Altering Disk Groups
You can alter a disk group with SQL*Plus, ASMCA, or ASMCMD commands.
You can use the ALTER
DISKGROUP
SQL statement to alter a disk group configuration. You can also alter a disk group configuration with Oracle ASM Configuration Assistant (ASMCA) and the ASMCMD chdg
command.
You can add, resize, or drop disks while the database remains online. Whenever possible, multiple operations in a single ALTER
DISKGROUP
statement are recommended. Grouping operations in a single ALTER
DISKGROUP
statement can reduce rebalancing operations.
Oracle ASM automatically rebalances when the configuration of a disk group changes. By default, the ALTER
DISKGROUP
statement does not wait until the operation is complete before returning. Query the V$ASM_OPERATION
view to monitor the status of this operation.
Use the REBALANCE
WAIT
clause to cause the ALTER
DISKGROUP
statement processing to wait until the rebalance operation is complete before returning. This is especially useful in scripts. The statement also accepts a REBALANCE
NOWAIT
clause that invokes the default behavior of conducting the rebalance operation asynchronously in the background.
You can interrupt a rebalance running in wait mode by typing CTRL+C
on most platforms. This causes the statement to return immediately with the message ORA-01013: user requested cancel of current operation
, and then to continue the operation asynchronously. Typing CTRL+C
does not cancel the rebalance operation or any disk add, drop, or resize operations.
To control the speed and resource consumption of the rebalance operation, you can include the REBALANCE
POWER
clause in statements that add, drop, or resize disks.
The following topics are discussed:
See Also:
-
Managing Disk Groups with ASMCA for information about altering a disk group configuration with Oracle ASM Configuration Assistant (ASMCA)
-
chdg for information about altering a disk group configuration with ASMCMD
chdg
-
Manually Rebalancing Disk Groups for more information about the
REBALANCE
POWER
clause -
Oracle Database SQL Language Reference for information about the
ALTER
DISKGROUP
SQL statement
Managing Oracle ADVM Volumes in a Disk Group
You can create an Oracle ASM Dynamic Volume Manager (Oracle ADVM) volume in a disk group.
The volume device associated with the dynamic volume can be used to host an Oracle ACFS file system.
The compatibility attributes COMPATIBLE.ASM
and COMPATIBLE.ADVM
must be set to 11.2
or higher for the disk group.
The ALTER
DISKGROUP
VOLUME
SQL statements enable you to manage Oracle ADVM volumes, including the functionality to add, modify, resize, disable, enable, and drop volumes.
If the Oracle ADVM volume is on a flex disk group, then you can change the redundancy of the Oracle ADVM volume online with the ALTER
DISKGROUP
MODIFY
FILEGROUP
volume_name
SQL statement.
Note:
If the volume is hosting an Oracle ACFS file system, then you cannot resize that volume with the SQL ALTER
DISKGROUP
statement. You must use the acfsutil
size
command instead.
The following are examples of the ALTER
DISKGROUP
VOLUME
statement.
Example 4-5 Managing volumes with ALTER DISKGROUP VOLUME statements
SQL> ALTER DISKGROUP data ADD VOLUME volume1 SIZE 10G; Diskgroup altered. SQL> ALTER DISKGROUP data RESIZE VOLUME volume1 SIZE 15G; Diskgroup altered. SQL> ALTER DISKGROUP data DISABLE VOLUME volume1; Diskgroup altered. SQL> ALTER DISKGROUP data ENABLE VOLUME volume1; Diskgroup altered. SQL> ALTER DISKGROUP ALL DISABLE VOLUME ALL; Diskgroup altered. SQL> ALTER DISKGROUP data DROP VOLUME volume1; Diskgroup altered.
See Also:
-
Disk Group Compatibility Attributes for information about disk group compatibility attributes
-
acfsutil size for information about the resizing a volume with
acfsutil
size
-
Overview of Oracle ASM Dynamic Volume Manager for information about Oracle ADVM
-
Managing Oracle ADVM with ASMCMD for information about managing Oracle ADVM volumes with ASMCMD
-
ASMCA GUI Tool for Managing Oracle ACFS and Oracle ADVM for information about managing Oracle ADVM volumes with ASMCA
-
About Oracle ASM File Group Properties for information about file group properties
-
Oracle Database SQL Language Reference for information about the
ALTER
DISKGROUP
SQL statement
Adding Disks to a Disk Group
You can use the ADD
clause of the ALTER
DISKGROUP
statement to add a disk or a failure group to a disk group.
You can use the same syntax with the ALTER DISKGROUP
statement that you use to add a disk or failure group with the CREATE
DISKGROUP
statement. After you add new disks, the new disks gradually begin to accommodate their share of the workload as rebalancing progresses.
When adding a disk, the disk must be the same size as the other disks in the disk group.
See Also:
-
Example 4-1 for an example of the
CREATE
DISKGROUP
SQL statement -
Using the ALTER DISKGROUP SQL Statement to Add Disks to a Disk Group for an example of using SQL statements to add disks to a disk group
-
Managing Disk Groups with ASMCA for information about adding disks to a disk group with ASMCA
-
Oracle Database SQL Language Reference for information about the
ALTER
DISKGROUP
SQL statement
Using the ALTER DISKGROUP SQL Statement to Add Disks to a Disk Group
The SQL statements presented in the following example demonstrate the interactions of disk discovery with the ADD
DISK
operation.
Assume that disk discovery identifies the following disks in directory /devices
:
/devices/diska1 -- member of data1 /devices/diska2 -- member of data1 /devices/diska3 -- member of data1 /devices/diska4 -- member of data1 /devices/diska5 -- candidate disk /devices/diska6 -- candidate disk /devices/diska7 -- candidate disk /devices/diska8 -- candidate disk /devices/diskb1 -- member of data1 /devices/diskb2 -- member of data1 /devices/diskb3 -- member of data1 /devices/diskb4 -- member of data2 /devices/diskc1 -- member of data2 /devices/diskc2 -- member of data2 /devices/diskc3 -- member of data3 /devices/diskc4 -- candidate disk /devices/diskd1 -- candidate disk /devices/diskd2 -- candidate disk /devices/diskd3 -- candidate disk /devices/diskd4 -- candidate disk /devices/diskd5 -- candidate disk /devices/diskd6 -- candidate disk /devices/diskd7 -- candidate disk /devices/diskd8 -- candidate disk
You can query the V$ASM_DISK
view to display the status of Oracle ASM disks. See "Views Containing Oracle ASM Disk Group Information".
The following statement would fail because /devices/diska1
through /devices/diska4
currently belong to the disk group data1
.
ALTER DISKGROUP data1 ADD DISK '/devices/diska*';
The following statement successfully adds disks /devices/diska5
through /devices/diska8
to data1
. Because no FAILGROUP
clauses are included in the ALTER DISKGROUP
statement, each disk is assigned to its own failure group. The NAME
clauses assign names to the disks, otherwise they would have been assigned system-generated names.
ALTER DISKGROUP data1 ADD DISK '/devices/diska5' NAME diska5, '/devices/diska6' NAME diska6, '/devices/diska7' NAME diska7, '/devices/diska8' NAME diska8;
The following statement would fail because the search string matches disks that are contained in other disk groups. Specifically, /devices/diska4
belongs to disk group data1
and /devices/diskb4
belongs to disk group data2
.
ALTER DISKGROUP data1 ADD DISK '/devices/disk*4';
The following statement would successfully add /devices/diskd1
through /devices/diskd8
to disk group data1
. This statement runs with a rebalance power of 5, and does not return until the rebalance operation is complete.
ALTER DISKGROUP data1 ADD DISK '/devices/diskd*' REBALANCE POWER 5 WAIT;
If /devices/diskc3
was previously a member of a disk group that no longer exists, then you could use the FORCE
option to add the disk as a member of another disk group. For example, the following use of the FORCE
clause enables /devices/diskc3
to be added to data2
, even though it is a current member of data3
. For this statement to succeed, data3
cannot be mounted.
ALTER DISKGROUP data2 ADD DISK '/devices/diskc3' FORCE;
Replacing Disks in Disk Groups
A disk or multiple disks in a disk group can be replaced, rather than dropped and added back.
The single replace operation is more efficient than dropping and adding disks. This operation is especially useful when disks are missing or damaged.
For example, you can issue the following statement to replace the diskc7
disk with another disk identified by the /devices/diskc18
path.
SQL> ALTER DISKGROUP data2 REPLACE DISK diskc7 WITH '/devices/diskc18' POWER 3;
The power option operates the same as the power option for the ALTER
DISKGROUP
REBALANCE
statement, except that the power option cannot be set to 0
.
The ALTER
DISKGROUP
SQL statement with the REPLACE
clause includes a WAIT
or NOWAIT
option, plus the FORCE
option.
Note:
-
Manually Rebalancing Disk Groups for information about the power option in rebalancing a disk group
-
ASM_POWER_LIMIT for information about the
ASM_POWER_LIMIT
initialization parameter
Renaming Disks in Disk Groups
You can rename a disk in a disk group with the ALTER
DISKGROUP
RENAME
DISK
SQL statement.
Note:
You can only use theRENAME
DISK
operation when the disk group that contains the disk is in the MOUNT
RESTRICTED
state. If any disks in the disk group are offline, then the RENAME
operation fails. If the new disk name exists, then the RENAME
operation fails. You must have SYSASM
privileges to rename a disk.
In one SQL statement, you can rename one or multiple disks, or rename all disks in a disk group using the RENAME
DISKS
ALL
clause.
For example, you can rename disks as follows:
SQL> ALTER DISKGROUP fra2 MOUNT RESTRICTED; SQL> ALTER DISKGROUP fra2 RENAME DISK 'FRA1_0001' TO 'FRA2_0001', 'FRA1_0002' TO 'FRA2_0002';
For NORMAL
, HIGH
, and FLEX
redundancy disk groups, you can associate a site name using ALTER
DISKGROUP
RENAME
DISK
with the SITE
clause. For example:
SQL> ALTER DISKGROUP data1 RENAME DISK 'DATA1_0001' SITE SITE1;
For information about data sites, extended disk groups, and preferred read for disks, refer to About Oracle ASM Extended Disk Groups and PREFERRED_READ.ENABLED. For information about the ASMCMD stamp
command, refer to stamp.
For an EXTERNAL
redundancy disk group, you can use ALTER
DISKGROUP
RENAME
DISK
with the FAILGROUP
clause to specify a failure group for a disk. For example:
SQL> ALTER DISKGROUP external1 RENAME DISK 'EXTERNAL1_0001' FAILGROUP FG_EXT1_0001;
The SITE
and FAILGROUP
clauses cannot be used together in the same SQL ALTER
DISKGROUP
RENAME
statement.
The ALTER
DISKGROUP
diskgroupname
RENAME
DISKS
ALL
statement can be run after the renamedg
utility to change the names of the disks in the renamed disk group. For information about renamedg
, refer to Renaming Disks Groups.
When you run the ALTER
DISKGROUP
diskgroupname
RENAME
DISKS
ALL
statement, any disk name that is not in the format diskgroupname
_
number
is renamed to that format. Disk names that are already in the diskgroupname
_
number
format are not changed.
Note:
If a disk is labeled by any subsystem; such as ASMLIB, ASMFD, EXADATA, or ASMTOOL; then that label becomes the disk name by design. The ALTER
DISKGROUP
RENAME
DISKS
SQL statement on these subsystems has no effect and the disk is not renamed.
Dropping Disks from Disk Groups
You can drop disks from a disk group with the DROP
DISK
clause of the ALTER
DISKGROUP
statement.
You can also drop all of the disks in specified failure groups using the DROP
DISKS
IN
FAILGROUP
clause.
When a disk is dropped, the disk group is rebalanced by moving all of the file extents from the dropped disk to other disks in the disk group. A drop disk operation might fail if not enough space is available on the other disks. The best approach is to perform both the add and drop operation with the same ALTER
DISKGROUP
statement. This has the benefit of rebalancing data extents only one time and ensuring that there is enough space for the rebalance operation to succeed.
Caution:
The ALTER
DISKGROUP
...
DROP
DISK
SQL statement returns to SQL prompt before the drop and rebalance 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 time remaining for the drop/rebalance operation to complete.
If you specify the FORCE
clause for the drop operation, the disk is dropped even if Oracle ASM cannot read or write to the disk. You cannot use the FORCE
flag when dropping a disk from an external redundancy disk group.
Caution:
A DROP
FORCE
operation leaves data at reduced redundancy until the subsequent rebalance operation completes. This increases your exposure to data loss if there is a subsequent disk failure during rebalancing. Use DROP
FORCE
with caution.
The statements in Example 4-6 demonstrate how to drop disks from the disk group data1
. The first example drops diska5
from disk group data1
. The second example drops diska5
from disk group data1
, and also illustrates how multiple actions are possible with one ALTER DISKGROUP
statement.
Example 4-6 Dropping disks from disk groups
ALTER DISKGROUP data1 DROP DISK diska5; ALTER DISKGROUP data1 DROP DISK diska5 ADD FAILGROUP failgrp1 DISK '/devices/diska9' NAME diska9;
See Also:
-
Managing Disk Groups with ASMCA for information about dropping disks from a disk group with ASMCA
-
Using the ALTER DISKGROUP SQL Statement to Add Disks to a Disk Group for an example of the
ALTER
DISKGROUP
statement -
Oracle Database Reference for information about the
V$ASM_OPERATION
view -
Oracle Database SQL Language Reference for information about the
ALTER
DISKGROUP
SQL statement
Resizing Disks in Disk Groups
The RESIZE
clause of ALTER
DISKGROUP
enables you to resize disks in a disk group.
When resizing disks in a disk group, all the disks must be of equal size.
If you do not specify a new size in the SIZE
clause, then Oracle ASM uses the size of the disks as returned by the operating system. The new size is written to the Oracle ASM disk header and if the size is increasing, then the new space is immediately available for allocation. If the size is decreasing, rebalancing must relocate file extents beyond the new size limit to available space below the limit. If the rebalance operation can successfully relocate all extents, then the new size is made permanent, otherwise the rebalance fails.
The following example resizes all of the disks in the disk group data1
. If the new size is greater than the capacity of a disk, then the statement fails.
Example 4-7 Resizing disks in disk groups
ALTER DISKGROUP data1 RESIZE ALL SIZE 100G;
Undropping Disks in Disk Groups
The UNDROP DISKS
clause of the ALTER
DISKGROUP
statement enables you to cancel all pending drops of disks within disk groups.
If a drop disk operation has completed, then this statement cannot be used to restore it. This statement cannot be used to restore disks that are being dropped as the result of a DROP
DISKGROUP
statement, or for disks that are being dropped using the FORCE
clause.
The following example cancels the dropping of disks from disk group data1
:
Example 4-8 Undropping disks in disk groups
ALTER DISKGROUP data1 UNDROP DISKS;
Note:
-
Oracle Database SQL Language Reference for information about the
DROP
DISKGROUP
SQL statement -
Oracle Database SQL Language Reference for information about the
ALTER
DISKGROUP
SQL statement
Manually Rebalancing Disk Groups
You can manually rebalance the files in a disk group using the REBALANCE
clause of the ALTER
DISKGROUP
statement.
Manual rebalancing would normally not be required because Oracle ASM automatically rebalances disk groups when their configuration changes, including changes to file groups. However, you might want to do a manual rebalance operation to control the speed of what would otherwise be an automatic rebalance operation.
The POWER
clause of the ALTER
DISKGROUP
REBALANCE
statement specifies the degree of parallelism, and the speed of the rebalance operation. A higher value increases the speed of the rebalance operation. It can be set to a minimum value of 0
which stops a rebalancing operation until the statement is either implicitly or explicitly rerun.
The default rebalance power is set by the ASM_POWER_LIMIT
initialization parameter. The range of values for the POWER
clause is the same for the ASM_POWER_LIMIT
initialization parameter.
The power level of an ongoing rebalance operation can be changed by entering the rebalance statement using the MODIFY
POWER
clause. For example, the following SQL statement modifies the power setting to 10
of an ongoing rebalance.
ALTER DISKGROUP data2 REBALANCE MODIFY POWER 10;
The the following SQL statement modifies the power setting to the default value.
ALTER DISKGROUP data2 REBALANCE MODIFY POWER;
When you rebalance a disk group, you have the option choosing the following phase options using the WITH
or WITHOUT
keywords, except where noted:
-
RESTORE
The
RESTORE
phase includesRESYNC
,RESILVER
, andREBUILD
operations. TheRESTORE
phase is always run by default and cannot be excluded.-
RESYNC
This operation synchronizes the stale extents on the disks that are being brought online.
-
RESILVER
This operation is specific only to Exadata systems. During this phase, data is copied from one mirror to the mirror with stale data.
-
REBUILD
This operation restores the redundancy of forcing disks only. Forcing disks are those disks that have been dropped with the force option.
-
-
BALANCE
This phase restores redundancy of all the disks in the disk group, including file groups, and also balances extents on Oracle ASM disks.
-
PREPARE
This phase completes the work corresponding to the prepare SQL operation. This phase is enabled only for
FLEX
orEXTENDED
redundancy disk groups.COMPATIBLE.ASM
must be set to12.2
or higher. -
COMPACT
This phase defragments and compacts extents across Oracle ASM disks.
The rebalance operation executes the phases in the optimal order. If none of the phases are specified with the ALTER DISKGROUP...REBALANCE
SQL statement, then the behavior remains the same as the rebalance operation previous to the Oracle ASM 12.2 release during which all rebalance phases are run.
The following examples show the use of the phase options with ALTER DISKGROUP...REBALANCE
:
ALTER DISKGROUP data2 REBALANCE WITH BALANCE COMPACT; ALTER DISKGROUP data3 REBALANCE WITHOUT BALANCE;
The ALTER DISKGROUP...REBALANCE
command returns immediately by default so that you can run other commands while the rebalance operation takes place asynchronously in the background. You can query the V$ASM_OPERATION
view for the status of the rebalance operation. When not all rebalance phases are run, the V$ASM_OPERATION
view displays an ORA-59000
error at the end of the rebalance.
To cause the ALTER DISKGROUP...REBALANCE
command to wait until the rebalance operation is complete before returning, add the WAIT
keyword to the REBALANCE
clause. The wait functionality is especially useful in scripts. The command also accepts a NOWAIT
keyword, which invokes the default behavior of conducting the rebalance operation asynchronously. You can interrupt a rebalance running in wait mode by typing CTRL+C
on most platforms. This causes the command to return immediately with the message ORA-01013: user requested cancel of current operation
, and then continues the rebalance operation asynchronously.
Additional rules for the rebalance operation include the following:
-
An ongoing rebalance command is restarted if the storage configuration changes either when you alter the configuration, or if the configuration changes due to a failure or an outage. Furthermore, if the new rebalance fails because of a user error, then a manual rebalance may be required.
-
The
ALTER DISKGROUP...REBALANCE
statement runs on a single node even if you are using Oracle Real Application Clusters (Oracle RAC). -
Oracle ASM can perform one disk group rebalance at a time on a given instance. If you have initiated multiple rebalances on different disk groups on a single node, then Oracle processes these operations in parallel on additional nodes if available; otherwise the rebalances are performed serially on the single node. You can explicitly initiate rebalances on different disk groups on different nodes in parallel.
-
Rebalancing continues across a failure of the Oracle ASM instance performing the rebalance.
-
The
REBALANCE
clause (with its associatedPOWER
andWAIT/NOWAIT
keywords) can also be used inALTER DISKGROUP
commands that add, drop, or resize disks.Note:
Oracle restarts the processing of an ongoing rebalance operation if the storage configuration changes. If the next rebalance operation fails because of a user error, then a manual rebalance may be required.
The following example manually rebalances the disk group data2
. The command does not return until the rebalance operation is complete. All supported phases of the rebalance operation are executed. Note that specifying RESTORE
is not necessary as that phase is always run during a rebalance.
Example 4-9 Manually rebalancing a disk group
ALTER DISKGROUP data2 REBALANCE RESTORE POWER 5 WAIT;
See Also:
-
ASM_POWER_LIMIT for information about the
ASM_POWER_LIMIT
initialization parameter -
Tuning Rebalance Operations for information about rebalancing operations
-
Oracle Database SQL Language Reference for information about the
ALTER
DISKGROUP
SQL statement
Tuning Rebalance Operations
If the POWER
clause is not specified in an ALTER
DISKGROUP
statement, or when rebalance is implicitly run by adding or dropping a disk, then the rebalance power defaults to the value of the ASM_POWER_LIMIT
initialization parameter. You can adjust the value of this parameter dynamically. The range of values for the POWER
clause is the same for the ASM_POWER_LIMIT
initialization parameter.
The higher the power limit, the more quickly a rebalance operation can complete. Rebalancing takes longer with lower power values, but consumes fewer processing and I/O resources which are shared by other applications, such as the database.
Oracle ASM tries to keep a rebalance I/O for each unit of power. Each I/O requires PGA memory for the extent involved in the relocation.
The default value of 1
minimizes disruption to other applications. The appropriate value is dependent on your hardware configuration, performance requirements, and availability requirements. Oracle ASM always adjusts the power to fit available memory.
When the COMPATIBLE.ASM
disk group is set to 11.2.0.2
or higher, the rebalance operation may be run as one process using asynchronous I/O. You can check the Oracle ASM alert log for details on the rebalance process.
If a rebalance is in progress because a disk is manually or automatically dropped, then increasing the power of the rebalance shortens the time frame during which redundant copies of that data on the dropped disk are reconstructed on other disks.
You can also affect rebalance behavior with the CONTENT.CHECK
and THIN_PROVISIONED
disk group attributes.
The EXPLAIN
WORK
SQL statement determines the amount of work for a rebalance operation and the resulting calculations are displayed in the V$ASM_ESTIMATE
view.
For example:
EXPLAIN WORK FOR ALTER DISKGROUP data DROP DISK data_0000; Explained. SELECT est_work FROM V$ASM_ESTIMATE; EST_WORK -------- 4211 EXPLAIN WORK SET STATEMENT_ID='online' FOR ALTER DISKGROUP data ONLINE disk data_000; Explained. SELECT est_work FROM V$ASM_ESTIMATE WHERE STATEMENT_ID='online'; EST_WORK -------- 421
The V$ASM_ESTIMATE
view provides information for adjusting ASM_POWER_LIMIT
and the resulting power of rebalance operations. The EST_WORK
column provides an estimate of the number of allocation units that have to be moved by the rebalance operation to complete.
The PASS
column of V$ASM_OPERATION
is updated for resync and rebalance operations. The contents of the column can be RESYNC
, REBALANCE
, or COMPACT
. For example, the following SQL query shows values in the PASS
column during a rebalance operation.
SQL> SELECT GROUP_NUMBER, PASS, STATE FROM V$ASM_OPERATION; GROUP_NUMBER PASS STAT ------------ --------- ---- 2 RESYNC WAIT 2 REBALANCE WAIT 2 COMPACT WAIT
See Also:
-
ASM_POWER_LIMIT for information about the
ASM_POWER_LIMIT
initialization parameter -
Summary of Disk Group Attributes for information about disk group attributes
-
Manually Rebalancing Disk Groupsfor more information about rebalancing disk groups
Scrubbing Disk Groups
Oracle ASM disk scrubbing improves availability and reliability by searching for data that may be less likely to be read. Disk scrubbing checks logical data corruptions and repairs them automatically in normal and high redundancy disks groups. The scrubbing process repairs logical corruptions using the mirror disks. Disk scrubbing can be combined with disk group rebalancing to reduce I/O resources. The disk scrubbing process has minimal impact to the regular I/O in production systems.
You can perform scrubbing on a disk group, a specified disk, or a specified file of a disk group with the ALTER
DISKGROUP
SQL statement. For example, the following SQL statements show various options used when running the ALTER
DISKGROUP
disk_group
SCRUB
SQL statement.
SQL> ALTER DISKGROUP data SCRUB POWER LOW; SQL> ALTER DISKGROUP data SCRUB FILE '+DATA/ORCL/DATAFILE/example.266.806582193' REPAIR POWER HIGH FORCE; SQL> ALTER DISKGROUP data SCRUB DISK DATA_0005 REPAIR POWER HIGH FORCE;
When using ALTER
DISKGROUP
with the SCRUB
option, the following items apply:
-
The optional
REPAIR
option automatically repairs disk corruptions. If theREPAIR
option is not specified, then theSCRUB
option only checks and reports logical corruptions of the specified target. -
The optional
POWER
value can be set toAUTO
,LOW
,HIGH
, orMAX
. If thePOWER
option is not specified, the power value defaults toAUTO
and the power adjusts to the optimum level for the system. -
If the optional
WAIT
option is specified, the command returns after the scrubbing operation has completed. If theWAIT
option is not specified, the scrubbing operation is added into the scrubbing queue and the command returns immediately. -
If the optional
FORCE
option is specified, the command is processed even if the system I/O load is high or scrubbing has been disabled internally at the system level.
The scrubbing process is visible in the fields of the V$ASM_OPERATION
view while the scrubbing process is running.