Add ASM disks to exiting ASM disk group and monitoring Re balancing operation :-
Extending and Existing DISK GROUP :-
ASM automatically re balances the disk group when disk are added By default the Alter disk group statement returns immediately after the disk have been added while the re balance operation continues to run asynchronously.you can query the V$ASM_OPERATION view to monitor the status of the re balance operation
You can optionally use the RE BALANCE clause to manually control the re balance process. In the POWER clause,you can specify a value from 0 to 11.A value of 0 disable re balancing for this statement.A value of 1 causes the re balance to take place with minimal resources allocated to it.whereas a value of 11 permits ASM to execute the re balance to the value of the ASM_POWER_LIMIT initialization parameter .
Dropping Disks from an existing DISK group :
When a disk is dropped. The disk group is re balanced by moving all the file extents from the dropped disk to other disks in the disk group .A drop disk operation will fail if not enough space is available on the other disk.Data will not be lost by dropping a disk . By default the alter disk group …. Drop disk statement returns before the drop and re balances operations are complete.Do not reuse,remove or disconnect the dropped disk until the HEADER_STATUS column for this disk in the v$ASM_DISK view changes to FORMER.You can query the v$ASM_OPERATION view to determine the amount of the time remaining for the drop/rebalance operation to complete .
DISK_GROUP_NAME DISK_FILE_PATH DISK_FILE_NAME DISK_FILE_FAIL_GROUP HEADER_STATU
-------------------- ------------------------- ------------------------------ ------------------------------ ------------
DATA ORCL:DATA1 DATA1 DATA1 MEMBER
DATA ORCL:DATA3 DATA3 DATA3 MEMBER
DATA ORCL:DATA2 DATA2 DATA2 MEMBER
OCRVOTE ORCL:OCR_VOTE3 OCR_VOTE3 OCR_VOTE3 MEMBER
OCRVOTE ORCL:OCR_VOTE1 OCR_VOTE1 OCR_VOTE1 MEMBER
OCRVOTE ORCL:OCR_VOTE2 OCR_VOTE2 OCR_VOTE2 MEMBER
[CANDIDATE] ORCL:OCR_VOTE4 PROVISIONED
[CANDIDATE] ORCL:OCR_VOTE5 PROVISIONED
[CANDIDATE] ORCL:FRA3 PROVISIONED
[CANDIDATE] ORCL:FRA2 PROVISIONED
[CANDIDATE] ORCL:FRA1 FORMER
HEADER_STATUS column status for disk
MEMBER - Member status shows disk is part of ASM disk group .
PROVISIONED - PROVISIONED status show , we can add this disk in disk group
Former - Former status show disk was part of our disk group
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1) To find out ASM disk to which need to add in exiting disk group
set linesize 200
col DISK_GROUP_NAME format a20;
col DISK_FILE_PATH format a25;
SELECT
NVL(a.name, '[CANDIDATE]') disk_group_name
, b.path disk_file_path
, b.name disk_file_name
, b.failgroup disk_file_fail_group
,b.header_status
FROM
v$asm_diskgroup a RIGHT OUTER JOIN v$asm_disk b USING (group_number)
ORDER BY a.name;
DISK_GROUP_NAME DISK_FILE_PATH DISK_FILE_NAME DISK_FILE_FAIL_GROUP HEADER_STATU
-------------------- ------------------------- ------------------------------ ------------------------------ ------------
DATA ORCL:DATA1 DATA1 DATA1 MEMBER
DATA ORCL:DATA3 DATA3 DATA3 MEMBER
DATA ORCL:DATA2 DATA2 DATA2 MEMBER
OCRVOTE ORCL:OCR_VOTE3 OCR_VOTE3 OCR_VOTE3 MEMBER
OCRVOTE ORCL:OCR_VOTE1 OCR_VOTE1 OCR_VOTE1 MEMBER
OCRVOTE ORCL:OCR_VOTE2 OCR_VOTE2 OCR_VOTE2 MEMBER
[CANDIDATE] ORCL:OCR_VOTE4 PROVISIONED
[CANDIDATE] ORCL:OCR_VOTE5 PROVISIONED
[CANDIDATE] ORCL:FRA3 PROVISIONED
[CANDIDATE] ORCL:FRA2 PROVISIONED
[CANDIDATE] ORCL:FRA1 FORMER
2) To check the diskgroup size
select name, STATE,TOTAL_MB/1024 "Total GB",USABLE_FILE_MB/1024 "Free GB",(USABLE_FILE_MB/TOTAL_MB)*100 "% Free",TYPE from v$asm_diskgroup;
NAME STATE Total GB Free GB % Free TYPE
-------- ----------- ---------- ---------- ---------- ------
OCRVOTE MOUNTED 13.9951172 6.39453125 45.691159 NORMAL
DATA MOUNTED 83.8330078 39.2246094 46.7889801 NORMAL
3) Add the disk in disk group off business hours then only you can start the re balancing operation .
Login to ASM instance
# sqlplus "/ sys as sysasm"
Then perform the below command .
alter diskgroup DATA ADD DISK 'ORCL:FRA1' rebalance power 4 ;
4) Monitor the re-balancing operation from the sql prompt .
SQL> select INST_ID, OPERATION, STATE, POWER, SOFAR, EST_WORK, EST_RATE, EST_MINUTES from GV$ASM_OPERATION;
INST_ID OPERA STAT POWER SOFAR EST_WORK EST_RATE EST_MINUTES
---------- ----- ---- ---------- ---------- ---------- ---------- -----------
2 REBAL RUN 4 3 1 208 240 5
1 REBAL WAIT 4
Monitoring the re-balancing operation from ASMCMD prompt
[oracle@india2 ~]$ asmcmd
ASMCMD> lsop
Group_Name Dsk_Num State Power
DATA REBAL RUN 4
5) Validate the disk is added in disk group or not .
set linesize 200
col DISK_GROUP_NAME format a20;
col DISK_FILE_PATH format a25;
SELECT
NVL(a.name, '[CANDIDATE]') disk_group_name
, b.path disk_file_path
, b.name disk_file_name
, b.failgroup disk_file_fail_group
,b.header_status
FROM
v$asm_diskgroup a RIGHT OUTER JOIN v$asm_disk b USING (group_number)
ORDER BY a.name;
====================================================
Monitoring ASM alert log file while adding disk in exiting disk group
===============================================================
Added disk in the existing diskgroup and asm instance alert output
Asm alert logfile location --- /u01/app/oracle/diag/asm/+asm/+ASM1/trace
alter diskgroup DATA ADD DISK 'ORCL:FRA1' rebalance power 4
=========================================================================
SQL> alter diskgroup DATA ADD DISK 'ORCL:FRA1' rebalance power 4
NOTE: GroupBlock outside rolling migration privileged region
NOTE: Assigning number (1,3) to disk (ORCL:FRA1)
NOTE: requesting all-instance membership refresh for group=1
NOTE: initializing header on grp 1 disk FRA1
NOTE: requesting all-instance disk validation for group=1
Sat Mar 25 08:32:09 2017
NOTE: skipping rediscovery for group 1/0x34570003 (DATA) on local instance.
NOTE: requesting all-instance disk validation for group=1
NOTE: skipping rediscovery for group 1/0x34570003 (DATA) on local instance.
Sat Mar 25 08:32:13 2017
GMON updating for reconfiguration, group 1 at 7 for pid 28, osid 19375
NOTE: group 1 PST updated.
NOTE: initiating PST update: grp = 1
GMON updating group 1 at 8 for pid 28, osid 19375
NOTE: PST update grp = 1 completed successfully
NOTE: membership refresh pending for group 1/0x34570003 (DATA)
GMON querying group 1 at 9 for pid 18, osid 8853
NOTE: cache opening disk 3 of grp 1: FRA1 label:FRA1
NOTE: Attempting voting file refresh on diskgroup DATA
NOTE: Refresh completed on diskgroup DATA. No voting file found.
GMON querying group 1 at 10 for pid 18, osid 8853
SUCCESS: refreshed membership for 1/0x34570003 (DATA)
Sat Mar 25 08:32:18 2017
SUCCESS: alter diskgroup DATA ADD DISK 'ORCL:FRA1' rebalance power 4
NOTE: starting rebalance of group 1/0x34570003 (DATA) at power 4
Starting background process ARB0
Sat Mar 25 08:32:18 2017
ARB0 started with pid=34, OS id=22674
NOTE: assigning ARB0 to group 1/0x34570003 (DATA) with 4 parallel I/Os
cellip.ora not found.
Sat Mar 25 08:32:48 2017
NOTE: Attempting voting file refresh on diskgroup DATA
NOTE: Refresh completed on diskgroup DATA. No voting file found.
Sat Mar 25 08:36:54 2017
NOTE: GroupBlock outside rolling migration privileged region
NOTE: requesting all-instance membership refresh for group=1
Sat Mar 25 08:36:57 2017
NOTE: membership refresh pending for group 1/0x34570003 (DATA)
Sat Mar 25 08:37:01 2017
GMON querying group 1 at 11 for pid 18, osid 8853
Sat Mar 25 08:37:09 2017
SUCCESS: refreshed membership for 1/0x34570003 (DATA)
NOTE: Attempting voting file refresh on diskgroup DATA
NOTE: Refresh completed on diskgroup DATA. No voting file found.
Sat Mar 25 08:40:04 2017
NOTE: stopping process ARB0
SUCCESS: rebalance completed for group 1/0x34570003 (DATA)
=================================================================
How to drop the disk from the exiting disk group , How to add disk with re-balance 0 option and other ASM topic , I will publish in next post .
Thanks
Srinivasa
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