> What is the
difference between HOTBACKUP and RMAN backup ?
For hotbackup we have to put database in begin backup mode, then take backup where as RMAN would not put database in begin backup mode. RMAN is faster can perform incremental (changes only) backup, and does not place tablespace in hotbackup mode.
For hotbackup we have to put database in begin backup mode, then take backup where as RMAN would not put database in begin backup mode. RMAN is faster can perform incremental (changes only) backup, and does not place tablespace in hotbackup mode.
> Can we use
Same target database as Catalog database ?
No, the recovery catalog should not reside in the target database (database to be backed up) because the database can not be recovered in the mounted state.
No, the recovery catalog should not reside in the target database (database to be backed up) because the database can not be recovered in the mounted state.
> Why RMAN
incremental backup fails even though full backup exists ?
If you have taken the RMAN full backup using the command 'Backup database', where as a level 0 backup is physically identical to a full backup. The only difference is that the level 0 backup is recorded as an incremental backup in the RMAN repository so it can be used as the parent for a level 1 backup. Simply the 'full backup without level 0' can not be considered as a parent backup from which you can take level 1 backup..
If you have taken the RMAN full backup using the command 'Backup database', where as a level 0 backup is physically identical to a full backup. The only difference is that the level 0 backup is recorded as an incremental backup in the RMAN repository so it can be used as the parent for a level 1 backup. Simply the 'full backup without level 0' can not be considered as a parent backup from which you can take level 1 backup..
> Can we
perform RMAN level 1 backup without level 0 ?
If no level 0 is available, then the behavior depends upon the compatibility mode setting (oracle version).
If the compatibility mode less than 10.0.0, RMAN generates a level 0 backup of files contents at the time of backup.
If the compatibility is greater than 10.0.0, RMAN copies all block changes since the file was created, and stores the results as level 1 backup.
If no level 0 is available, then the behavior depends upon the compatibility mode setting (oracle version).
If the compatibility mode less than 10.0.0, RMAN generates a level 0 backup of files contents at the time of backup.
If the compatibility is greater than 10.0.0, RMAN copies all block changes since the file was created, and stores the results as level 1 backup.
> How to put
Manual/User managed backup in RMAN ?
In case of recovery catalog, you can put by using catalog command:
RMAN> CATALOG START WITH '/oracle/backup.ctl';
In case of recovery catalog, you can put by using catalog command:
RMAN> CATALOG START WITH '/oracle/backup.ctl';
> How to check
RMAN version in oracle ?
If you want to check RMAN catalog version then use the below query from SQL*plus
SQL> Select * from rcver;
If you want to check RMAN catalog version then use the below query from SQL*plus
SQL> Select * from rcver;
> What happens
actually in case of instance Recovery ?
While Oracle instance fails, Oracle performs an Instance Recovery when the associated database is being re-started. Instance recovery occurs in 2 steps:
Cache recovery: Changes being made to a database are recorded in the database buffer cache as well as redo log files simultaneously. When there are enough data in the database buffer cache, they are written to data files. If an Oracle instance fails before these data are written to data files, Oracle uses online redo log files to recover the lost data when the associated database is re-started. This process is called cache recovery.
Transaction recovery: When a transaction modifies data in a database (the before image of the modified data is stored in an undo segment which is used to restore the original values in case the transaction is rolled back). At the time of an instance failure, the database may have uncommitted transactions. It is possible that changes made by these uncommitted transactions have gotten saved in data files. To maintain read consistency, Oracle rolls back all uncommitted transactions when the associated database is re-started. Oracle uses the undo data stored in undo segments to accomplish this. This process is called transaction recovery.
While Oracle instance fails, Oracle performs an Instance Recovery when the associated database is being re-started. Instance recovery occurs in 2 steps:
Cache recovery: Changes being made to a database are recorded in the database buffer cache as well as redo log files simultaneously. When there are enough data in the database buffer cache, they are written to data files. If an Oracle instance fails before these data are written to data files, Oracle uses online redo log files to recover the lost data when the associated database is re-started. This process is called cache recovery.
Transaction recovery: When a transaction modifies data in a database (the before image of the modified data is stored in an undo segment which is used to restore the original values in case the transaction is rolled back). At the time of an instance failure, the database may have uncommitted transactions. It is possible that changes made by these uncommitted transactions have gotten saved in data files. To maintain read consistency, Oracle rolls back all uncommitted transactions when the associated database is re-started. Oracle uses the undo data stored in undo segments to accomplish this. This process is called transaction recovery.
> When you
moved oracle binary files from one ORACLE_HOME server to another server then
which oracle utility will be used to make this new ORACLE_HOME usable ?
Relink all.
Relink all.
> In which
months oracle release CPU patches ?
JAN, APR, JUL, OCT
JAN, APR, JUL, OCT
> When we
applying single Patch, can you use opatch utility ?
Yes, you can use Opatch incase of single patch. The only type of patch that cannot be used with OPatch is a patchset.
Yes, you can use Opatch incase of single patch. The only type of patch that cannot be used with OPatch is a patchset.
> Is it
possible to apply OPATCH without downtime ?
As you know for apply patch your database and listener must be down. When you apply OPTACH it will update your current ORACLE_HOME. Thus coming to your question to the point in fact it is not possible without or zero downtime in case of single instance but in RAC you can Apply Opatch without downtime as there will be more separate ORACLE_HOME and more separate instances (running once instance on each ORACLE_HOME).
As you know for apply patch your database and listener must be down. When you apply OPTACH it will update your current ORACLE_HOME. Thus coming to your question to the point in fact it is not possible without or zero downtime in case of single instance but in RAC you can Apply Opatch without downtime as there will be more separate ORACLE_HOME and more separate instances (running once instance on each ORACLE_HOME).
> You have
collection of patch (nearly 100 patches) or patchset. How can you apply only
one patch from it ?
With Napply itself (by providing patch location and specific patch id) you can apply only one patch from a collection of extracted patch. For more information check the opatch util NApply –help. It will give you clear picture.
For Example:
opatch util napply <patch_location> -id 9 -skip_subset -skip_duplicate
This will apply only the patch id 9 from the patch location and will skip duplicate and subset of patch installed in your ORACLE_HOME.
With Napply itself (by providing patch location and specific patch id) you can apply only one patch from a collection of extracted patch. For more information check the opatch util NApply –help. It will give you clear picture.
For Example:
opatch util napply <patch_location> -id 9 -skip_subset -skip_duplicate
This will apply only the patch id 9 from the patch location and will skip duplicate and subset of patch installed in your ORACLE_HOME.
> What is ASM
in Oracle ?
Oracle ASM is Oracle's volume manager specially designed for Oracle database data. It is available since Oracle database version 10g and many improvements have been made in versions 11g release 1 and 2.
Oracle ASM is Oracle's volume manager specially designed for Oracle database data. It is available since Oracle database version 10g and many improvements have been made in versions 11g release 1 and 2.
ASM offers
support for Oracle RAC clusters without the requirement to install 3rd party
software, such as cluster aware volume managers or filesystems.
ASM is shipped as
part of the database server software (Enterprise and Standard editions) and
does not cost extra money to run.
ASM simplifies
administration of Oracle related files by allowing the administrator to
reference disk groups rather than individual disks and files, which are managed
by ASM.
The ASM
functionality is an extention of the Oracle Managed Files (OMF) functionality
that also includes striping and mirroring to provide balanced and secure
storage. The new ASM functionality can be used in combination with existing raw
and cooked file systems,along with OMF and manually managed files.
> Why should
we use separate ASM home ?
ASM should be installed separately from the database software in its own ORACLE_HOME directory. This will allow you the flexibility to patch and upgrade ASM and the database software independently.
ASM should be installed separately from the database software in its own ORACLE_HOME directory. This will allow you the flexibility to patch and upgrade ASM and the database software independently.
> How many ASM
instances should one have ?
Several databases can share a single ASM instance. So, although one can create multiple ASM instances on a single system, normal configurations should have one and only one ASM instance per system.
Several databases can share a single ASM instance. So, although one can create multiple ASM instances on a single system, normal configurations should have one and only one ASM instance per system.
For clustered
systems, create one ASM instance per node (called +ASM1, +ASM2, etc).
> How many
diskgroups should one have ?
Generally speaking one should have only one disk group for all database files – and, optionally a second for recovery files (see FRA).
Generally speaking one should have only one disk group for all database files – and, optionally a second for recovery files (see FRA).
> What is ASM
Rebalancing ?
The rebalancing speed is controlled by the ASM_POWER_LIMIT initialization parameter. Setting it to 0 will disable disk rebalancing.
ALTER DISKGROUP data REBALANCE POWER 11;
The rebalancing speed is controlled by the ASM_POWER_LIMIT initialization parameter. Setting it to 0 will disable disk rebalancing.
ALTER DISKGROUP data REBALANCE POWER 11;
> What happens
when an Oracle ASM diskgroup is created ?
When an ASM diskgroup is created, a hierarchialfilesystem structure is created.
When an ASM diskgroup is created, a hierarchialfilesystem structure is created.
> How does
this filesystem structure appear ?
Oracle ASM diskgroup'sfilesystem structure is similar to UNIX filesystem hierarchy or Windows filesystem hierarchy.
Oracle ASM diskgroup'sfilesystem structure is similar to UNIX filesystem hierarchy or Windows filesystem hierarchy.
> Where are
the Oracle ASM files stored ?
Oracle ASM files are stored within the Oracle ASM diskgroup. If we dig into internals, oracle ASM files are stored within the Oracle ASM filesystem structures.
Oracle ASM files are stored within the Oracle ASM diskgroup. If we dig into internals, oracle ASM files are stored within the Oracle ASM filesystem structures.
> How are the
Oracle ASM files stored within the Oracle ASM filesystem structure ?
Oralce ASM files are stored within the Oracle ASM filesystem structures as objects that RDBMS instances/Oracle database instance access. RDBMS/Oracle instance treats the Oracle ASM files as standard filesystem files.
Oralce ASM files are stored within the Oracle ASM filesystem structures as objects that RDBMS instances/Oracle database instance access. RDBMS/Oracle instance treats the Oracle ASM files as standard filesystem files.
> What are the
Oracle ASM files that are stored within the Oracle ASM file hierarchy ?
Files stored in Oracle ASM diskgroup/Oracl ASM filestructures include:
1) Datafile
2) Controlfiles
3) Server Parameter Files(SPFILE)
4) Redo Log files
Files stored in Oracle ASM diskgroup/Oracl ASM filestructures include:
1) Datafile
2) Controlfiles
3) Server Parameter Files(SPFILE)
4) Redo Log files
> What happens
when you create a file/database file in ASM?What commands do you use to create
database files ?
Some common commands used for creating database files are :
1) Create tabespace
2) Add Datafile
3) Add Logfile
For example,
SQL> CREATE TABLESPACE TS1 DATAFILE '+DATA1' SIZE 10GB;
Above command creates a datafile in DATA1 diskgroup
Some common commands used for creating database files are :
1) Create tabespace
2) Add Datafile
3) Add Logfile
For example,
SQL> CREATE TABLESPACE TS1 DATAFILE '+DATA1' SIZE 10GB;
Above command creates a datafile in DATA1 diskgroup
> How can you
access a databasefile in ASM diskgroup under RDBMS ?
Once the ASM file is created in ASM diskgroup, a filename is generated. This file is now visible to the user via the standard RDBMS view V$DATAFILE.
Once the ASM file is created in ASM diskgroup, a filename is generated. This file is now visible to the user via the standard RDBMS view V$DATAFILE.
> What will be
the syntax of ASM filenames ?
ASM filename syntax is as follows:
+diskgroup_name/database_name/database_file_type/tag_name.file_number.incarnation
where,
+diskgroup_name – Name of the diskgroup that contains this file
database_name – Name of the database that contains this file
datafile – Can be one among 20 different ASM file types
tag_name – corresponds to tablespace name for datafiles, groupnumber for redo log files
file_number – file_number in ASM instance is used to correlate filenames in database instance
incarnation_number – It is derived from the timestamp. IT is used to provide uniqueness
ASM filename syntax is as follows:
+diskgroup_name/database_name/database_file_type/tag_name.file_number.incarnation
where,
+diskgroup_name – Name of the diskgroup that contains this file
database_name – Name of the database that contains this file
datafile – Can be one among 20 different ASM file types
tag_name – corresponds to tablespace name for datafiles, groupnumber for redo log files
file_number – file_number in ASM instance is used to correlate filenames in database instance
incarnation_number – It is derived from the timestamp. IT is used to provide uniqueness
> What is an
incarnation number ?
An incarnation number is a part of ASM filename syntax. It is derived from the timestamp. Once the file is created, its incarnation number doesnot change.
An incarnation number is a part of ASM filename syntax. It is derived from the timestamp. Once the file is created, its incarnation number doesnot change.
> What is the
use of an incarnation number in Oracle ASM filename ?
Incarnation number distinguishes between a new file that has been created using the same file number and another file that has been deleted.
Incarnation number distinguishes between a new file that has been created using the same file number and another file that has been deleted.
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