Status è Once started, you can check the status of the CRS(Root / Oracle user)

# crsctl stat res –t –init     
# crsctl check cluster –all
# $ORACLE_HOME/bin/crsctl status resource –t


Important Tips

1) Oracle Clusterware 11g Release 2 backs up the OCR automatically every four hours on a schedule that is dependent on when the node started
4-hour backups (3 max) –backup00.ocr, backup01.ocr, and backup02.ocr.
Daily backups (2 max) – day.ocr and day_.ocr
Weekly backups (2 max) – week.ocr and week_.ocr
You can use the ocrconfig command to view the current OCR backups as seen in this

Ocrconfig –showbackup auto

Note: automatic backups will not occur, when the cluster is down
2) Verifying OCR integrity of entire cluster nodes by running CVU command:

$ cluvfy comp ocr -n all –verbose


3) Oracle Local Repository (OLR), this repository designed to store information and profiles for local resources, resources that dedicated to particular node. It improves the performance of accessing local resources profile information, redundancy and manageability. In Grid Infrastructure RAC configuration there is usual one global shared OCR and OLR’s on each node. In Oracle Restart environment there is only OLR repository. In 11g R2 there is also new feature, Grid Plug and Play (GPNP), as the name implies, it helps to automate and simplify some of the aspects of grid administration. GPNP maintains profile, it is XML file that stores the configuration information of some components maintained by GPNP, for example vips and interconnect information is stored here.

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