Oracle9i High Availability Frequently Asked Questions

General High Availability

• How does Oracle9i increase overall customer application availability? (15-MAY-01)
• Where do I go for additional high availability information? (22-MAY-01)
• What are the new Oracle9i high availability features? (23-MAY-01)

Recovery, Failover, and Cluster Solutions

• Does Transparent Application Failover work without Oracle Real Application Clusters and Oracle Parallel Server? (22-MAY-01)
• How does TAF (Transparent Application Failover) fail over end user connections transparently? (24-APR-00)
• What are the benefits of the Oracle Real Application Clusters and Oracle Parallel Server Primary/Secondary configuration? (22-MAY-01)
• Does TAF SELECT failover work with any type of database configuration (replication, standby, cold failover), or is OPS required? (22-MAY-01)
• With a cold failover solutions (Sun HA, HP ServiceGuard, IBM HACMP) is it best to install the Oracle binaries on internal disks local to each system, or on the shared disk. (08-JUN-00)
• What happened to Oracle Parallel Fail Safe in Oracle9i? (15-MAY-01)
• What improvements in the area of Fast Start Fault Recovery are in Oracle9i? (15-MAY-01)

Data Mangement and Reorganization

• What's the differences between defragmentation (coalescing) and re-organization (rebuilding, moving)? (22-MAY-01)
• What are the new Oracle9i online data reorganization capabilities? (22-MAY-01)
• What steps are involved in an online table redefinition? (22-MAY-01)
• When to use online index and IOT reorganization vs. online table redefinition? (22-MAY-01)

Data Protection and Disaster Recovery

• Can I use an Standard Edition (SE) standby database for an Enterprise Edition (EE) primary? (22-MAY-01)
• How does Oracle9i Data Guard differ from Oracle8i Data Guard? (15-MAY-01)

Database Administration and Management

• What's new in Oracle9i LogMiner? (15-MAY-01)
• What is the Flashback Query? (18-MAY-01)
• Does Flashback Query provide database and application level consistency? (18-MAY-01)
• Can Flashback Query be used as an historical/temporal database or for OLAP? (18-MAY-01)
• Where does Oracle get Flashback data from? (18-MAY-01)
• How far back can a Flashback Query go? (22-MAY-01)
• How can the Flashback Query feature be used? (23-MAY-01)
• How big should the undo tablespace be if I wish to retain undo data for a week? (22-MAY-01)
• Can I use the Flashback Query with manually created Rollback segments? (22-MAY-01)
• Do other database products have similar feature like Flashback Query? (22-MAY-01)

Storage Management

• What are VERITAS Quick I/O and Cached Quick I/O? Does Oracle support them? Do they work with RMAN? (23-MAY-01)
• Does Oracle work with network attached (i.e. NFS) file servers? (15-JUN-00)
• Is there any advantage in using Oracle partitioning with RAID 5? (15-JUN-00)
• Does Oracle support or certify any HSM systems? (23-MAY-01)
• With disk capacity growing at the rate of 100% every 15 months, the future of 100GB drives is not far away. In the same time frame, the rate of disk seek time throughput improvement is only 35%. How does a database administrator configure these large capacity disks for OLTP environment where IOPs (I/O per second), hence seek time, is more important? (23-MAY-01)
• Does Oracle support any asynchronous remote mirroring product? (22-MAY-01)
• What is the new Oracle9i Oracle Disk Manager (ODM) interface? (23-MAY-01)
• Does Oracle recommend any storage vendor or products? (22-MAY-01)
• Does Oracle recommend any storage configuration? What is the S.A.M.E. storage configuration? (30-MAY-01)
• What is Oracle Storage Compatibility Program (OSCP)? (22-MAY-01)
• Which vendors and products are in the OSCP? (22-MAY-01)
• Does Oracle certify disk, RAID, or other storage products? (22-MAY-01)
• What is a SAN? What is NAS? And how does Oracle fit in SAN and NAS? (23-MAY-01)
• What are the difference between RAID 5 and RAID 0+1? Which implementation is better? (30-MAY-01)

Database Resource Manager

• My customer would like to use Oracle's Database Resource Manager whilst also running an operating resource manager such has Sun's Solaris Resource Manager, or HP's Process Resource Manager. Are there any limitations? (15-JUN-00)
• What are the limitations when an Oracle instance is managed by a resource manager such as HP's Process Resource Manager or Sun's Solaris Resource Manager? (15-JUN-00)
• What are the limitations when an Oracle instance is managed by Sun's processor sets, dynamic system domains or dynamic reconfiguration (DR)? (15-JUN-00)
• What is the difference between Database Resource Manager's DEFAULT_CONSUMER_GROUP and OTHER_GROUPS? (15-JUN-00)
• It appears that the only way Database Resource Manager can be implemented is with an application designed so that each user has their own unique user id. Since most large applications run with one schema user, is Resource Manager practical for any¿ large application? (16-JUN-00)
• How does Oracle Database Resource Manager limit the allocation of resources to a consumer group? Is it like the UNIX "nice" command, which Oracle recommends against using? (15-JUN-00)
• Does Oracle support dynamic reconfiguration of the host system, for example, adding or taking resource without a system reboot. (16-JUN-00)
• How does Database Resource Manager use Adaptive Degree of Parallelism (ADOP)? For example: If I have a low priority user come in and spawn 6 PQ slaves and then a higher priority user comes by and needs more resources than available, what happens ? (16-JUN-00)
• What are the wait events associated with Database Resource Manager? (28-JUN-00)
• If a user is not in any group, what will happen to that user for CPU and Parallelism? (13-JUL-00)
• Does the Database Resource Manager work with Oracle Parallel Server and Real Application Clusters? (08-DEC-00)
• In Oracle9i Database Resource Manager, is the consumer group switch time based on elapsed time of a running query or on actual CPU time of that the query has used? (05-JUN-01)
• Has any thing been done in Oracle9i to improve the usability of the Database Resource Manager? (05-JUN-01)
• Does Oracle9i support OS level Dynamic Reconfiguration? (05-JUN-01)

Recovery Manager (RMAN)

• How does RMAN perform corruption detection? (16-NOV-00)
• Is there any method to encrypt a Recovery Manager(RMAN) backup while the backup is being written out to tape? (16-NOV-00)
• What do I need to do to be able to make RMAN backups to tape? (08-JUN-01)
• How does Legato LSM differ from Legato Networker (08-JUN-01)
• Can I have my target db on a sun box and the recovery catalog on a NT machine. (06-JUN-00)
• What is the recommended method for backing up the RMAN repository? (08-JUN-01)
• For an online backup, do you need to put tablespaces hot backup mode when using RMAN? (16-NOV-00)
• I have noticed the shadow (or server) processes spawned for "allocate channel" command wouldn't go away after rman completed and released the channel (at least the message in RMAN showed they were released), I noticed the shadow stayed for at least 8 minutes. I did wait for too long. As soon as I exit from rman, they disappeared. Were they waiting pmon to clean them up? How long does this usually take? (08-JUN-01)

• How many server sessions does RMAN use?
  How can the RMAN server sessions be identified?
  What is the purpose of each RMAN server sessions?
  When are the RMan server sessions released? (08-JUN-01)

• When performing a tablespace point in time recovery, are constraints automatically disabled after recovery is complete? (06-JUN-00)
• Can I still backup and recover an Oracle9i database using:
  
  alter ... begin backup
  dd of the file
  alter ... end backup
  recover database
  As well as manually backing up my archivelogs? (08-JUN-01)
• What is Recovery Manager (RMAN) and how do I get started? (16-NOV-00)
• How do you link a 3rd party Media Management Software with RMAN? (08-JUN-01)
• What is the difference between incremental and full RMAN backups? (16-NOV-00)
• When connecting to a target database with RMAN, how is a username and password validated? (16-NOV-00)
• How do you run a RMAN script using an OS file? (16-NOV-00)
• What are the Top 10 Reasons to integrate RMAN into your backup and recovery strategy? (08-JUN-01)
• Can RMAN backup Real Application Cluster databases? (22-MAY-01)
• Why should a DBA use a 3rd party software to backup their server files and then learn RMAN to backup their database? (08-JUN-01)
• Can I perform Block Media Recovery (BMR) if I did not use RMAN for backups? (22-MAY-01)
• Will the RMAN8i scripts continue to work with RMAN9i? (22-MAY-01)

New Search

Answers

Yes. Transparent Application Failover will work with a single instance configuration, any cluster failover product, or even geographically separate configurations like a standby database or a replicated database. However, only Oracle Parallel Server and replication support the pre-connect option of Transparent Application Failover. To use pre-connect, a user must be able to login to the backup instance at the time they connect to the primary instance.

The primary/secondary configuration masters locks at the primary instance. This has a number of advantages:

• at the primary instance, the communication with the DLM is fast as there is no latency across the interconnect, giving performance similar to single instance Oracle.
• the time to reconfigure the locks is faster as they are located locally, allowing use a larger number of releaseable hash locks than was recommended for primary/secondary pre-8.1.6 configurations. This allows the secondary instance to be used for secondary tasks including warming the cache.
• With local mastering there is minimal cost when the secondary instance leaves and rejoins the cluster.

In addition, Primary/Secondary configuration enforces primary/secondary access through the use of roles. This prevents unintended connections to the secondary instance.

TAF SELECT failover is supported with any type of database, Real Application Clusters or OPS is not required. A cluster failover (Fail Safe, ServiceGuard, FirstWatch, etc) would work just as well--it's the same database, just running on a different node. Also, SELECT failover will work with a replicated or standby database. However, because these databases are not identical to the primary database (a standby may be a few logs behind and a replicated database can have other records), the likelihood that the first n rows returned by the restarted query not corresponding to the n rows returned before the failure increases. Oracle (OCI library) detects this by calculating a checksum on those first n rows and comparing it to the running checksum it was calculating before the failure. If they are the same, Oracle assumes the first n rows are identical and discards those rows because they have already been returned. If they are not identical, Oracle returns an error message.

In theory, you can install Oracle binaries on either the internal local disks, or on the shared disks. We recommend installing on the local disks because:

• the shared disks are typically expensive resources ( RAID, mirrored, etc), and you may want to save these for your data.
• installing on the local disks provides redundancy (should the code tree become corrupted)
• installing on the local disks makes it simpler to do upgrades (upgrade the spare and fail over).

Of course, this requires a little more work than keeping the binaries on the shared disk. You only need install Oracle on one node, and then copy it to the other node. You will have to maintain two tnsnames.ora files (unless using some other means such as Oracle names, LDAP, nfs mounted files, etc).

Defragmentation or coalescing is an in-place data operation that compacts the data file and frees up unused disk space. No additional disk space is required during the compacting process. Oracle9i can defragment indexes in place.

Data re-organizations such as rebuilding indexes and moving a table or index requires additional temporary disk space during the re-organization process. These operations essentially make a new copy of the object. After the reorganization is complete, the original object is deleted and its disk space freed up. Oracle9i can re-organization indexes, partitioned indexes, IOTs and partitioned IOTs.

Both operations make tables and indexes more contiguous, free up disk space and improve database performance.

• ¿Index reorganization (create, rebuild, coalesce)
• Index-organized table reorganization (move)

Oracle recommends using online table redefinition feature for:

• ¿ Heap table reorganization¿
• ¿ Changing heap or IOT table physical or storage attributes (i.e. partition)
• ¿ Adding, dropping, and renaming columns in a table (normal drop column should be used for simple cases)
• ¿ Transforming data in a table
• ¿ When administrators want to validate data before completing a table redefinition or have control over when to complete a table redefinition (i.e. application upgrade)

No. This becomes and issue when customers star to use EE features like partitioning or wan to run the standby as a primary.

Also, this violates our pricing model and should not be done or suggested to the customer. Since a standby database is a block-for-block copy of the production database the standby database is the same flavor of Oracle -- e.g., SE or EE -- as the production system. See the following for clarification.

Production DB Type	Standby DB Type	Notes
EE	EE	Full Function
SE	SE	Without Automatic Log Shipping

VERITAS Quick I/O is a special feature of the VERITAS File System (VxFS) for the VERITAS Database Edition for Oracle.¿ The Database Edition is an integrated suite of system software enhancements and configuration guidelines that combine to help system administrators and database administors configure Oracle database servers.

VERITAS Quick I/O provides a raw device interface to regular files created under VxFS.¿ It bypasses certain file system overhead operations (i.e. locking layer) and supports kernel asynchronous I/O (KAIO),¿ hence Quick I/O provides the benefits of both file system manageability and raw device performance.¿ Cached Quick I/O is an enhancement to Quick I/O that enables Oracle DBAs to utilize their large system memories more effectively.

VERITAS has tested Quick I/O extensively with Oracle and supports the Database Edition directly.¿ Quick I/O does work with RMAN, there are some special steps to take during the restore operation.¿ They are documented in the VERITAS documentation.

You can find out more about the VERITAS product at:

http://www.veritas.com/us/products/oracleeditionsun/

Ultimately the disk configuration will be driven by IOPs (I/Os per second) requirement in an OLTP environment. For example, if the requirement is to be able to sustain 10,000 IOPs, and if each disk can provide 100 IOPs; then minimum 100 disks are required. This means some disk capacity may not be used.

Given that, there may be ways to optimize the configuration. 1. Stripe the data across all drives to maximize spindle utilization (in parallel) and reduce disk hot spots 2. Use outside portion of disk first to get better performance 3. Use inside portion of disk for online backup, which shouldn't be accessed during normal operation 4. Configure a large buffer cache

For availability reasons, Oracle also recommends mirroring all data and backing to tapes regularly.

Another option is to consider storage vendors that offer "high perfomance" or IOPs centric, small form factor disk, fast RPM disk, storage subsystems.

Yes.

Oracle Database Resource Manager can not run concurrently with Solaris Resource Manager. Results are unpredictable because neither "knows" about the other. But resource managers are justified based upon predictability!

• Each instance is assigned to a dedicated operating system resource manager group or managed entity.
• The dedicated entity running all the instance's processes must run at one priority (or resource consumption) level.
• Memory management and process management are not enabled.

NOTE: Management of individual Oracle processes at different priority levels is not supported. Severe consequences, including instance crashes, can result. You can get the same nasty results if SRM is permitted to manage memory on which an Oracle instance is pinned.

Processor sets & dynamic system domains with the Oracle database work well. Instance re-boot may be required solely when the number of CPU's is changed. Oracle discovers the number of CPU's when booting, and uses this for a number of algorithms for allocating resources (latches, lots of others). So if the number of CPU's changes (i. e., not a maintenance swap resulting in no change in the number of CPU's), rebooting may be required if performance suffers.

Dynamic Reconfiguration (DR)

CPU DR: Oracle can tolerate DR CPU changes. As with processor sets, a reboot may be required if the number of CPU's changes and performance suffers suffers as a result.

Memory DR: The Solaris DR-detach process that migrates memory is not supported.

If a user is not assigned to a user group, he/she is a member of DEFAULT_CONSUMER_GROUP. One reason for this consumer group is administrative time savings. For example, 25% of all users might be explicitly assigned to OLTP, with another 5% specified as members of the DSS group. The remaining 70% would already be members of the DEFAULT_CONSUMER_GROUP. If the remaining 70% should be prioritized similarly, and therefore managed as a single group, no more work is required to assign users to groups. Because of DEFAULT_CONSUMER_GROUP, everyone belongs to a group (either explicitly-assigned, or DEFAULT_CONSUMER_GROUP). Like all consumer groups, specifying the DEFAULT_CONSUMER_GROUP in the active plan is optional.

OTHER_GROUPS is not a group in that users can not be assigned to it. Users map to user groups one-to-one, and every user belongs to a group (DEFAULT or explicitly assigned, see above). When a group is not included in the active plan, its members default to the resources assigned to OTHER_GROUPS. To ensure that this "safety net" is always in place, and therefore that the administrator explicitly assigns resources to "everyone else", OTHER_GROUPS must be part of every plan.

Making a few changes to a complex application is the practical way to implement Database Resource Manager. As the Oracle Applications team proved in their 11i implementation, the changes did not require a redesign, nor lots of new code.

Since Oracle Applications starts a new session anytime responsibilities change (e.g., when accessing a different module), not much added effort was required to include the single-command (Database Resource Manager) procedure call to switch the session's consumer group assignment at session start-up. Oracle Applications required changes in just one place to integrate with Database Resource Manager. Oracle developers in the core applications infrastructure group implemented the required changes in libraries called by the various application modules.

The Oracle Applications Release 11i support is very granular. DBA's can associate an individual program to a resource consumer group or a group of programs to a resource consumer group. They can also associate a class of online users to a resource consumer group. For instance, they can say all "Order Entry" application users belong to consumer group 1 and "Human Resources" application users belong to consumer group 2.

At this point of time, we are not equipped to discover changes in the O/S resource allocation dynamically and hence may not be able to directly respond to it. For example, we discover the number of CPUs at the instance startup which used for allocation of internal resources like Redo Buffers and Latches. Other than that we are pretty much dependent on the O/S to distribute the load across the available CPUs and have no direct knowledge of how it is being done. So if you add a CPUs, O/S should be able to use it and to that extent Oracle may be get the benefit of additional horse power. However the instance's internal resources which are statically allocated at the time of startup would not change and therefore Oracle will not be able to full advantage of the additional CPU without instant bounce. Similarly, Oracle may continue to run if a CPU is taken away provided the O/S manages to relocate processes scheduled to run on this processor gracefully. Obviously there will be some degradation in the performance.

Oracle uses shared memory for its cache which is grabbed at the time of instance startup. You can not add or take away memory from Oracle's shared memory segment while a instance is running. If your hardware and O/S allows, you can add additional memory to your system but Oracle will not able to take advantage of it unless you shut the instance down, change the INIT.ORA parameters which control memory allocation e.g. db_block_buffers, shared_pool_size, large_pool etc. and start it back up.

All wait events associated with Resource Manager are prefixed with "resmgr:". For a complete listing of Resource manager events, execute the following query:

SELECT name from v$event_name where name like 'resmgr:%';



NAME

----------------------------------------------------------------

resmgr:wait in actses run

resmgr:waiting in end wait

resmgr:waiting in check

resmgr:waiting in system stop

resmgr:waiting in enter

resmgr:waiting in shutdown

resmgr:waiting in check2

resmgr:waiting in enter2

resmgr:waiting in run (queued)

resmgr:waiting in end wait2



10 rows selected.

Any user who is not assigned a consumer group explicitly automatically becomes a member of "DEFAULT_CONSUMER_GROUP" which is automatically created at the time of database set up. Thereafter an administrator has the option including this group in a resource plan if they want to assign resources to these users explicitly. Otherwise all the consumer groups which are not explicitly assigned resources in a resource plan share the resources allocated to "OTHER_GROUPS" (this one is automatically created as well). For this reason every valid plan must have a resource plan directive to allocate resources to "OTHER_GROUPS".

Note: Users can not be assigned to "OTHER_GROUPS" directly since it is not a regular consumer group. Think of it as a place holder for all the explicitly defined consumer groups in the database which is not included in the current (active) resource plan.

It is now possible to administer the Database Resource Manager using Oracle Enterprise Manager. The GUI will make it extremely easy to manage even the most complex Resource Manager implementations.

Oracle9i also allows users to quickly create a simple resource plan, adequate for most environments, using a single command (DBMS_RESOURCE_MANAGER.CREATE_SIMPLE_PLAN). This procedure significantly simplifies the creation of a resource plan as DBAs no longer need to execute different commands to create a pending area, create necessary consumer groups and specify resource allocation directives.

Corruption detection is actually performed by the Oracle server.

RMAN does NOT perform the backup, but the Oracle server. RMAN just directs the server to backup a specified list of datafiles. During backup, the Oracle server detects certain types of corruptions.

Many of the verification checks that are performed when a block is read into the buffer cache are also performed by a server process performing a backup. Some types of corruptions cannot be detected because the exact structure of table/index block distribution in the database object is unknown. Such information is unavailable to the server process performing the backup, and cannot be determined given that backups must be possible when the database is closed. If a block is detected as newly corrupted, it will be identified as such in the alert log and also in the database controlfile. You can view this information by querying the V$COPY_CORRUPTION or V$BACKUP_CORRUPTION views. If a block was already detected as corrupted by the server, then the block will not be identified in the same way as a newly corrupted block.

RMAN does not use an explicit encryption method, although the binary format of backup files offers some security.

The Media Management Vendor may offer encryption because of the security issue revolves around physical security of the media. The encryption may be a transport bit filtering option. All Media Manager's support some degree of security regarding who can load and read their tapes.

Note that the proprietary binary format of the backup output file from RMAN is not easily decipherable. To extract information from a datafile, you would have to have a copy of the same media management software and a copy of the media management backup catalog, and a in- depth knowledge of Oracle proprietary information. With the correct hardware, software, and knowledge it is theoretical possible. This security risk is not specific to the database. A customer has the same concerns with operating system backups of non-database files.

RMAN9i is not able to write directly to tape. As this is the case, Oracle has published an API specification which Media Management Vendor's who are members of Oracle's Backup Solutions Partner program have access to. Media Management Vendors (MMVs) then write an interface library which the Oracle9i server uses to write and read to and from tape. You need to have Media Management Server Software installed. You also need to have the interface library which is written by the Media Manager installed.

Oracle BSP Program Members

Here is how we recommend deploying the Recovery Catalog:

• It should be a separate database, not contained in any of the target databases whose backup data it contains.
• Create a new shema in the Enterprise Manager Database to house the Recovery Manager catalog
  
• High availability of the catalog can be achieved by any of the following techniques:
  • standy database
  • replication
  • maintaining two separate Recovery Catalog databases: one is kept in sync as it is used for everyday production operation, and the other is kept in sync manually, by periodically issuing the RESYNC CATALOG command.
• Use RMAN to back up the Recovery Catalog database, but for these backups, start RMAN with the NOCATALOG option, so that the backup repository for the Recovery Catalog is its own control file. The CONTROL_FILE_RECORD_KEEP_TIME parameter should be set to a value which is high enough to store an adequate amount of historical backup data for the Recovery Catalog.
  
• Back up the Recovery Catalog controlfile, so that you can restore it if you ever need to restore the Recovery Catalog.
  
  
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  For an online backup, do you need to put tablespaces hot backup mode when using RMAN?

  To understand why RMAN does not require extra logging or backup mode, you must first understand why those features are required for non-RMAN online backups.

  A non-RMAN online backup consists of a non-Oracle tool, such as cp or dd, backing up a datafile at the same time that DBWR is updating the file. We can't prevent the tool from reading a particular block at the exact same time that DBWR is updating that block. When that happens, the non-Oracle tool might read a block in a half-updated state, so that the block which is copied to the backup media might only have been updated in its first half, while the second half contains older data. This is called a "fractured block". If this backup needs to be restored later, and that block needs to be recovered, recovery will fail because that block is not usable.

  The 'alter tablespace begin backup' command is our solution for the fractured block problem. When a tablespace is in backup mode, and a change is made to a data block, instead of logging just the changed bytes to the redo log, we also log a copy of the entire block image before the change, so that we can reconstruct this block if media recovery finds that this block was fractured. That block image logging is what causes extra redo to be generated while files are in backup mode.

  The reason that RMAN does not require extra logging is that it guarantees that it will never back up a fractured block. We can make that guarantee because we know the format of Oracle data blocks, and we verify that each block that we read is complete before we copy it to the backup. If we read a fractured block, we read the block again to obtain a complete block before backing it up. non-Oracle tools are not able to do the same thing because they do not know how to verify the contents of an Oracle data block.

  Backup mode has another effect, which is to 'freeze' the checkpoint in the header of the file until the file is removed from backup mode. We do this because we cannot guarantee that the third-party backup tool will copy the file header prior to copying the data blocks. RMAN does not need to freeze the file header checkpoint because we know the order in which we will read the blocks, which enables us to capture a known good checkpoint for the file.

  
  [Top of Page]    Last Modified: 16-NOV-00    Ref #: 259

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  I have noticed the shadow (or server) processes spawned for "allocate channel" command wouldn't go away after rman completed and released the channel (at least the message in RMAN showed they were released), I noticed the shadow stayed for at least 8 minutes. I did wait for too long. As soon as I exit from rman, they disappeared. Were they waiting pmon to clean them up? How long does this usually take?

  Server processes for channels will not disappear until RMAN exists. The idea is that these processes will be reused for further backup jobs.

  
  [Top of Page]    Last Modified: 08-JUN-01    Ref #: 261

  ---

  How many server sessions does RMAN use?
  How can the RMAN server sessions be identified?
  What is the purpose of each RMAN server sessions?
  When are the RMan server sessions released?

  The number of RMAN server sessions can be calculated by the formula C+N+2, where:

  C is the number of allocated channels. These are used for backup and restore work. Server processes for channels will not disappear until rman exits. They will be re-used as necessary for further work.

  N is the number of distinct 'connect' options used on the allocate channel commands (or 1 if no connect options are used). One 'polling' session is opened at each node to query the status of the channels that are performing backup or restore work at this node.

  And the remaining 2 connections are:
  The 'default connection,' which performs action such as:
  -- recovery (application of redo)
  -- snapshot controlfile creation
  
  The connection to the recovery catalog.
  
  To check RMan processes, you would use normal operating system tools. Examples: On WinNT, the processes are easily found in the Task Manager. On Unix, you would use something like:
  
  $ ps -ef | grep rman
  osupport 12388 6982 0 13:25:11 pts/14 0:02 rman rcvcat
  $ ps -ef | grep 12388
  osupport 12396 12388 0 13:25:53 ? 0:00 oraclePROD
  osupport 12395 12388 0 13:25:52 ? 0:00 oraclePROD
  

  
  [Top of Page]    Last Modified: 08-JUN-01    Ref #: 264

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  When performing a tablespace point in time recovery, are constraints automatically disabled after recovery is complete?

  Constraints that straddle the recovery set must be disabled before the TSPITR has begun. Constraints within the recovery set are in the same state as at the time the tablespaces are recovered to.

  
  [Top of Page]    Last Modified: 06-JUN-00    Ref #: 265

  ---

  Can I still backup and recover an Oracle9i database using:
  
  alter ... begin backup
  dd of the file
  alter ... end backup
  recover database
  As well as manually backing up my archivelogs?

  Yes, this syntax is supported. This type of backup is called an User Managed backup. For more information, see the Oracle9i User Managed Backup and Recovery Guide.

  
  [Top of Page]    Last Modified: 08-JUN-01    Ref #: 270

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  What is Recovery Manager (RMAN) and how do I get started?

  See [NOTE:50875.1] in Metalink or WebIV.
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  ---

  How do you link a 3rd party Media Management Software with RMAN?

  1.Delete the old symbolic link for libobk.so:
  
  % rm $ORACLE_HOME/lib/libok.so
  
  2.Create a symbolic link between libobk.so and the shared library
  that you want to use. For example, on SunSolaris you can
  create the symbolic link libobk.so to a shared library such as
  liblsm.so using the ln command:
  
  % ln -s $ORACLE_HOME/lib/libobk.so $ORACLE_HOME/lib/liblsm.so
  

  
  [Top of Page]    Last Modified: 08-JUN-01    Ref #: 447

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  What is the difference between incremental and full RMAN backups?

  See [NOTE:69328.1].
  [Top of Page]    Last Modified: 16-NOV-00    Ref #: 449

  ---

  When connecting to a target database with RMAN, how is a username and password validated?

  First, let's take a look at how username and password is validated when connecting to SVRMGRL.

  • Example 1:
    SVRMGRL> connect foo/bar;
    # This has to work only if users are valid db user.
    # The db must be open.
    # Authentication path is through database.
  • Example 2:
    SVRMGRL> connect foo/bar as sysdba;
    # if SQL over sqlnet then check password file
    # if not over net then check UNIX user group if user
    # is in oracle dbs group.

  Now let's look at the RMAN connection.

  • Example 3:
    RMAN> connect catalog foo/bar;
    # Same like example 1 with SVRMGRL
    
  • Example 4:
    RMAN> connect target foo/bar;
    # Same like example 2 in SVRMGRL.
    # (we append AS SYSDBA to what user types)
  
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  How do you run a RMAN script using an OS file?

  There are two ways to do this.
  1. To run the script and connect in the same command (as you might want to do in a CRON job):
  rman target / nocatalog cmdfile "fullback.rmn"
  this will startup RMAN, connect to the target database, and run the script fullback.rmn
  
  2. If already in an RMAN session, from the RMAN prompt: @fullback.rmn
  
  You can find some sample scripts in $ORACLE_HOME/rdbms/demo. Search for rman*.sh.
  [Top of Page]    Last Modified: 16-NOV-00    Ref #: 451

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  What are the Top 10 Reasons to integrate RMAN into your backup and recovery strategy?

  • 10. Extensive Reporting
    RMAN reports provide analysis of your backup and recovery environment. An RMAN report answers the questions, "Is the database recoverable?" and "What do I need to do if it isn¿?".
  • 9. Incremental Backups
    Incremental backups provide shorter recovery time, saves backup storage, uses less bandwidth when backing up over a network, and provides the capability to recover objects created with the NOLOGGING option.
  • 8. Downtime Free Backups
    No need to ever shutdown the database to make online backups with RMAN. You set the schedule and RMAN will backup your database while never generating extra redo.
  • 7. Restore and Backup Validation
    Feel confident that the backups you made are good by rehearsing recovery to ensure it works.
  • 6. Backup and Restore Optimization
    Why subject your system to additional overhead? RMAN provides faster backup and restore times because it only does the work if it is required.
  • 5. Easily Integrated with Top Media Managers
    Learn and use RMAN directly or learn and use ONE tool to manage your backup and recovery strategy. The proxy copy feature utilized by the MML uses their new efficient technology for faster backups and restores.
  • 4. Block Media Recovery (BMR)
    BMR performs media recovery on individual blocks so less data is impacted by a failure. Increase data availability and reduce recovery time with RMAN and BMR.
  • 3. RMAN Knows Archive Logs
    RMAN backs up the datafiles and archive logs with one command while searching all destinations for valid archive logs to provide the ability to recover your data. RMAN automatically manages the archive log disk space by deleting logs once successfully backed up.
  • 2. Corrupt Block Detection
    During backup operations, corrupt blocks are detected and reported while preventing unusable backed up files.
  • 1. Trouble Free Backup and Recovery
    It¿ 4am and do you know what database files need to be restored? Prevent a bad situation from becoming worse. RMAN automates backup and recovery operations so all necessary database files are backed up and restores only the files required for recovery.
  
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  Can RMAN backup Real Application Cluster databases?

  Absolutely. RMAN can be configured to connect to all nodes within the cluster to parallelize the backup of the database files and archive logs. If files need to be restored, using set AUTOLOCATE ON alerts RMAN to search for backed up files and archive logs on all nodes.
  [Top of Page]    Last Modified: 22-MAY-01    Ref #: 532

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  Why should a DBA use a 3rd party software to backup their server files and then learn RMAN to backup their database?

  • One tool ¿ One Interface
  • Backup server files - Backup database
  • RMAN integration ensures that your database is precisely backed up

  Oracle BSP Program Members

  
  [Top of Page]    Last Modified: 08-JUN-01    Ref #: 533

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  Can I perform Block Media Recovery (BMR) if I did not use RMAN for backups?

  If you have image copies or OS backups of the datafiles you can perform BMR. You must first register the datafile image copies or OS backups to RMAN as well as the current archive log and all logs since the image backup time. This can be accomplished by using the RMAN CATALOG command.
  [Top of Page]    Last Modified: 22-MAY-01    Ref #: 534

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  Will the RMAN8i scripts continue to work with RMAN9i?

  Yes all of the RMAN8i commands work with RMAN9i. Oracle encourages DBAs to use the new configuration commands with the Oracle9i databases so the scripts will be more streamlined. As a side note, the command release channel is not required to be executed as RMAN will release channels implicitly.
  [Top of Page]    Last Modified: 22-MAY-01    Ref #: 535

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