Automatic Storage Management ( ASM )
Automatic
Storage Management (ASM)
Oracle Database
10g Release 1, introduced Automatic Storage Management (ASM),
a new framework for managing Oracle database files,
to bypass the OS overhead,
to simplify Oracle data management,
to enforce the SAME (Stripe And Mirror Everywhere,
RAID10), and
to provide a platform for file sharing in RAC and Grid computing.
Automatic Storage Management (ASM) is a new type of file
system. ASM provided a foundation for highly efficient storage management with
kernelized asynchronous I/O, direct I/O, redundancy, striping, and an
easy way to manage storage. ASM is recommended file system for RAC and single instance ASM for
storing database files. This provides direct I/O to the file and performance is
comparable with that provided by raw devices. Oracle creates a separate instance
for this purpose.
ASM includes volume management functionality similar to that of a
generic logical volume manager. Automatic StorageManagement (ASM) will
take physical disk partitions and manages their contents in a way that
efficiently supports the files needed to create an Oracle database.
Automatic Storage Management (ASM) simplifies administration
of Oracle related files by allowing the administrator to reference diskgroups
rather than hundreds of individual disks and files, which are managed
by ASM. The ASM functionality is an extension of the Oracle Managed Files (OMF)
functionality that also includes striping and mirroring to provide balanced and
secure storage. The ASM functionality can be used in combination with existing
raw and cooked file systems, along with OMF and manually managed files.
Before ASM, there were only two choices: file system storage and
raw disk storage. File system storage is flexible, allowing the DBA to see the individual files
and to move them, copy them, and back them up easily, but it also incurs
overhead. Raw disk storage has no file directories on it, and Oracle manages
its blocks directly, which makes it more efficient. Raw disk storage is such a
manageability nightmare that few DBAs use it.
ASM is the middle ground. It's raw disk storage managed by Oracle,
and it is very efficient. Oracle uses a scaled down Oracle instance to simulate
a file structure on it where none exists, by recording all the metadata. The
metadata enables the Recovery Manager
(RMAN) to backup and restore Oracle files easily within it.
Setting up storage takes a significant amount of time during most
database installations. Zeroing on a specific disk configuration from among the
multiple possibilities requires careful planning and analysis, and most
important, intimate knowledge of storage technology, volume managers, and file
systems. The design tasks at this stage can be loosely described as follows:
1.
Confirm that storage is recognized at the OS level and determine
the level of redundancy protection that might already be provided (hardware
RAID, called external redundancy in ASM).
2.
Assemble and build logical volume groups and determine if
striping or mirroring is also necessary.
3.
Build a file system on the logical volumes created by the logical
volume manager.
4.
Set the ownership and privileges so that the Oracle process can
open, read, and write to the devices.
5.
Create a database on that file system while taking care to create
special files such as redo logs, temporary
tablespaces, and undo tablespaces in
non-RAID locations, if possible.
All above tasks, striping, mirroring, logical file system building, are done to serve Oracle database. Oracle database offers some techniques of its own to simplify or enhance the process. Lets DBAs execute many of the above tasks completely within the Oracle framework. Using ASM you can transform a bunch of disks to a highly scalable and performance file system/volume manager using nothing more than what comes with Oracle database software at no extra cost and you don't need to be an expert in disk, volume managers, or file system management.
You can store the following file types in ASM diskgroups:
o
Datafiles
o
Control files
o
Online redo logs
o
Archive logs
o
Flashback logs
o
SPFILEs
o
RMAN backups
o
Temporary datafiles
o
Datafile copies
o
Disaster recovery configurations
o
Change tracking bitmaps
o
Datapump dumpsets
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In summary, ASM provides the following functionality/features:
·
Manages groups of disks, called diskgroups. Must be careful while
choosing disks for a diskgroup.
·
Manages disk redundancy within a diskgroup.
·
Provides near-optimal I/O balancing without any manual tuning.
·
Enables management of database objects without specifying mount
points and filenames.
·
Supports large files.
·
Replacement for CFS (Cluster File System).
·
Also useful for Non-RAC databases.
·
A new instance type - ASM is introduced in 10g.
·
ASM instance has no data dictionary.
·
A Disk can be a partial, full or a LUN from the RG.
·
I/O is spread evenly across all disks of a diskgroup.
·
Disks can be dynamically added to any diskgroup.
·
When combined with OMF increases manageability.
·
ASM cannot maintain empty directories “delete input” has issues,
create a dummy directory.
·
Use of ASM diskgroup is very simple create tablespace.
·
Enterprise Manager can also be used for administering diskgroups
·
Only RMAN can be used with ASM.
·
Introduces three additional Oracle
background processes – RBAL, ARBx and ASMB.
o
ASMB - This ASMB process is used to provide information to and
from cluster synchronization services used by ASM to manage the disk resources.
It's also used to update statistics and
provide a heart beat mechanism.
o
Re-Balance, RBAL - RBAL is the ASM related process that performs
rebalancing of disk resources controlled by ASM.
o
Actual Rebalance, ARBx - ARBx is configured by ASM_POWER_LIMIT.
·
ASM instance has it own set of v$views and init.ora parameters.
The advantages of ASM are
§ Disk
Addition - Adding a disk is very easy. No downtime is required and file extents
are redistributed automatically.
§ I/O
Distribution - I/O is spread over all the available disks automatically,
without manual intervention, reducing chances of a hot spot.
§ Stripe
Width - Striping can be fine grained as in redolog files (128K for faster
transfer rate) and coarse for datafiles (1MB for transfer of a large number of
blocks at one time).
§ Mirroring
- Software mirroring can be set up easily, if hardware mirroring is not
available.
§ Buffering
- The ASM file system is not buffered, making it direct I/O capable by design.
§ Kernelized Asynchronous I/O
- There is no special setup necessary to enable kernelized asynchronous I/O,
without using raw or third-party file systems such as Veritas Quick I/O.
ASM
Instance
The ASM functionality is controlled by an ASM instance. This is a
special instance, not a database where users can create objects, just the
memory structures and as such is very small and lightweight.
With ASM, you don't have to create anything on the OS side; the
feature will group a set of physical disks to a logical entity known as a
diskgroup. A diskgroup is analogous to a striped and optionally mirrored, file
system, with important differences: it's not a general-purpose file system for
storing user files and it's not buffered. Diskgroup offers the advantage of
direct access to this space as a raw device, yet provides the convenience and
flexibility of a file system. All the metadata about the disks are stored in
the diskgroups themselves, making them as self-describing as possible.
This special ASM instance is similar to other file systems in that
it must be running for ASM to work and can't be modified by the user. One ASM
instance can serve number of Oracle databases. ASM instance and database
instances have to be present on same server. Otherwise it will not work.
Logical volume managers typically use a function, such as hashing,
to map the logical address of the blocks to the physical blocks. This
computation uses CPU cycles. When a new disk is added, this typical striping
function requires each bit of the entire data set to be relocated. In contrast,
ASM uses this special instance to address the mapping of the file extents to
the physical disk blocks. This design, in addition to being fast in locating
the file extents, helps while adding or removing disks because the locations of
file extents need not be coordinated.
You should start the instance up when the server is booted i.e. it
should be started before the database instances, and it should be one of the
last things stopped when the server is shutdown. From 11.2.0,
we can use ASMCMD to
start and stop the ASM instances.
The initialization parameters that are specific to an ASM instance
are:
·
INSTANCE_TYPE - Set to ASM. The default is RDBMS.
·
ASM_DISKGROUPS - The list of diskgroups that should be mounted by
an ASM instance during instance startup, or by the ALTER DISKGROUP ALL MOUNT
statement. ASM configuration changes are automatically reflected in this
parameter.
·
ASM_DISKSTRING - Specifies a value that can be used to limit the
disks considered for discovery. The default value is NULL allowing all suitable
disks to be considered. Altering the default value may improve the speed of
diskgroup mount time and the speed of adding a disk to a diskgroup. Changing
the parameter to a value which prevents the discovery of already mounted disks
results in an error.
·
ASM_POWER_LIMIT -The maximum power for a rebalancing operation on
an ASM instance. The valid values range from 1 (default) to 11. The higher the
limit the more resources are allocated resulting in faster rebalancing
operations. This value is also used as the default when the POWER clause is
omitted from a rebalance operation. A value of 0 disables rebalancing.
·
ASM_PREFERRED_READ_FAILURE_GROUPS - This initialization parameter
value (default is NULL) is a comma-delimited list of strings that specifies the
failure groups that should be preferentially read by the given instance. This
parameter is generally used only for clustered ASM instances and its value can
be different on different nodes. This is from Oracle 11g.
·
DB_UNIQUE_NAME - Specifies a globally unique name for the
database. This defaults to +ASM but must be altered if you intend to run
multiple ASM instances.
To create an ASM instance first create pfile, init+ASM.ora, in the
/tmp directory, containing the following parameter.
INSTANCE_TYPE = ASM
Next, connect to the ideal instance.
$ export ORACLE_SID=+ASM
SQL> sqlplus "/as sysdba"
Create a spfile using the contents of the init+ASM.ora file.
SQL> CREATE SPFILE FROM PFILE='/tmp/init+ASM.ora';
SQL> startup nomount
ASM instance started
Total System Global Area 130023424 bytes
Fixed Size 2028368 bytes
Variable Size 102829232 bytes
ASM Cache 25165824 bytes
The ASM instance is now ready to use for creating and mounting
diskgroups.
Once an ASM instance is present, diskgroups can be used for the
following parameters in database instances (INSTANCE_TYPE=RDBMS) to allow ASM
file creation:
·
CONTROL_FILES
·
DB_CREATE_FILE_DEST
·
DB_CREATE_ONLINE_LOG_DEST_n
·
DB_RECOVERY_FILE_DEST
·
LOG_ARCHIVE_DEST_n
·
LOG_ARCHIVE_DEST
·
STANDBY_ARCHIVE_DEST
Startup of ASM Instances
ASM instances are started and
stopped in a similar way to normal database instances.
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The options for the STARTUP command are:
·
NOMOUNT - Starts the ASM instance without mounting any diskgroups.
·
MOUNT - Starts the ASM instance and mounts the diskgroups
specified by the ASM_DISKGROUPS parameter.
·
OPEN - ASM instance does not have open stage.
·
FORCE - Performs a SHUTDOWN ABORT before restarting the ASM
instance.
ASMCMD equivalent
for this command is startup (11g R2 command).
Shutdown of ASM Instances
The options for the SHUTDOWN command are:
Shutdown of ASM Instances
The options for the SHUTDOWN command are:
·
NORMAL - The ASM instance waits for all connected ASM instances
and SQL sessions to exit then shuts down.
·
IMMEDIATE - The ASM instance waits for any SQL transactions to
complete then shuts down. It doesn't wait for sessions to exit.
·
TRANSACTIONAL - Same as IMMEDIATE.
·
ABORT - The ASM instance shuts down instantly.
ASMCMD equivalent
for this command is shutdown (11g
R2 command).
ASM Diskgroups
ASM Diskgroups
The main components of ASM are diskgroups, each of which comprise
of several physical disks that are controlled as a single unit. The physical
disks are known as ASM disks, while the files that reside on the disks are
known as ASM files. The locations and names for the files are controlled by
ASM, but user-friendly aliases and directory structures can be defined for ease
of reference.
Diskgroup is a terminology used for logical structure which holds
the database files. Each diskgroup consists of disks/raw devices where the
files are actually stored. Any ASM file (and it's redundant copy) is completely
contained within a single diskgroup. A diskgroup might contain files belonging
to several databases and a single database can use files from multiple
diskgroups.
In the initial release of Oracle 10g,
ASM diskgroups were a black box. We had to manipulate ASM diskgroups with SQL
statements while logged in to the special ASM instance that manages the
diskgroups.
In Oracle 10g
Release 2, Oracle introduced a new command line tool called ASMCMD that
lets you look inside ASM volumes (which are called diskgroups). Now you can do
many tasks from the command line.
While creating a diskgroup, we have to specify an ASM diskgroup
type based on one of the following three redundancy levels:
·
Normal redundancy - for 2-way mirroring, requiring two failure
groups, when ASM allocates an extent for a normal redundancy file, ASM
allocates a primary copy and a secondary copy. ASM chooses the disk on which to
store the secondary copy in a different failure group other than the primary
copy.
·
High redundancy - for 3-way mirroring, requiring three failure
groups, in this case the extent is mirrored across 3 disks.
·
External redundancy - to not use ASM mirroring. This is used if
you are using hardware mirroring or third party redundancy mechanism like RAID,
Storage arrays.
ASM is supposed to stripe the data and also mirror the data (if
using Normal, High redundancy). So this can be used as an alternative for RAID
(Redundant Array of Inexpensive Disks) 0+1 solutions.
No, we cannot modify the redundancy for diskgroup once it has been
created. To alter it we will be required to create a new diskgroup and move the
files to it. This can also be done by restoring full backup on the new
diskgroup.
Failure groups are defined within a diskgroup to support the
required level of redundancy, using normal/high redundancy. They contain the
mirrored ASM extents and must be containing different disks and preferably on
separate disk controller.
In addition failure groups and preferred names for disks can be
defined in CREATE DISKGROUP statement. If the NAME clause is omitted the disks
are given a system generated name like "disk_group_1_0001". The FORCE
option can be used to move a disk from another diskgroup into this one.
Creating
diskgroups
SQL> CREATE DISKGROUP dg_asm_data NORMAL REDUNDANCY
FAILGROUP failure_group_1 DISK
'/devices/diska1' NAME diska1, '/devices/diska2' NAME diska2,
FAILGROUP failure_group_2 DISK
'/devices/diskb1' NAME diskb1, '/devices/diskb2' NAME diskb2;
For two-way mirroring we would expect a diskgroup to contain two
failure groups, so individual files are written to two locations.
SQL> CREATE DISKGROUP dg_asm_fra HIGH REDUNDANCY
FAILGROUP failure_group_1 DISK
'/devices/diska1' NAME diska1, '/devices/diska2' NAME diska2,
FAILGROUP failure_group_2 DISK
'/devices/diskb1' NAME diskb1, '/devices/diskb2' NAME diskb2,
FAILGROUP failure_group_3 DISK
'/devices/diskc1' NAME diskc1, '/devices/diskc2' NAME diskc2;
For three-way mirroring we would expect a diskgroup to contain
three failure groups, so individual files are written to three locations.
SQL> CREATE DISKGROUP dg_grp1 EXTERNAL REDUNDANCY
DISK '/dev/d1','/dev/d2','/dev/d3','/dev/d4' ... ...;
In the above command, database will create a diskgroup named
dg_grp1 with the physical disks named /dev/d1, /dev/d2, and so on. Instead of
giving disks separately, we can also specify disk names in wildcards in the
DISK clause as DISK '/dev/d*'.
We have also specified a clause EXTERNAL REDUNDANCY, which
indicates that the failure of a disk will bring down the diskgroup. This is
usually the case when the redundancy is provided by the hardware, such as mirroring.
If there is no hardware based redundancy, the ASM can be set up to create a
special set of disks called failgroup in the diskgroup to provide that
redundancy.
SQL> CREATE DISKGROUP dskgrp1 NORMAL REDUNDANCY
FAILGROUP failgrp1 DISK '/dev/d1','/dev/d2',
FAILGROUP failgrp2 DISK '/dev/d3','/dev/d4';
Although it may appear as such, d3 and d4 are not mirrors of d1
and d2. Rather, ASM uses all the disks to create a fault-tolerant system. For
example, a file on the diskgroup might be created in d1 with a copy maintained
on d4. A second file may be created on d3 with copy on d2, and so on. That is,
primary copy will be on one failure group and secondary copy will be another
(third copy will be another, for high redundancy).
Failure of a specific disk allows a copy on another disk so that
the operation can continue. For example, you could lose the controller for both
disks d1 and d2 and ASM would mirror copies of the extents across the failure
group to maintain data integrity.
SQL> CREATE DISKGROUP dg1 DISK '/dev/raw/*'
ATTRIBUTE 'compatible.rdbms' = '11.1', 'compatible.asm' = '11.1';
(11g R1 command)
SQL> CREATE DISKGROUP dg2 EXTERNAL REDUNDANCY
DISK '/dev/sde1' ATRRIBUTE 'au_size' = '32M'; (11g R1 command)
SQL> CREATE DISKGROUP archdg NORMAL REDUNDANCY
FAILGROUP fg1 DISK
'/devices/diska1','/devices/diska2','/devices/diska3','/devices/diska4'
FAILGROUP fg2 DISK
'/devices/diskb1','/devices/diskb2','/devices/diskb3','/devices/diskb4'
ATTRIBUTE 'au_size'='4M','compatible.asm'='11.2','compatible.rdbms'='11.2','compatible.advm'='11.2'; (11g R2command)
SQL> CREATE DISKGROUP archdg NORMAL REDUNDANCY
FAILGROUP fg1 DISK
'/devices/diska1','/devices/diska2','/devices/diska3','/devices/diska4'
FAILGROUP fg2 DISK
'/devices/diskb1','/devices/diskb2','/devices/diskb3','/devices/diskb4'
ATTRIBUTE 'au_size'='4M','compatible.asm'='11.2','compatible.rdbms'='11.2','compatible.advm'='11.2'; (11g R2command)
ASMCMD equivalent
for this command is mkdg (11g R2 command).
Listing diskgroups
Listing diskgroups
To find out all the diskgroups:
SQL> SELECT * FROM V$ASM_DISKGROUP;
ASMCMD equivalent
for this command is lsdg.
Dropping
diskgroups
Diskgroups can be deleted using the DROP DISKGROUP statement.
SQL> DROP DISKGROUP disk_group_1 INCLUDING CONTENTS;
SQL> DROP DISKGROUP disk_group_1 FORCE; (11g R1 command)
SQL> DROP DISKGROUP disk_group_1 FORCE INCLUDING CONTENTS; (11gR1 command)
ASMCMD equivalent
for this command is dropdg (11g R2 command).
Altering
diskgroups
Disks can be added or removed from diskgroups using the ALTER
DISKGROUP statement. Remember that the wildcard "*" can be used to
reference disks so long as the resulting string does not match a disk already
used by an existing diskgroup.
Adding disks
We may have to add additional disks into the diskgroup to
accommodate growing demand.
SQL> ALTER DISKGROUP dskgrp1 ADD DISK '/dev/d5';
SQL> ALTER DISKGROUP dg1 ADD DISK '/devices/disk*3',
'/devices/disk*4';
ASMCMD equivalent
for this command is chdg (11g R2 command).
Listing disks
Listing disks
The following command shows all the disks managed by the ASM
instance for all the client databases.
SQL> SELECT * FROM V$ASM_DISK;
ASMCMD equivalent
for this command is lsdsk (11g R1 command).
Listing
client databases
The following command shows all the database instances connected
to the ASM instance.
SQL> SELECT * FROM V$ASM_CLIENT;
ASMCMD equivalent
for this command is lsct.
Dropping disks
We can remove a disk from diskgroup.
SQL> ALTER DISKGROUP dg4 DROP DISK diska4;
ASMCMD equivalent for this command is chdg (11g R2 command).
ASMCMD equivalent for this command is chdg (11g R2 command).
Resizing disks
Disks can be resized using the RESIZE clause of the ALTER
DISKGROUP statement. The statement can be used to resize individual disks, all
disks in a failure group or all disks in the diskgroup. If the SIZE clause is
omitted the disks are resized to the size of the disk returned by the OS.
SQL> ALTER DISKGROUP dg_data_1 RESIZE DISK diska1 SIZE 150G;
Resizing all disks in a failure group
SQL> ALTER DISKGROUP dg_data_1 RESIZE DISKS IN FAILGROUP fg_1
SIZE 50G;
Resizing all disks in a diskgroup
SQL> ALTER DISKGROUP dg_data_1 RESIZE ALL SIZE 100G;
Undropping disks
The UNDROP DISKS clause of the ALTER DISKGROUP statement allows
pending disk drops to be undone. It will not revert drops that have completed,
or disk drops associated with the dropping of a diskgroup.
SQL> ALTER DISKGROUP disk_group_1 UNDROP DISKS;
Online disks
SQL> ALTER DISKGROUP data ONLINE DISK 'disk_0000', 'disk_0001';
SQL> ALTER DISKGROUP data ONLINE DISKS IN FAILGROUP 'fg_99';
SQL> ALTER DISKGROUP data ONLINE ALL;
ASMCMD equivalent for this command is online (11gR2 command).
Offline disks
ASMCMD equivalent for this command is online (11gR2 command).
Offline disks
SQL> ALTER DISKGROUP data OFFLINE DISK 'disk_0000',
'disk_0001';
SQL> ALTER DISKGROUP data OFFLINE DISKS IN FAILGROUP 'fg_99';
SQL> ALTER DISKGROUP data OFFLINE DISK d1_0001 DROP AFTER 30m;
ASMCMD equivalent
for this command is offline (11gR2 command).
Mounting diskgroups
Diskgroups are mounted at ASM instance startup and unmounted at
ASM instance shutdown. Manual mounting and dismounting can be accomplished
using the ALTER DISKGROUP statement as below.
SQL> ALTER DISKGROUP ALL MOUNT;
SQL> ALTER DISKGROUP dg_data2 MOUNT;
SQL> ALTER DISKGROUP dg_data2 MOUNT RESTRICTED; (11gR1 command)
ASMCMD equivalent
for this command is mount (11gR2 command).
Dismounting diskgroups
Dismounting diskgroups
SQL> ALTER DISKGROUP ALL DISMOUNT;
SQL> ALTER DISKGROUP dg_fra DISMOUNT;
ASMCMD equivalent
for this command is umount (11gR2 command).
Changing
attributes
SQL> ALTER DISKGROUP data3 SET ATTRIBUTE 'compatible.rdbms' =
'11.1'; (11gR1 command)
SQL> ALTER DISKGROUP data3 SET ATTRIBUTE 'compatible.asm' =
'11.2';
(11gR1 command)
SQL> ALTER DISKGROUP data3 SET ATTRIBUTE 'disk_repair_time' =
'4.5h'; (11gR1 command)
ASMCMD equivalent for this command is setattr (11gR2 command).
Listing attributes
SQL> SELECT * FROM V$ASM_ATTRIBUTE;
ASMCMD equivalent for this command is lsattr (11gR2 command).
ASMCMD equivalent for this command is setattr (11gR2 command).
Listing attributes
SQL> SELECT * FROM V$ASM_ATTRIBUTE;
ASMCMD equivalent for this command is lsattr (11gR2 command).
Rebalancing
Diskgroups can be rebalanced manually using the REBALANCE clause
of the ALTER DISKGROUP statement. If the POWER clause is omitted the
ASM_POWER_LIMIT parameter value is used. Rebalancing is only needed when the
speed of the automatic rebalancing is not appropriate.
SQL> ALTER DISKGROUP disk_group_1 REBALANCE POWER 6;
ASMCMD equivalent for this command is rebal (11gR2 command).
IO statistics of a diskgroup
SQL> SELECT * FROM V$ASM_DISK_IOSTAT;
ASMCMD equivalent for this command is rebal (11gR2 command).
IO statistics of a diskgroup
SQL> SELECT * FROM V$ASM_DISK_IOSTAT;
ASMCMD equivalent
for this command is iostat (11gR2 command).
Until 11.1.0, all the above commands can not be performed with ASMCMD.
From 11.2.0,
we can.
Directories
As in other file systems, an ASM directory is a container for
files, and an ASM directory can be part of a tree structure of other
directories. The fully qualified filename represents a hierarchy of directories
in which the plus sign (+) represent the root directory. In each diskgroup, ASM
automatically creates a directory hierarchy that corresponds to the structure
of the fully qualified filenames in the diskgroup. The directories in this
hierarchy are known as system-generated directories.
An absolute path refers to the full path of a file or directory.
An absolute path begins with a plus sign (+) followed by a diskgroup name,
followed by subsequent directories in the directory tree. The absolute path
includes directories until the file or directory is reached. A fully qualified
filename is an example of an absolute path to a file. A relative path includes
only the part of the filename or directory name that is not part of the current
directory. That is, the path to the file or directory is relative to the
current directory.
A directory hierarchy can be defined using the ALTER DISKGROUP
statement to support ASM file aliasing.
Creating
a directory
SQL> ALTER DISKGROUP dg_1 ADD DIRECTORY '+dg_1/my_dir';
ASMCMD equivalent
for this command is mkdir.
Renaming
a directory
SQL> ALTER DISKGROUP dg_1 RENAME DIRECTORY '+dg_1/my_dir' TO
'+dg_1/my_dir_2';
Deleting
a directory
SQL> ALTER DISKGROUP dg_1 DROP DIRECTORY '+dg_1/my_dir_2'
FORCE;
ASMCMD equivalent
for this command is rm.
Files
There are several ways to reference ASM files. Some forms are used
during creation and some for referencing ASM files. Every file created in ASM
gets a system-generated filename, known as fully qualified filename, this is
same as complete path name in a local file system.
The forms of the ASM filenames are:
Filename Type
|
Format
|
Fully
Qualified ASM Filename
|
+dgroup/dbname/file_type/
file_type_tag.file.incarnation
|
Numeric
ASM Filename
|
+dgroup.file.incarnation
|
Alias
ASM Filenames
|
+dgroup/directory/filename
|
Alias
ASM Filename with Template
|
+dgroup(template)/alias
|
Incomplete
ASM Filename
|
+dgroup
|
Incomplete
ASM Filename with Template
|
+dgroup(template)
|
ASM generates filenames according to the following scheme:
+diskGroupName/databaseName/fileType/fileTypeTag.fileNumber.incarnation
e.g: +dgroup2/crm/CONTROLFILE/Current.256.541956473
+dg_fra/hrms/DATAFILE/users.309.621906475
ASM does not place system-generated files into user-created
directories; it places them only in system-generated directories. We can add
aliases or other directories to a user-created directory.
Dropping Files
Files are not deleted automatically if they are created using aliases, as they are not Oracle Managed Files (OMF), or if a recovery is done to a point-in-time before the file was created. For these circumstances it is necessary to manually delete the files, as shown below.
Files are not deleted automatically if they are created using aliases, as they are not Oracle Managed Files (OMF), or if a recovery is done to a point-in-time before the file was created. For these circumstances it is necessary to manually delete the files, as shown below.
Dropping file using an alias
SQL> ALTER DISKGROUP dg_2 DROP FILE '+dg_2/my_dir/my_file.dbf';
Dropping file using a numeric form filename
SQL> ALTER DISKGROUP dg_2 DROP FILE '+dg_2.321.123456789';
Dropping file using a fully qualified filename
SQL> ALTER DISKGROUP dg_2 DROP FILE
'+dg_2/mydb/datafile/my_ts.292.265390671';
ASMCMD equivalent
for this command is rm.
Aliases
Aliases allow you to reference ASM files using user-friendly
names, rather than the fully qualified ASM filenames.
Creating an alias
Creating an alias, using the fully qualified filename
SQL> ALTER DISKGROUP dg_3 ADD ALIAS '+dg_3/my_dir/users.dbf'
FOR '+dg_3/mydb/datafile/users.392.333222555';
Creating an alias, using the numeric form filename
SQL> ALTER DISKGROUP dg_3 ADD ALIAS '+dg_3/my_dir/my_file.dbf'
FOR '+dg_3.317.111222333';
ASMCMD equivalent
for this command is mkalias.
Renaming an alias
SQL> ALTER DISKGROUP dg_3 RENAME ALIAS
'+dg_3/my_dir/my_file.dbf' TO '+dg_3/my_dir/my_file2.dbf';
Deleting an alias
SQL> ALTER DISKGROUP dg_3 DELETE ALIAS
'+dg_3/my_dir/my_file.dbf';
ASMCMD equivalent
for this command is rmalias.
Attempting to drop a system alias results in an error.
Templates
Templates are named groups of attributes that can be applied to
the files within a diskgroup. The level of redundancy and the granularity of
the striping can be controlled using templates. Default templates are provided
for each file type stored by ASM, but additional templates can be defined as
needed.
Available attributes are:
·
UNPROTECTED - No mirroring or striping regardless of the
redundancy setting.
·
MIRROR - Two-way mirroring for normal redundancy and three-way
mirroring for high redundancy.
·
COARSE - Specifies lower granularity for striping.
·
FINE - Specifies higher granularity for striping.
MIRROR, COARSE, FINE attributes are cannot be set for external
redundancy.
Creating a template
SQL> ALTER DISKGROUP dg_4 ADD TEMPLATE mf_template ATTRIBUTES
(MIRROR FINE);
ASMCMD equivalent
for this command is mktmpl (11gR2 command).
Modifying
a template
SQL> ALTER DISKGROUP dg_4 ALTER TEMPLATE c_template ATTRIBUTES
(COARSE);
ASMCMD equivalent
for this command is chtmpl (11gR2 command).
Listing templates
SQL> SELECT * FROM V$ASM_TEMPLATE;
ASMCMD equivalent for this command is lstmpl (11gR2 command).
Listing templates
SQL> SELECT * FROM V$ASM_TEMPLATE;
ASMCMD equivalent for this command is lstmpl (11gR2 command).
Dropping
a template
SQL> ALTER DISKGROUP dg_4 DROP TEMPLATE u_template;
ASMCMD equivalent
for this command is rmtmpl (11gR2 command).
Checking Metadata
The internal consistency of diskgroup metadata can be checked in a
number of ways using the CHECK clause of the ALTER DISKGROUP statement.
Checking metadata for a specific file
SQL> ALTER DISKGROUP dg_5 CHECK FILE '+dg_5/my_dir/my_file.dbf'
Checking metadata for a specific disk in the diskgroup
SQL> ALTER DISKGROUP dg_5 CHECK DISK diska1;
Checking metadata for a specific failure group in the diskgroup
SQL> ALTER DISKGROUP dg_5 CHECK FAILGROUP failure_group_1;
Checking metadata for all disks in the diskgroup
SQL> ALTER DISKGROUP dg_5 CHECK ALL;
SQL> ALTER DISKGROUP dg_5 CHECK;
SQL> ALTER DISKGROUP dg_5 CHECK NOREPAIR;
SQL> ALTER DISKGROUP dg_5 CHECK REPAIR;
ASMCMD equivalent
for this command is chkdg (11gR2 command).
User Management
From Oracle 11g release 2, we can create ASM users and usergroups and manipulate the permissions and ownership of files.
Creating an ASM usergroup
SQL> ALTER DISKGROUP data_dg ADD USERGROUP 'grp1';
SQL> ALTER DISKGROUP data_dg ADD USERGROUP 'grp2' WITH MEMBER 'oracle1','oracle2';
ASMCMD equivalent for this command is mkgrp (11gR2 command).
Listing ASM usergroups
To find out the list of ASM usergroups.
SQL> SELECT * FROM V$ASM_USERGROUP;
ASMCMD equivalent for this command is lsgrp (11gR2 command).
Dropping an ASM usergroup
SQL> ALTER DISKGROUP data_dg DROP USERGROUP 'grp1';
ASMCMD equivalent for this command is rmgrp (11gR2 command).
Modifying(adding/deleting ASM users to/from) an ASM usergroup
SQL> ALTER DISKGROUP data_dg MODIFY USERGROUP 'grp2' ADD MEMBER 'oracle3';
SQL> ALTER DISKGROUP data_dg MODIFY USERGROUP 'grp2' DROP MEMBER 'oracle3';
ASMCMD equivalent for this command is grpmod (11gR2 command).
Creating an ASM user
SQL> ALTER DISKGROUP data_dg ADD USER 'oracle1';
ASMCMD equivalent for this command is mkusr (11gR2 command).
Listing ASM users
To find out the list of ASM users.
SQL> SELECT * FROM V$ASM_USER;
ASMCMD equivalent for this command is lsusr (11gR2 command).
Listing ASM usergroups to which user belongs
SQL> SELECT * FROM V$ASM_USERGROUP_MEMBER;
ASMCMD equivalent for this command is groups (11gR2 command).
Dropping an ASM user
SQL> ALTER DISKGROUP data_dg DROP USER 'oracle1';
ASMCMD equivalent for this command is rmusr (11gR2 command).
Modifying permissions for a file
SQL> ALTER DISKGROUP data_dg SET PERMISSION OWNER=read write, GROUP=read only, OTHER=none FOR FILE '+data_dg/controlfile.f';
ASMCMD equivalent for this command is chmod (11gR2 command).
Modifying ownership of a file
SQL> ALTER DISKGROUP data_dg SET OWNERSHIP OWNER='oracle1', GROUP='grp1' FOR FILE '+data_dg/controlfile.f';
ASMCMD equivalent for this command is chown (11gR2 command).
Volume Management
From 11g release 2, we can create Oracle ASM Dynamic Volume Manager (Oracle ADVM) volumes in a diskgroups. The volume device associated with the dynamic volume can then be used to host an (Oracle ACFS) file system.
Creating a volume
SQL> ALTER DISKGROUP data_dg ADD VOLUME volume1 SIZE 20G;
ASMCMD equivalent for this command is volcreate (11gR2 command).
Listing volume information
To find out the volumes information.
SQL> SELECT * FROM V$ASM_VOLUME;
ASMCMD equivalent for this command is volinfo (11gR2 command).
Listing volume statistics
To find out the volumes statistics information.
SQL> SELECT * FROM V$ASM_VOLUME_STAT;
ASMCMD equivalent for this command is volstat (11gR2 command).
Dropping a volume
SQL> ALTER DISKGROUP data_dg DROP VOLUME volume1;
ASMCMD equivalent for this command is voldelete (11gR2 command).
Resizing a volume
SQL> ALTER DISKGROUP fra_dg RESIZE VOLUME volume1 SIZE 25G;
ASMCMD equivalent for this command is volresize (11gR2 command).
Disabling a volume
SQL> ALTER DISKGROUP redo_dg DISABLE VOLUME volume1;
SQL> ALTER DISKGROUP ALL DISABLE VOLUME ALL;
ASMCMD equivalent for this command is voldisable (11gR2 command).
Enabling a volume
SQL> ALTER DISKGROUP arch_dg ENABLE VOLUME volume1;
ASMCMD equivalent for this command is volenable (11gR2 command).
Setting a volume
SQL> ALTER DISKGROUP asm_dg_data MODIFY VOLUME volume1 USAGE 'acfs';
ASMCMD equivalent for this command is volset (11gR2 command).
Misc
Listing the current operations
SQL> SELECT * FROM V$ASM_OPERATION;
ASMCMD equivalent for this command is lsop (11gR2 command).
User Management
From Oracle 11g release 2, we can create ASM users and usergroups and manipulate the permissions and ownership of files.
Creating an ASM usergroup
SQL> ALTER DISKGROUP data_dg ADD USERGROUP 'grp1';
SQL> ALTER DISKGROUP data_dg ADD USERGROUP 'grp2' WITH MEMBER 'oracle1','oracle2';
ASMCMD equivalent for this command is mkgrp (11gR2 command).
Listing ASM usergroups
To find out the list of ASM usergroups.
SQL> SELECT * FROM V$ASM_USERGROUP;
ASMCMD equivalent for this command is lsgrp (11gR2 command).
Dropping an ASM usergroup
SQL> ALTER DISKGROUP data_dg DROP USERGROUP 'grp1';
ASMCMD equivalent for this command is rmgrp (11gR2 command).
Modifying(adding/deleting ASM users to/from) an ASM usergroup
SQL> ALTER DISKGROUP data_dg MODIFY USERGROUP 'grp2' ADD MEMBER 'oracle3';
SQL> ALTER DISKGROUP data_dg MODIFY USERGROUP 'grp2' DROP MEMBER 'oracle3';
ASMCMD equivalent for this command is grpmod (11gR2 command).
Creating an ASM user
SQL> ALTER DISKGROUP data_dg ADD USER 'oracle1';
ASMCMD equivalent for this command is mkusr (11gR2 command).
Listing ASM users
To find out the list of ASM users.
SQL> SELECT * FROM V$ASM_USER;
ASMCMD equivalent for this command is lsusr (11gR2 command).
Listing ASM usergroups to which user belongs
SQL> SELECT * FROM V$ASM_USERGROUP_MEMBER;
ASMCMD equivalent for this command is groups (11gR2 command).
Dropping an ASM user
SQL> ALTER DISKGROUP data_dg DROP USER 'oracle1';
ASMCMD equivalent for this command is rmusr (11gR2 command).
Modifying permissions for a file
SQL> ALTER DISKGROUP data_dg SET PERMISSION OWNER=read write, GROUP=read only, OTHER=none FOR FILE '+data_dg/controlfile.f';
ASMCMD equivalent for this command is chmod (11gR2 command).
Modifying ownership of a file
SQL> ALTER DISKGROUP data_dg SET OWNERSHIP OWNER='oracle1', GROUP='grp1' FOR FILE '+data_dg/controlfile.f';
ASMCMD equivalent for this command is chown (11gR2 command).
Volume Management
From 11g release 2, we can create Oracle ASM Dynamic Volume Manager (Oracle ADVM) volumes in a diskgroups. The volume device associated with the dynamic volume can then be used to host an (Oracle ACFS) file system.
Creating a volume
SQL> ALTER DISKGROUP data_dg ADD VOLUME volume1 SIZE 20G;
ASMCMD equivalent for this command is volcreate (11gR2 command).
Listing volume information
To find out the volumes information.
SQL> SELECT * FROM V$ASM_VOLUME;
ASMCMD equivalent for this command is volinfo (11gR2 command).
Listing volume statistics
To find out the volumes statistics information.
SQL> SELECT * FROM V$ASM_VOLUME_STAT;
ASMCMD equivalent for this command is volstat (11gR2 command).
Dropping a volume
SQL> ALTER DISKGROUP data_dg DROP VOLUME volume1;
ASMCMD equivalent for this command is voldelete (11gR2 command).
Resizing a volume
SQL> ALTER DISKGROUP fra_dg RESIZE VOLUME volume1 SIZE 25G;
ASMCMD equivalent for this command is volresize (11gR2 command).
Disabling a volume
SQL> ALTER DISKGROUP redo_dg DISABLE VOLUME volume1;
SQL> ALTER DISKGROUP ALL DISABLE VOLUME ALL;
ASMCMD equivalent for this command is voldisable (11gR2 command).
Enabling a volume
SQL> ALTER DISKGROUP arch_dg ENABLE VOLUME volume1;
ASMCMD equivalent for this command is volenable (11gR2 command).
Setting a volume
SQL> ALTER DISKGROUP asm_dg_data MODIFY VOLUME volume1 USAGE 'acfs';
ASMCMD equivalent for this command is volset (11gR2 command).
Misc
Listing the current operations
SQL> SELECT * FROM V$ASM_OPERATION;
ASMCMD equivalent for this command is lsop (11gR2 command).
Creating Tablespaces
Now create a tablespace in the main database using a datafile in
the ASM-enabled storage.
SQL> CREATE TABLESPACE user_data DATAFILE
'+dskgrp1/user_data_01'
SIZE 1024M;
ASM filenames can be used in place of conventional filenames for
most Oracle file types, including controlfiles, datafiles, logfiles etc. For
example, the following command creates a new tablespace with a datafile in the
disk_group_1 diskgroup.
SQL> CREATE TABLESPACE my_ts DATAFILE '+disk_group_1' SIZE 100M
AUTOEXTEND ON;
Note how the diskgroup is used as a virtual file system. This
approach is useful not only in datafiles, but in other types of Oracle files as
well. For instance, we can create online redo log files as
...
LOGFILE GROUP 1 (
'+dskgrp1/redo/group_1.258.659723485',
'+dskgrp2/redo/group_1.258.659723485'
) SIZE 50M,
...
Archived log destinations can also be set to a diskgroup.
Everything related to Oracle database can be created in an ASM diskgroup.
Backup is another great use of ASM. You can set up a bunch of inexpensive disks
to create the recovery area of
a database, which can be used by RMAN to
create backup datafiles and archived log files.
ASM supports files created by and read by the Oracle database
only; it is not a replacement for a general-purpose file system.
Until Oracle 11g
release1, we cannot store binaries or flat files. We cannot use ASM
for storing the voting disk and OCR. It is due to the fact that Clusterware
starts before ASM instance and it should be able to access these files which
are not possible if you are storing it on ASM. You will have to use raw devices
or OCFS or any other shared storage. But from 11g release 2,
we can store ALL files on ASM.
Can we see the files stored in the ASM instance using standard
Unix commands?
No, you cannot see the files using standard Unix commands like ls.
You need to use utility called asmcmd to do this.Oracle 10g
release2 introduces asmcmd which
makes administration very easy.
$ asmcmd
ASMCMD>
ASMLIB is the support library for the ASM. ASMLIB allows an Oracle
database using ASM more efficient and capable access to diskgroups. The purpose
of ASMLIB, is to provide an alternative interface to identify and access block
devices. ASMLIB API enables storage and OS vendors to supply extended
storage-related features.
Migrating to ASM using RMAN
The following method shows how a database can be migrated to ASM
from a disk based backup:
1) Shutdown the database.
SQL> SHUTDOWN IMMEDIATE
2) Modify the parameter file of the database as follows:
Set DB_CREATE_FILE_DEST and DB_CREATE_ONLINE_LOG_DEST_n parameters
to the relevant ASM diskgroups.
3) Remove CONTROL_FILES parameter from the spfile so the control
files will be moved to the DB_CREATE_* destination and the spfile gets updated
automatically. If you are using a pfile the CONTROL_FILES parameter must be set
to the appropriate ASM files or aliases.
4) Start the database in nomount mode.
RMAN> STARTUP NOMOUNT
5) Restore the controlfile into the new location from the old
location.
RMAN> RESTORE CONTROLFILE FROM 'old_control_file_name';
6) Mount the database.
RMAN> ALTER DATABASE MOUNT;
7) Copy the database into the ASM diskgroup.
RMAN> BACKUP AS COPY DATABASE FORMAT '+disk_group';
8) Switch all datafile to the new ASM location.
RMAN> SWITCH DATABASE TO COPY;
9) Open the database.
RMAN> ALTER DATABASE OPEN;
10) Create new redo logs in ASM and delete the old ones.
ASM New features in Oracle 11g
release1
·
Support for rolling upgrades.
·
We can maintain version compatibilites at diskgroup level.
SQL> alter diskgroup dg-name set attribute 'compatible.rdbms'='11.1';
SQL> alter diskgroup dg-name set attribute 'compatible.asm'='11.1';
SQL> alter diskgroup dg-name set attribute 'compatible.rdbms'='11.1';
SQL> alter diskgroup dg-name set attribute 'compatible.asm'='11.1';
·
ASM drops disks and if they remain offline for more than 3.6
hours. The diskgroups default time limit is altered by changing the
DISK_REPAIR_TIME parameter with a unit of minutes(M/m) or hours(H/h).
SQL> alter diskgroup dg-name set attribute 'disk_repair_time'='4.5h';
SQL> alter diskgroup dg-name set attribute 'disk_repair_time'='4.5h';
·
Automatic bad block detection and repair.
·
Supports variable extent(allocation unit) sizes. The total number
of extents in shared pool will be significantly reduced and improved
performance.
SQL> create diskgroup ... attribute 'au_size' = 'number-of-bytes';
SQL> create diskgroup ... attribute 'au_size' = 'number-of-bytes';
·
New SYSASM role (like SYSDBA, SYSOPER) & OSASM OS group (like
OSDBA, OSOPER) to manage ASM instance only. This will separate storage
administration from database administration.
$ sqlplus "/as sysasm" or $ asmcmd -a sysasm
$ sqlplus "/as sysasm" or $ asmcmd -a sysasm
·
ASM Preferred Mirror Read or Preferred Read Failure Groups -
ASM_PREFERRED_READ_FAILURE_GROUPS parameter is set to the preferred failure
groups for each node.
·
Faster Mirror Resync - Fast mirror resync after temporary
connectivity lost.
·
We can drop a diskgroup forcefully.
SQL> drop diskgroup dg-name force including contents;
SQL> drop diskgroup dg-name force including contents;
·
Can mount the disk in restricted mode, to rebalance faster.
SQL> alter diskgroup dg-name mount restricted;
SQL> alter diskgroup dg-name mount restricted;
·
New commands in ASMCMD.
o
cp -
to copy between ASM and local or remote destination.
o
md_backup -
to backup metadata.
o
md_restore -
to restore metadata.
o
lsdsk -
to list(check) disks.
o
remap -
to repair a range of physical blocks on disk.
ASM New features in Oracle 11g
release2
·
ASM Configuration Assistant (ASMCA) is a new tool to install and
configure ASM.
·
ASM Cluster File System (ACFS) provides support for files such as
Oracle binaries, Clusterware binaries, report files, trace files, alert logs,
external files, and other application datafiles. ACFS can be managed by
ACFSUTIL, ASMCMD,
OEM, ASMCA, SQL command interface.
·
ASM Dynamic Volume Manager (ADVM) provides volume management
services and a standard device driver interface to its clients (ACFS, ext3,
OCFS2 and third party files systems).
·
ACFS Snapshots are read-only on-line, space efficient, point in
time copy of an ACFS file system. ACFS snapshots can be used to recover from
inadvertent modification or deletion of files from a file system.
·
ASM can hold and manage OCR (Oracle Cluster Registry) file and
voting file.
·
ASM diskgroups can be renamed, by using renamedg command.
·
ASMCMD utility can do
o
startup and
shutdown of ASM instances.
o
Managing diskgroups (create, mount, alter, drop).
o
File access control (like OS, ugo and rwx ...).
o
User management.
o
Template management.
o
Volume management.
o
We can execute OS commands at asmcmd by using !, in the same
we do at SQL prompt.
ASM New features in Oracle Clusterware 12c
1. Oracle Flex ASM - This feature of Oracle Clusterware 12c claims to reduce per-node overhead of using ASM instance. Now the instances can use remote node ASM for any planned/unplanned downtime. ASM metadata requests can be converted by non-local instance of ASM.
2. ASM Disk Scrubbing - From RAC 12c, ASM comes with disk scrubbing feature so that logical corruptions can be discovered. Also Oracle 12c ASM can automatically correct this in normal or high redundancy diskgroups.
3. Oracle ASM Disk Resync & Rebalance enhancements.
ASM Views
1. Oracle Flex ASM - This feature of Oracle Clusterware 12c claims to reduce per-node overhead of using ASM instance. Now the instances can use remote node ASM for any planned/unplanned downtime. ASM metadata requests can be converted by non-local instance of ASM.
2. ASM Disk Scrubbing - From RAC 12c, ASM comes with disk scrubbing feature so that logical corruptions can be discovered. Also Oracle 12c ASM can automatically correct this in normal or high redundancy diskgroups.
3. Oracle ASM Disk Resync & Rebalance enhancements.
ASM Views
The ASM configuration can be viewed using the V$ASM_% views, which
contain information depending on whether they are queried from the ASM
instance, or a dependant database instance.
View
|
In ASM instance
|
In DB instance
|
V$ASM_ALIAS
|
Displays
a row for each alias present in every diskgroup mounted by the ASM instance.
|
Returns
no rows.
|
V$ASM_ATTRIBUTE
(11gR2)
|
Displays
attributes of diskgroups.
|
Displays
attributes of diskgroups.
|
V$ASM_CLIENT
|
Displays
a row for each database instance using a diskgroup managed by the ASM
instance.
|
Displays
a row for the ASM instance if the database has open ASM files.
|
V$ASM_DISK
or V$ASM_DISK_STAT
|
Displays
a row for each disk discovered by the ASM instance, including disks which are
not part of any diskgroup.
|
Displays
a row for each disk in diskgroups in use by the database instance.
|
V$ASM_DISK_IOSTAT(11gR2)
|
Displays
IO statistics of
disks.
|
Displays
IO statistics of disks.
|
V$ASM_DISKGROUP
or V$ASM_DISKGROUP_STAT
|
Displays
a row for each diskgroup discovered by the ASM instance.
|
Displays
a row for each diskgroup mounted by the local ASM instance.
|
V$ASM_FILE
|
Displays
a row for each file for each diskgroup mounted by the ASM instance.
|
Displays
no rows.
|
V$ASM_FILESYSTEM (11gR2)
|
Displays
a row for each filesystem for each diskgroup mounted by the ASM instance.
|
Displays
no rows.
|
V$ASM_OPERATION
|
Displays
a row for each file for each long running operation executing in the ASM
instance.
|
Displays
no rows.
|
V$ASM_TEMPLATE
|
Displays
a row for each template present in each diskgroup mounted by the ASM
instance.
|
Displays
a row for each template present in each diskgroup mounted by the ASM
instance.
|
V$ASM_USER (11gR2)
|
Displays
a row for each ASM user.
|
-
|
V$ASM_USERGROUP (11gR2)
|
Displays
a row for each ASM usergroup.
|
-
|
V$ASM_USERGROUP_MEMBER(11gR2)
|
Displays
ASM usergroups and it's members.
|
-
|
V$ASM_VOLUME
orV$ASM_VOLUME_STAT(11gR2)
|
Displays
a row for each volume.
|
-
|
ASM backup can be taken by spooling the output of the ASM views to text file.
SPOOL asm_views.log
SET ECHO ON
SELECT * FROM V$ASM_ALIAS;
SELECT * FROM V$ASM_ATTRIBUTE;
SELECT * FROM V$ASM_ATTRIBUTE;
SELECT * FROM V$ASM_CLIENT;
SELECT * FROM V$ASM_DISK;
SELECT * FROM V$ASM_DISK_IOSTAT;SELECT * FROM
V$ASM_DISK_STAT;
SELECT * FROM V$ASM_DISKGROUP;
SELECT * FROM V$ASM_DISKGROUP_STAT;
SELECT * FROM V$ASM_FILE;
SELECT * FROM V$ASM_FILESYSTEM;
SELECT * FROM V$ASM_FILESYSTEM;
SELECT * FROM V$ASM_OPERATION;
SELECT * FROM V$ASM_TEMPLATE;
SELECT * FROM V$ASM_USER;
SELECT * FROM V$ASM_USERGROUP;
SELECT * FROM V$ASM_USERGROUP_MEMBER;
SELECT * FROM V$ASM_VOLUME;
SELECT * FROM V$ASM_VOLUME_STAT;
SELECT * FROM V$ASM_USERGROUP;
SELECT * FROM V$ASM_USERGROUP_MEMBER;
SELECT * FROM V$ASM_VOLUME;
SELECT * FROM V$ASM_VOLUME_STAT;
SPOOL OFF
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