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Oracle Automatic Storage Management (ASM)--------------------------------------- * An Oracle file system, built specifically for database related files.-- * Can be used for single or multiple instance architecture (RAC).-- (Eliminates the need for third party Clustered File System)-- * Enables storage solutions such as Striping & Mirroring (for performance & Survivability)-- * Stripes and Mirrors at file level (as opposed to volume level)-- - Files are striped more efficiently.-- - Mirroring can be enabled for specific files only, at different levels.-- * Each DB can have both ASM and regular files. (Can also migrate some files to ASM)-- * ASM can store all Oracle file types. (Not just Data Files).
ASM Advantages--------------------------------------- 1. it is aware of the nature of Oracle database files. This means it can make-- more intelligent decisions about how to manage the files than a third-party product.-- 2. ASM can handle files individually, whereas all other LVMs work at the-- volume level: they are not aware of the files within the volume. So with a third-party-- LVM, you have to specify RAID attributes per volume.-- ASM can specify the attributes per file, so you can for instance have three-way-- mirroring for your SYSTEM tablespace datafiles but no mirroring at all for your-- temporary tablespaces’ tempfiles, all within the same logical volume.
ASM Basic Concepts------------------------------------- ------------------------- * Disk Group (DG)------------------------- * A group of disks which are managed as a single logical unit:-- * If I need to add more space to a DG, I'll add another disk to it.-- * Although we may be constantly adding ASM Files and Disks to a growing system, the number of Disk Groups to manage remains constant.-- * ASM files are assigned to a Disk Group, instead of to a specific disk.-- * All data will be striped and mirrored between the disks of this DG.-- * DG >-< DB:-- * Each DG can contain files from multiple DBs.-- * Each DB can store his files on different DGs.-- * Each DG is self describing, and contains all information about his Disks and Files.
CREATE DISKGROUP DG3 '/devices/diskb3' NAME diskb3, '/devices/diskb4' NAME diskb4
Allocation Unit (AU)------------------------- *Each datafile is striped to Allocation Units (AU).-- * AUs are spread evenly across the disks of the Disk Group.-- * AUs are rebalanced automatically across the disks whenever disks are added or removed from the DG.-- * AU size:-- * 10g: 1MB-- * 11g: Determined at DG creation. (1MB, 2, 4, 8, 16, 32, 64MB)
CREATE DISKGROUP DG3 '/devices/diskb3' NAME diskb3, '/devices/diskb4' NAME diskb4ATTRIBUTE 'au_size'='4M';
ASM Instance------------------------- * ASM metadata is managed by a single ASM instance, which can serve many DBs and Instances.-- * The instance mounts his DGs instead of a specific database.-- * Created and configured via the DBCA. ("Configure ASM")-- * The instances, however, work directly with the ASM files.
Creating a Disk Group-- (Performed in the ASM instance)---------------------------------- conn /@ASM AS SYSASM -- See current Disk Groups:SELECT GROUP_NUMBER, NAME, TOTAL_MBFROM v$asm_diskgroup; col path for a50-- See available disks:SELECT GROUP_NUMBER "DG#", PATHFROM v$asm_diskORDER BY path; -- Join:SELECT GROUP_NUMBER, dg.name, SUM(d.TOTAL_MB) AS "Size", COUNT(*) AS "Disks"FROM v$asm_diskgroup dg JOIN v$asm_disk dUSING (GROUP_NUMBER)GROUP BY GROUP_NUMBER, dg.name ; -- Create a new disk group DG2:CREATE DISKGROUP DG2DISK'\\.\ORCLDISK_LABEL_G' NAME DG2_0,'\\.\ORCLDISK_LABEL_H' NAME DG2_1 ; -- See available disks:SELECT GROUP_NUMBER "DG#", PATHFROM v$asm_diskORDER BY path; -- DROP DISKGROUP DG2;
Create a tablespace with ASM file-- (Performed in the DB instance)
-------------------------------------conn sys/oracle@orcl as sysdba CREATE TABLESPACE ASM_TBS DATAFILE '+DG2/asm_tbs01.dbf' SIZE 100M; SELECT name FROM v$datafile; -- DROP TABLESPACE asm_tbs INCLUDING CONTENTS AND DATAFILES; -- * Stamp candidate disks / change name and creating disk groups can be done by using ASMCA-- $oracle_grid_home\BIN\asmca.bat-- * for stamping and name changing :-- SHUTDOWN ASM => stamp/change names => STARTUP ASM
ASM Templates------------------------------------- -- * A template is a collection of file attributes that are applied to the ASM files.-- It is associated with a Disk Group.-- * Whenever a file is created the file attributes specific to the template are applied to -- the files.-- * For eg., if we want to create a users tablespace that contains data file we use the-- DATAFILE template.-- * Default Template: When you create a disk group, Oracle creates system default template-- for the disk group.
Select * From V$ASM_TEMPLATE
ASM Striping--------------------------------------- * ASM stripes the file to AUs, and devides them between the DG disks.-- * Two types of striping:-- 1. Coarse-based striping:-- - Each stripe size is one AU.-- - Classic striping. Suitable for most file types.-- - Used for load balancing.-- 2. Fine-Grained striping-- - Each stripe size is 128KB. (Wider distribution of data)-- - Used for decreasing IO Latency (Waiting for IO).-- - Suitable for small IO operations such as Redo Log Files. ALTER DISKGROUP DG2 ATTRIBUTE 'template.tname.stripe' = 'COARSE', 'template.tname.redundancy' = 'MIRROR'; ALTER DISKGROUP dg2 MODIFY TEMPLATE ONLINELOGATTRIBUTES (FINE); ALTER DISKGROUP dg2 MODIFY TEMPLATE DATAFILEATTRIBUTES (COARSE);
Select * From V$ASM_TEMPLATEWHERE name = ('DATAFILE', 'ONLINELOG')AND group_number = 2
Disk Group Dynamic Rebalancing--------------------------------------- * ASM performs automatic rebalancing online whenever we add / remove disks from a DG.-- * ASM_POWER_LIMIT:-- - Controls IO overhead during rebalancing.-- - Values are between 1 and 11. (Minimum overhead (1) .. Minumum time (11))-- - The higher the limit, the faster rebalancing will complete.-- - Lower values will take longer, but consume fewer processing and I/O resources.
show parameter ASM_POWER_LIMIT
ASM Mirroring & Failure Groups--------------------------------------- * ASM can protect our files from media failures (disk / disk-controller crash)---- * Mirroring:-- - Applied at Extent (AU) level (Not at file or disk level).-- - When an AU is allocated to a file on a specific disk,-- a mirrored AU is also allocated on another disk in the SAME Disk Group.-- - Therefore, if a disk is lost, we can restore its contents-- from other disks on its Disk Group. -- * Failure Group:-- - A failure group is a subset of the disks in a disk group,-- which could fail at the same time because they share hardware.-- (For example, disks that share the same disk controller)-- - By default, each ASM disk belongs to his own Failure Group (FG).-- - However, we can group a few disks in a DG to a single Failure Group.-- - When an AU is allocated on a FG disk, a mirrored AU is also allocated-- on ANOTHER Failure Group in the SAME Disk Group.-- - Therefore, if a Failure Group is lost, we can restore its contents-- from other disks on its Disk Group. -- * types or mirroring:-- 1. External Redundancy - No mirroring or FGs. (When using an external tool for -- protection).-- 2. Normal Redundancy - Two-way mirroring. (Two copies)-- 3. High Redundancy - Triple-mirroring. (Three copies)
DROP DISKGROUP DG2 INCLUDING CONTENTS; -- A protected disk group:CREATE DISKGROUP DG2 NORMAL REDUNDANCY DISK '//./ORCLDISKDATA3' NAME DG2_0, '//./ORCLDISKDATA4' NAME DG2_1, '//./ORCLDISKDATA5' NAME DG2_2,
'//./ORCLDISKDATA6'; col name for a10col failgroup for a11col path for a20col redundancy for a10 SELECT GROUP_NUMBER "DG#", DISK_NUMBER "DSK#", NAME, FAILGROUP, PATH, OS_MB, TOTAL_MB, FREE_MBFROM v$asm_disk; DROP DISKGROUP DG2 INCLUDING CONTENTS; -- A Disk Group with 2 Failure Groups (one for each controller):CREATE DISKGROUP DG2 NORMAL REDUNDANCY FAILGROUP controller1 DISK '//./ORCLDISKDATA3' NAME DG2_0, '//./ORCLDISKDATA4' NAME DG2_1 FAILGROUP controller2 DISK '//./ORCLDISKDATA5' NAME DG2_2, '//./ORCLDISKDATA6' NAME DG2_3; col name for a10col failgroup for a11col path for a20col redundancy for a10 SELECT GROUP_NUMBER "DG#", DISK_NUMBER "DSK#", NAME, FAILGROUP, PATH, OS_MB, TOTAL_MB, FREE_MBFROM v$asm_disk;
ASM Instance Management------------------------------------- --------------------------------------- ASM initialization parameters--------------------------------------- * Important ASM related Parameters:-- - INSTANCE_TYPE : should be set to ASM. This is the only parameter that MUST be -- defined.-- - ASM_DISKGROUPS : List of disk groups to be mounted at startup.-- (Or during ALTER DISKGROUP ALL MOUNT)-- - ASM_POWER_LIMIT: The speed for a rebalance operation (1-11. default is 1).-- * Additional parameters can be set... --------------------------------------- ASM Shutdown / Startup------------------------------------- --------------- STARTUP--------------- * The options for the STARTUP command are:
-- - NOMOUNT - Starts the ASM instance without mounting any disk groups.-- - MOUNT - Starts the ASM instance and mounts the disk groups specified-- by the ASM_DISKGROUPS parameter.-- - FORCE - Performs a SHUTDOWN ABORT before restarting the ASM instance.-- - OPEN - Not a valid option.-- - RESTRICT- DB instances cannot use the DGs. (Used for maintenance) -- * If the ASM_DISKGROUPS parameter is empty, no DGs are mounted.-- (Can be mounted manually using ALTER DISKGROUP...MOUNT) --------------- SHUTDOWN--------------- * ASM instance shutdown is possible only after shutting down all instances connected to it-- (Otherwise: ORA-15097: cannot SHUTDOWN ASM instance with connected RDBMS instance) -- * The options for the SHUTDOWN command are:-- - NORMAL - Waits for all connections to finish (DB instances & SQL sessions)-- - TRANSACTIONAL - Waits for any active transactions to complete. (Doesn't wait for sessions)-- - IMMEDIATE - Same as TRANSACTIONAL.-- - ABORT - The ASM instance shuts down instantly (Crash). -- * Shutdown ABORT will require crash recovery upon next startup:-- - All connected instances will also shutdown.-- (ORA-15064: communication failure with ASM instance)-- - Each DG has log files for recovery of ASM metadata.-- - Actual data is recovered using the DB Redo Logs. -------------------------------- ASM Instance Architecture------------------------------------------------- MEMORY------------------- * SGA:-- - Shared Pool: Used for metadata information-- - Large Pool : Used for parallel operations-- - ASM Cache : Used for data blocks during rebalance operations-- - Free Memory: Unallocated memory available-- * Minimum recommended size is 256 MB. (Depends on the used disk space size)-- * AMM (Automatic memory management) is enabled by default. -------------------------------- Background Processes------------------------------------------------------- In the ASM instance------------------------- * The ASM instance contains some special ASM background processes:-- - RBAL - Manages the Rebalancing process across the DG.-- - ARBn - Perform the actual relocation of the AU during rebalancing.-- - GMON - (Group Monitor) - Disk-level activities (Offline, Drop etc).-- - MARK - Marks ASM allocation units as stale when needed
-- - Onnn - pool of connections to the ASM instance for exchanging messages ------------------------- In the DB instance------------------------- * In addition, each regular instance that uses ASM has some special background processes:-- - ASMB - Connects to the ASM instance at startup, and works with it (Data file management).
Common ASM V$ Views---------------------------------------------- V$ASM_FILE - Files of disk groups mounted by the ASM instance. SELECT file_number, name, ROUND(bytes/1024/1024) SIZE_MBFROM v$asm_alias JOIN v$asm_fileUSING (file_number)ORDER BY file_number, name; -- V$ASM_CLIENT - DB instances using the ASM instance.-- (In the DB - ASM instance data if the database has open ASM files) -- V$ASM_DISK - List of discovered Disks. (even if not part of any disk group).-- (In the DB - Disks of DGs used by the database instance).col name for a10col failgroup for a11col path for a20col redundancy for a10SELECT GROUP_NUMBER "DG#", DISK_NUMBER "DSK#", NAME, FAILGROUP, PATHFROM v$asm_diskORDER BY path; -- V$ASM_DISKGROUP - List of discovered disk groups.-- (In the DB - DGs mounted by the local ASM instance) -- V$ASM_OPERATION - Files with executing long running operations. -- V$ASM_TEMPLATE - Templates of DGs mounted by the ASM instance. -- V$ASM_ALIAS - Aliases that belong to mounted disk groups.-- - Files with aliases will have 2 rows. (Original & alias) SELECT file_number, name, CASE ALIAS_DIRECTORY WHEN 'Y' THEN 'Directory' ELSE 'File' END TypeFROM v$asm_aliasORDER BY type, file_number;
SYSASM--------------------------------------- * Meant for ASM management. (Separate from SYSDBA for security)-- * As ASM has no Data Dictionary, users are authenticated via OS or password-file.
-- * SYSOPER, enables basic administration, but not CREATE/ALTER/DROP DGs.-- (Startup/Shutdown, Mount/Dismount, Rebalance, Online/Offline disk, v$ASM_*)-- * SYSDBA enables all SYSASM privs, but will be limited in the future. -- * Via OEM (Only if connected via SYSASM):-- ASM => Users => Create/Edit/Delete-- (Connecting as SYSASM: Preferences => Preferred Credentials => ASM:Set Credentials => Specify...
-- In CMD:SET ORACLE_SID=+ASMsqlplus /nologconn / as sysasm SELECT GROUP_NUMBER, NAME, TOTAL_MBFROM v$asm_diskgroup; -- Or:CREATE USER asm_mgr IDENTIFIED BY asm_mgr;GRANT SYSASM TO asm_mgr;SELECT * FROM v$pwfile_users;conn asm_mgr/asm_mgr AS SYSASM
Interaction Between Database Instances and ASM------------------------------------- -- * The Database Instance and ASM Instance work together in a coordinated fashion.-- A Database instance must interact with ASM to map database files to ASM extents.-- * A Database instance also receives a constant stream of messages relating to ASM operations-- (such as disk group rebalancing) that may lock or move ASM extents.-- * Database I/O is not channeled through the ASM instance. In fact, the database conducts I/O-- operations directly against ASM files.
Disk Group Maintenance - SYNTAX...--------------------------------------- * Should be performed from the ASM instance by a user with a SYSASM privilege.
set oracle_sid=+ASMsqlplus / as sysasm col name for a10col path for a30 SELECT GROUP_NUMBER, NAME, STATE, TYPE, TOTAL_MBFROM V$ASM_DISKGROUPORDER BY 1; SELECT GROUP_NUMBER "DG#", DISK_NUMBER "DSK#", NAME, FAILGROUP, PATH, OS_MB, TOTAL_MB, FREE_MB
FROM v$asm_disk;
CREATE DG------------------------- * We can optionally name and size each disk.-- (Otherwise a system generated name is given, and ASM determines its size automatically)-- * FORCE - Move the disk from another DG to this one. CREATE DISKGROUP DG2 NORMAL REDUNDANCY DISK '//./ORCLDISKDATA3' NAME DG2_0, '//./ORCLDISKDATA4' NAME DG2_1, '//./ORCLDISKDATA5' NAME DG2_2, '//./ORCLDISKDATA6' NAME DG2_3;
DROP DG------------------------- * INCLUDING CONTENTS - Must be specified if it contains files.-- * The DG must be mounted, and its files inactive.-- * The header of each disk is formatted, so it will be available-- to other DGs or to the OS. DROP DISKGROUP DG2 INCLUDING CONTENTS;
Adding disks to a DG------------------------------- * Disks are added and Rebalaced online while data is fully accessible.-- * The rebalancing load is determined according to ASM_POWER_LIMIT. SELECT GROUP_NUMBER "DG#", DISK_NUMBER "DSK#", NAME, FAILGROUP, PATH, OS_MB, TOTAL_MB, FREE_MBFROM v$asm_diskWHERE group_number=0ORDER BY path; -- Add two disks to a "DG1":ALTER DISKGROUP DG1 ADD DISK '//./ORCLDISKDATA3' NAME DG1_3, '//./ORCLDISKDATA4' NAME DG2_4; -- Special discovery characters can be used to add a group of disks.ALTER DISKGROUP DG1 ADD DISK '//./ORCLDISKDATA*';
ASM DG Compatability-------------------------------- * Determines which Oracle version can run the ASM or work with him.-- * Determined at Disk Group level.-- * Two types:
-- 1. RDBMS Compatibility (Compatible.RDBMS)-- - Refers to the regular instances which work with the ASM.-- - The compatability version of the instance must be equal or higher.-- - Determines the format of the massages between the ASM and the regular instance.-- - ASM can operate with instances of different compatability versions.-- 2. ASM Compatability (Compatible.ASM)-- - The compatability version of the ASM instance (ASM Metadata).-- - Must be greater or equal to the RDBMS comp. of the FG. -------------------------------- ASM DG Attributes-------------------------------- * We can specify DG attributes when creating and altering the DG in the ATTRIBUTE clause.-- - AU_SIZE (C) - Allocation Unit size (1MB ,2, 4, 8, 16, 32, 64MB)-- - COMPATIBLE.RDBMS (AC) - Minimal Oracle version for the regular instances using the DG.-- - COMPATIBLE.ASM (AC) - Minimal Oracle version for the ASM instance mounting the DG.-- - DISK_REPAIR_TIME (AC) - Length of time before removing a disk once OFFLINE-- - TEMPLATE.t-name.REDUNDANCY (A) - Redundancy level of a specifid template.-- (UNPROTECTED / MIRROR / HIGH)-- - TEMPLATE.t-name.STRIPE (A) - Striping attribute of specified template. (COARSE / FINE)
ALTER DISKGROUP DG2ATTRIBUTE 'compatible.asm'='11.1'; -- * We can view all attributes of the DGs in the V$ASM_ATTRIBUTE view.-- * Via the OEM: Create/Edit DG => Advanced Attributescol name for a15col value for a10SELECT group_number DG#, name, valueFROM v$asm_attribute;
ASM Fast Mirror Resync---------------------------------- * Reduces the time required to resynchronize failed disk data.-- * When a disk goes offline due to a failure, his mirrored extents are still available.-- * ASM tracks the extents that were modified during the outage using a bitmap-- (Bit for each extent), and resynchronizes only these extents when the disk is back online.---- * When a disk becomes unavailable due to a failure, ASM places him OFFLINE automatically.-- * DISK_REPAIR_TIME - Determines the length of time before removing a disk once OFFLINE.-- (Length of outage which still enables auto-recovery of the disk).-- * To manually place a DG or FG Offline/Online via the OEM (For maintenance):-- - ASM Management => Click the DG usage pie-chart => View by disk/FG => Offline-- - We can override the default value of DISK_REPAIR_TIME here.
Bad block repair (11g)---------------------------------------------- * Performed automatically when in Normal/High Redundancy.
-- * When a block access fails, ASM recovers it automatically from its mirror.-- * If recovery to the original location fails, its recovered to an alternative location.-- * Can perform manually from ASMCMD using repair/remap.
Miscellaneous ALTER Commands---------------------------------------------- Remove a disk from a DG:ALTER DISKGROUP dgroupA DROP DISK A5; -- Removing and adding disks in a single statement (Efficient for rebalancing):ALTER DISKGROUP dgroupA DROP DISK A6 ADD FAILGROUP fred DISK '/dev/rdsk/c0t8d0s2' NAME A9; -- Cancel a disk drop operation (Only if the drop operationis not yet completed)ALTER DISKGROUP dgroupA UNDROP DISKS; -- Manually rebalance a DG:-- - Useful to change the default Power level.-- (Also for a rebalace that is already active in the background)-- - Setting the Power level to 0, stop the rebalancing.ALTER DISKGROUP dgroupB REBALANCE POWER 5; -- Mount/Dismount a DG:-- - Makes it unavailable to the DB.ALTER DISKGROUP DG1 DISMOUNT;ALTER DISKGROUP DG1 MOUNT;ALTER DISKGROUP ALL DISMOUNT;ASMCMD---------------------------------------------- * Manage ASM from the command prompt.-- * Works with ASM Files, Directories & Aliases.-- * Like other file systems, ASM also has directories which contain the ASM Files.-- * Each file has a "Fully Qualified File Name", which is the path to it:-- - The + sign represents the Root directory of the Disk Group:ASMCMD> ls -l +DGROUP1/ORCL/DATAFILE -- * mkdir - Add new directories:ASMCMD> mkdir +dgroup1/sample/mydir -- * md_backup / md_restore - backup and restore ASM Metadata:-- - This enables us to recreate a DG with the same directories and templates (attributes):ASMCMD> md_backup –b /tmp/dgbackup070222 –g admdsk1 –g asmdsk2ASMCMD> md_restore –t full –g asmdsk1 –i backup_file -- * lsdsk - Displays ASM disk information.-- - When connected - uses V$/GV$ tables.-- - When not-connected - scans the disk headers to get the information.-- (can use a disk string to limit the discovery set)
ASM Scalability and Performance-------------------------------------------- ---------------------------------------------- ASM Directories---------------------------------------------- * A directory heirarchy can be defined using the ALTER DISKGROUP statement-- to support ASM file aliasing: -- Create a directoryALTER DISKGROUP DG1 ADD DIRECTORY '+DG1/my_dir';ALTER DISKGROUP DG1 ADD DIRECTORY '+DG1/emps'; -- Rename a directory.ALTER DISKGROUP DG1 RENAME DIRECTORY '+DG1/emps' TO '+DG1/employees'; -- Delete a directory and all its contents.ALTER DISKGROUP DG1 DROP DIRECTORY '+DG1/employees';
Aliases-------------------------------------------- -- * Aliases allow you to reference ASM files using user-friendly names,-- rather than the fully qualified ASM filenames.-- *SELECT name FROM v$datafile; -- Create an alias using the fully qualified filename.ALTER DISKGROUP DG1 ADD ALIAS '+DG1/my_dir/my_file.dbf' FOR '+DG1/mydb/datafile/asm_tbs.256.718138495'; -- Create an alias using the numeric form filename.ALTER DISKGROUP DG1 ADD ALIAS '+DG1/my_dir/my_file.dbf' FOR '+DG1.256.718138495'; -- Rename an alias.ALTER DISKGROUP DG1 RENAME ALIAS '+DG1/my_dir/my_file.dbf' TO '+DG1/my_dir/my_file2.dbf'; -- Delete an alias.ALTER DISKGROUP DG1 DROP ALIAS '+DG1/my_dir/my_file2.dbf'; Attempting to drop a system alias results in an error
Create an ASM-based tablespace--------------------------------------------
conn /@orcl as sysdbaCREATE TABLESPACE ASM_TBS DATAFILE '+DG1/asm_tbs01.dbf' size 10m;ALTER TABLESPACE ASM_TBS ADD DATAFILE '+DG1' size 10m; SELECT name FROM v$datafile;
ASM Intallation Guidelines-------------------------------------------- -- 1. Using Third-Party tools such as EASEUS Partition Master 8.0.1 Home Edition-- Create Unallocated space on your hard drive-- 2. Create free space out of the anallocated space-- 3. Create at least 2 raw devices (without any file-system)-- 4. download Oracle Grid Infrastructure from oracle.com-- 5. Install Oracle Grid Infrastructure must be installed before Oracle Database-- NOTE : Oracle Grid Infrastructure must be installed before Oracle Database-- 6. Install Oracle Database -- * Networking (tnsnames / listener / sqlnet) should be configured in grid_home-- TNSNAMES.ORA Should look something like this:/*ORCL = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = OWNER-3WSG9BKMD)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = orcl) ) ) ASM = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = OWNER-3WSG9BKMD)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = +ASM) ) )*/ -- Listener should look something like this :/* SID_LIST_LISTENER = (SID_LIST = (SID_DESC = (SID_NAME = +ASM) (ORACLE_HOME = C:\app\Administrator\product\11.2.0\grid) ) ) LISTENER = (DESCRIPTION_LIST = (DESCRIPTION =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521)) (ADDRESS = (PROTOCOL = TCP)(HOST = OWNER-3WSG9BKMD)(PORT = 1521)) ) ) */
DEMO!------------------------------------------------ SQL*Plus: Release 11.2.0.1.0 Production on Thu Jul 21 08:04:08 2012 Copyright (c) 1982, 2010, Oracle. All rights reserved. @> conn /@ASM AS SYSASMConnected.SYS@ASM>SYS@ASM> -- See current Disk Groups:SYS@ASM> SELECT GROUP_NUMBER, NAME, TOTAL_MB 2 FROM v$asm_diskgroup; GROUP_NUMBER NAME TOTAL_MB------------ ------------------------------ ---------- 1 DG1 9998 SYS@ASM> col path for a50SYS@ASM> -- See available disks:SYS@ASM> SELECT GROUP_NUMBER "DG#", PATH 2 FROM v$asm_disk 3 ORDER BY path; DG# PATH---------- -------------------------------------------------- 1 \\.\ORCLDISK_LABEL_E 1 \\.\ORCLDISK_LABEL_F 0 \\.\ORCLDISK_LABEL_G 0 \\.\ORCLDISK_LABEL_H SYS@ASM>SYS@ASM> -- DG#=0 means that specific path does not have any Disk GroupSYS@ASM>SYS@ASM> -- Join:SYS@ASM> SELECT GROUP_NUMBER, dg.name, SUM(d.TOTAL_MB) AS "Size", COUNT(*) AS "Disks" 2 FROM v$asm_diskgroup dg JOIN v$asm_disk d 3 USING (GROUP_NUMBER) 4 GROUP BY GROUP_NUMBER, dg.name ; GROUP_NUMBER NAME Size Disks------------ ------------------------------ ---------- ---------- 1 DG1 9998 2 SYS@ASM>SYS@ASM> -- Create a new disk group DG2:SYS@ASM> CREATE DISKGROUP DG2
2 DISK 3 '\\.\ORCLDISK_LABEL_G' NAME DG2_0, 4 '\\.\ORCLDISK_LABEL_H' NAME DG2_1 ; Diskgroup created. SYS@ASM> -- See available disks:SYS@ASM> SELECT GROUP_NUMBER "DG#", PATH 2 FROM v$asm_disk 3 ORDER BY path; DG# PATH---------- -------------------------------------------------- 1 \\.\ORCLDISK_LABEL_E 1 \\.\ORCLDISK_LABEL_F 2 \\.\ORCLDISK_LABEL_G 2 \\.\ORCLDISK_LABEL_H SYS@ASM>SYS@ASM> -- DROP DISKGROUP DG2;SYS@ASM>SYS@ASM> -------------------------------------SYS@ASM> -- Create a tablespace with ASM fileSYS@ASM> -- (Performed in the DB instance)SYS@ASM> -------------------------------------SYS@ASM>SYS@ASM> conn sys/oracle@orcl as sysdbaConnected.SYS@orcl>SYS@orcl> CREATE TABLESPACE ASM_TBS 2 DATAFILE '+DG2/asm_tbs01.dbf' SIZE 100M; Tablespace created. SYS@orcl> SELECT name FROM v$datafile; NAME--------------------------------------------------------------------------------C:\APP\ADMINISTRATOR\ORADATA\ORCL\SYSTEM01.DBFC:\APP\ADMINISTRATOR\ORADATA\ORCL\SYSAUX01.DBFC:\APP\ADMINISTRATOR\ORADATA\ORCL\UNDOTBS01.DBFC:\APP\ADMINISTRATOR\ORADATA\ORCL\USERS01.DBFC:\APP\ADMINISTRATOR\ORADATA\ORCL\EXAMPLE01.DBF+DG2/asm_tbs01.dbf 6 rows selected. SYS@orcl>SYS@orcl> -- DROP TABLESPACE asm_tbs INCLUDING CONTENTS AND DATAFILES;SYS@orcl>SYS@orcl>SYS@orcl> -- * Stamp candidate disks / change name and creating disk groups can be done by using ASMCASYS@orcl> -- $oracle_grid_home\BIN\asmca.batSYS@orcl> -- * for stamping and name changing :
SYS@orcl> -- SHUTDOWN DB => SHUTDOWN ASM => stamp/change names => STARTUP ASM => STARTUP DBSYS@orcl> -- * SHUTDOWN ASM => stamp/change names => STARTUP ASMSYS@orcl> SYS@orcl> -------------------------SYS@orcl> -- ASM TemplatesSYS@orcl> -------------------------SYS@orcl>SYS@orcl> -- * A template is a collection of file attributes that are applied to the ASM files.SYS@orcl> -- It is associated with a Disk Group.SYS@orcl> -- * Whenever a file is created the file attributes specific to the template are applied toSYS@orcl> -- the files.SYS@orcl> -- * For eg., if we want to create a users tablespace that contains data file we use theSYS@orcl> -- DATAFILESYS@orcl> -- template.SYS@orcl> -- * Default Template: When you create a disk group, Oracle creates system default templateSYS@orcl> -- for the disk group.SYS@orcl> SYS@orcl> SELECT GROUP_NUMBER , NAME , STRIPE, REDUNDANCY 2 FROM V$ASM_TEMPLATE ; GROUP_NUMBER NAME STRIPE REDUND------------ ------------------------------ ------ ------ 1 PARAMETERFILE COARSE MIRROR 1 ASMPARAMETERFILE COARSE MIRROR 1 ASMPARAMETERBAKFILE COARSE MIRROR 1 DUMPSET COARSE MIRROR 1 CONTROLFILE FINE HIGH 1 FLASHFILE COARSE MIRROR 1 ARCHIVELOG COARSE MIRROR 1 ONLINELOG COARSE MIRROR 1 DATAFILE COARSE MIRROR 1 TEMPFILE COARSE MIRROR 1 BACKUPSET COARSE MIRROR GROUP_NUMBER NAME STRIPE REDUND------------ ------------------------------ ------ ------ 1 AUTOBACKUP COARSE MIRROR 1 XTRANSPORT COARSE MIRROR 1 CHANGETRACKING COARSE MIRROR 1 FLASHBACK COARSE MIRROR 1 DATAGUARDCONFIG COARSE MIRROR 1 OCRFILE COARSE MIRROR 1 OCRBACKUP COARSE MIRROR 1 ASM_STALE COARSE HIGH 2 PARAMETERFILE COARSE MIRROR 2 ASMPARAMETERFILE COARSE MIRROR 2 ASMPARAMETERBAKFILE COARSE MIRROR GROUP_NUMBER NAME STRIPE REDUND
------------ ------------------------------ ------ ------ 2 DUMPSET COARSE MIRROR 2 CONTROLFILE FINE HIGH 2 FLASHFILE COARSE MIRROR 2 ARCHIVELOG COARSE MIRROR 2 ONLINELOG COARSE MIRROR 2 DATAFILE COARSE MIRROR 2 TEMPFILE COARSE MIRROR 2 BACKUPSET COARSE MIRROR 2 AUTOBACKUP COARSE MIRROR 2 XTRANSPORT COARSE MIRROR 2 CHANGETRACKING COARSE MIRROR GROUP_NUMBER NAME STRIPE REDUND------------ ------------------------------ ------ ------ 2 FLASHBACK COARSE MIRROR 2 DATAGUARDCONFIG COARSE MIRROR 2 OCRFILE COARSE MIRROR 2 OCRBACKUP COARSE MIRROR 2 ASM_STALE COARSE HIGH 38 rows selected. SYS@orcl> SYS@orcl> ------------------------SYS@orcl> -- ASM StripingSYS@orcl> ------------------------SYS@orcl>SYS@orcl> -- * ASM stripes the file to AUs, and devides them between the DG disks.SYS@orcl> -- * Two types of striping:SYS@orcl> -- 1. Coarse-based striping:SYS@orcl> -- - Each stripe size is one AU.SYS@orcl> -- - Classic striping. Suitable for most file types.SYS@orcl> -- - Used for load balancing.SYS@orcl> -- 2. Fine-Grained stripingSYS@orcl> -- - Each stripe size is 128KB. (Wider distribution of data)SYS@orcl> -- - Used for decreasing IO Latency (Waiting for IO).SYS@orcl> -- - Suitable for small IO operations such as Redo Log Files.SYS@orcl>SYS@orcl> -- ONLINELOGSYS@orcl> ALTER DISKGROUP dg2 MODIFY TEMPLATE ONLINELOG 2 ATTRIBUTES (FINE); Diskgroup altered. SYS@orcl> ALTER DISKGROUP dg2 MODIFY TEMPLATE DATAFILE 2 ATTRIBUTES (COARSE); Diskgroup altered. 1 Select * From V$ASM_TEMPLATE 2 WHERE name IN ('DATAFILE', 'ONLINELOG')
3* AND group_number = 2SYS@orcl> / GROUP_NUMBER ENTRY_NUMBER REDUND STRIPE S NAME PRIM MIRR------------ ------------ ------ ------ - ------------------------------ ---- ---- 2 7 MIRROR FINE Y ONLINELOG COLD COLD 2 8 MIRROR COARSE Y DATAFILE COLD COLD SYS@orcl> SELECT GROUP_NUMBER , NAME , STRIPE, REDUNDANCY 2 FROM V$ASM_TEMPLATE 3 WHERE name IN ('DATAFILE', 'ONLINELOG') 4 AND group_number = 2 ; GROUP_NUMBER NAME STRIPE REDUND------------ ------------------------------ ------ ------ 2 ONLINELOG FINE MIRROR 2 DATAFILE COARSE MIRROR SYS@orcl>SYS@orcl> CONN /@ASM AS SYSASMSYS@ASM> DROP DISKGROUP DG2 INCLUDING CONTENTS;
ASM Mirroring & Failure Groups----------------------------------------------------------------------------------------------- * ASM can protect our files from media failures (disk / disk-controller crash)---- * Mirroring:-- - Applied at Extent (AU) level (Not at file or disk level).-- - When an AU is allocated to a file on a specific disk, a mirrored AU is also allocated on another disk in the SAME Disk Group.-- - Therefore, if a disk is lost, we can restore its contents from other disks on its Disk Group. -- * Failure Group:-- - A failure group is a subset of the disks in a disk group, which could fail at the same time because they share hardware. (For example, disks that share the same disk controller)-- - By default, each ASM disk belongs to his own Failure Group (FG).-- - However, we can group a few disks in a DG to a single Failure Group.-- - When an AU is allocated on a FG disk, a mirrored AU is also allocated on ANOTHER Failure Group in the SAME Disk Group.-- - Therefore, if a Failure Group is lost, we can restore its contents from other disks on its Disk Group. -- * types or mirroring:-- 1. External Redundancy - No mirroring or FGs. (When using an external tool for protection).-- 2. Normal Redundancy - Two-way mirroring. (Two copies)-- 3. High Redundancy - Triple-mirroring. (Three copies)
SYS@ASM> col path for a50SYS@ASM> -- See available disks:SYS@ASM> SELECT GROUP_NUMBER "DG#", PATH 2 FROM v$asm_disk 3 ORDER BY path; DG# PATH---------- -------------------------------------------------- 1 \\.\ORCLDISK_LABEL_E 1 \\.\ORCLDISK_LABEL_F 0 \\.\ORCLDISK_LABEL_G 0 \\.\ORCLDISK_LABEL_H -- A protected disk group: SYS@ASM> CREATE DISKGROUP DG2 1 NORMAL REDUNDANCY 2 DISK 3 '\\.\ORCLDISK_LABEL_G', 4 '\\.\ORCLDISK_LABEL_H' ; Diskgroup created. SYS@ASM> SELECT GROUP_NUMBER "DG#", DISK_NUMBER "DSK#", NAME, FAILGROUP 2 FROM v$asm_disk; DG# DSK# NAME FAILGROUP---------- ---------- ---------- ----------- 2 0 DG2_0000 DG2_0000 2 1 DG2_0001 DG2_0001 1 0 DG1_0000 DG1_0000 1 1 DG1_0001 DG1_0001 SYS@ASM> DROP DISKGROUP DG2 INCLUDING CONTENTS; Diskgroup dropped. SYS@ASM> CREATE DISKGROUP DG2 2 NORMAL REDUNDANCY 3 FAILGROUP controller1 DISK 4 '\\.\ORCLDISK_LABEL_G' 5 FAILGROUP controller2 DISK 6 '\\.\ORCLDISK_LABEL_H' ; Diskgroup created. SYS@ASM> SELECT GROUP_NUMBER "DG#", DISK_NUMBER "DSK#", NAME, FAILGROUP 2 FROM v$asm_disk; DG# DSK# NAME FAILGROUP---------- ---------- ---------- ----------- 2 0 DG2_0000 CONTROLLER1 2 1 DG2_0001 CONTROLLER2
1 0 DG1_0000 DG1_0000 1 1 DG1_0001 DG1_0001
