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Add to Wish List. Introduction 1. Aim This dissertation is concerned with the language use of two Democratic politicians who are candidates for the United States presidential election of November 4 thnamely Hillary Clinton, senator for New York and Barack Obama, senator for Illinois. Medan University of Sumatera Utara. Kissine, Mikhail. She belongs to the Democratic.

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Alter system suspend resume

Some RAID devices benefit from suspending writes while the split operation is occurring; your RAID vendor can advise you on whether your system would benefit from this feature. Oracle Training from Don Burleson The best on site " Oracle training classes " are just a phone call away! You can get personalized Oracle training by Donald Burleson, right at your shop!

Burleson is the American Team Note: This Oracle documentation was created as a support and Oracle training reference for use by our DBA performance tuning consulting professionals. Feel free to ask questions on our Oracle forum. Verify experience! Anyone considering using the services of an Oracle support expert should independently investigate their credentials and experience, and not rely on advertisements and self-proclaimed expertise.

All legitimate Oracle experts publish their Oracle qualifications. You put your tablespaces into backup mode, alter system suspend IO -- use EMC software to "break" the mirrors into a pair and one singleton. You then resume IO on the mirrored pairs and the database continues on. You then backup the singleton set of disks at your leisure. Later, you "resilver" the 3'rd disk back into the mirror and away you go.

Very very specialized command for a particular implementation. Splitting the mirror involves separating the copies so that you can use them independently of one another. Some RAID devices benefit from suspending writes while the split operation is occurring; your RAID vendor can advise you on whether your system would benefit from this feature.

You can also catch regular content via Connor's blog and Chris's blog. Or if video is more your thing, check out Connor's latest video and Chris's latest video from their Youtube channels. And of course, keep up to date with AskTOM via the official twitter account. Question and Answer. Nystel, December 15, - pm UTC. If yes then what process and what activity is it performing against the files?

December 16, - am UTC. DBWR -- flushing blocks. LGWR -- flushing redo buffers every 3 seconds CKPT -- updating datafile headers constrol files getting written to every 3 seconds at least It would really help if you could explain with examples. December 16, - pm UTC. LGWR -- flushes redo from your update after a bit CKPT -- signalled by end of checkpoint to update datafile headers SMON wakes up and coalesces free space, generating log, dirty blocks and eventually causing a checkpoint. SMON does tons in the background -- all of the time.

Datafiles are constantly being written to, even when "nothing is happening". Nystel, December 16, - pm UTC. If there is no database activity then what information is being written into the control files every three seconds? If the redo log buffers are not written to since database is not active , then what is the reason to flush the redo log buffers? Does that mean when there is no db activity still we will see online redo log file switched at the same frequency since redo log buffers gets flushed to online redo log files?

December 17, - am UTC. SMON is doing stuff. SMON is generating redo. SMON is just one of them, SNPn's, intermedia, AQ, many other background processes out there with the potential to do stuff redo logs will only switch as they fill -- smon may eventually fill one and switch it sure. Tom, When the database was put into suspend mode alter system suspend; then any kind of activities being happened to redo logs and control files?? Alter tablespace user begin backup; 2.

Alter system suspend; 3. January 21, - pm UTC.

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December 17, - am UTC. SMON is doing stuff. SMON is generating redo. SMON is just one of them, SNPn's, intermedia, AQ, many other background processes out there with the potential to do stuff redo logs will only switch as they fill -- smon may eventually fill one and switch it sure.

Tom, When the database was put into suspend mode alter system suspend; then any kind of activities being happened to redo logs and control files?? Alter tablespace user begin backup; 2. Alter system suspend; 3. January 21, - pm UTC. The only way to get "consistent" and here consistent is not a goal, not a "good" thing is a cold backup after a normal or immediate shutdown. Those are normal good, desirable fuzzy hot backups. A reader, September 16, - pm UTC. Sorry I think I misplaced the link.

Hey Tom, 1. Can you please explain how three way mirrors work, in essence how is the database consistency achieved? Also: 2. On idle db: We had a simple test, we had a dummy database rnning for three days, doing nothing, it was just there, no queries, no dml nothing whatsoever. Was curios, if something being written to, I thought our backup shouldn't have worked at all! Please help! Really appreciate your inputs.

September 02, - am UTC. We do it by simply maintaining 1 or 2 copies mirror or triple mirror of extents on different failure groups. My question is regarding backgroung processes. Thanks in advance. September 24, - am UTC.

What is an acceptable period of time between the suspend and the resume command? Making a snapshot wil take some minutes. March 04, - am UTC. Version 10g Release 2 and 11g Releae 1. Please confirm this statement. Can I copy all the above three type of files in this state to another machine and startup the database at that new machine. October 15, - pm UTC.

It is not really intended for copying the entire database while suspended - the database will appear totally broken to everyone - it would be a 'bad idea'. If shutdown was possible for us, I didnt need to ask this question, but we dont want to shutdown the database for some reason. I understand its for BCV, but I just want to know that, are all control files , datafiles and online redolog files on disk are freezed after suspend? Please give answer of this specifically.

To use this clause, your instance must have the database open. In a single-process environment, you must use this clause to initiate distributed recovery. The shared pool stores:. You can use this clause regardless of whether your instance has the database dismounted or mounted, open or closed. This clause is intended for use only on a test database. Do not use this clause on a production database, because as a result of this statement, subsequent queries will have no hits, only misses.

This clause is useful if you need to measure the performance of rewritten queries or a suite of queries from identical starting points. This clause can be useful if you need to measure the performance of rewritten queries or a suite of queries from identical starting points, or if there might be corruption in the cache. Use the FLUSH REDO clause to flush redo data from a primary database to a standby database and to optionally wait for the flushed redo data to be applied to a physical or logical standby database.

This clause can allow a failover to be performed on the target standby database without data loss, even if the primary database is not in a zero data loss data protection mode, provided that all redo data that has been generated by the primary database can be flushed to the standby database. You must specify this clause if the target standby database is a snapshot standby database. You cannot specify this clause if the target standby database is a snapshot standby database.

Your session and the session to be terminated must be on the same instance unless you specify integer3. If the session is performing some activity that must be completed, such as waiting for a reply from a remote database or rolling back a transaction, then Oracle Database waits for this activity to complete, marks the session as terminated, and then returns control to you.

If the waiting lasts a minute, then Oracle Database marks the session to be terminated and returns control to you with a message that the session is marked to be terminated. The PMON background process then marks the session as terminated when the activity is complete. Whether or not the session has an ongoing transaction, Oracle Database does not recover the entire session state until the session user issues a request to the session and receives a message that the session has been terminated.

This clause is valid if you are using Application Continuity. When you force a log switch, Oracle Database begins to perform a checkpoint but returns control to you immediately rather than when the checkpoint is complete. An attempt to reconnect while the system is suspended may fail because of recursive SQL that is running during the SYS login. If you start a new instance while the system is suspended, then that new instance will not be suspended. For all instances with the database open, this clause has the following effect:.

If a query is carried out by multiple successive OCI fetches, then Oracle Database does not wait for all fetches to finish. It waits for the current fetch to finish and then blocks the next fetch. If an instance is running in non-shared-server mode, then Oracle Database does not impose any restrictions on user logins in that instance.

The surrounding single quotation marks are required. Oracle ASM first verifies that the current release is compatible for migration to the specified release, and then goes into limited functionality mode. Oracle ASM then determines whether any rebalance operations are under way anywhere in the cluster.

If there are any such operations, then the statement fails and must be reissued after the rebalance operations are complete. Rolling upgrade mode is a cluster-wide In-Memory persistent state. The cluster continues to be in this state until there is at least one Oracle ASM instance running in the cluster.

Any new instance joining the cluster switches to migration mode immediately upon startup. If all the instances in the cluster terminate, then subsequent startup of any Oracle ASM instance will not be in rolling upgrade mode until you reissue this statement to restart rolling upgrade of the Oracle ASM instances.

Use this clause to stop rolling upgrade and bring the cluster back into normal operation. Specify this clause only after all instances in the cluster have migrated to the same software version. The statement will fail if the cluster is not in rolling upgrade mode.

When you specify this clause, the Oracle ASM instance validates that all the members of the cluster are at the same software version, takes the instance out of rolling upgrade mode, and returns to full functionality of the Oracle ASM cluster.

Oracle Automatic Storage Management Administrator's Guide for more information about rolling upgrade. Use this clause to start the rolling patch operation. Oracle ASM first verifies that all live nodes in the cluster are at the same version, and then goes into rolling patch mode, which is a cluster-wide In-Memory persistent state.

The cluster continues to be in this state until all live nodes have been patched to the latest patch level. Any nodes that are down during this operation are not patched. This does not affect the success of the rolling patch operation. However, you must patch these nodes before they are started. Otherwise, they will not be allowed to join the cluster. Specify this clause only after all live nodes in the cluster have been patched to the latest patch level. The statement will fail if the cluster is not in rolling patch mode.

When you specify this clause, the Oracle ASM instance validates that all members of the cluster are at the same patch level, takes the instance out of rolling patch mode, and returns full functionality of the Oracle ASM cluster. If any members of the cluster are not at the latest patch level, then this operation fails and the cluster goes into limited functionality mode.

The following queries display information about rolling patches. Refer to Oracle Database Reference for more information. Oracle Automatic Storage Management Administrator's Guide for more information about rolling patches. They also allow you to enable or disable access to the encrypted data in the instance. Existing sessions are not terminated. This clause applies only to the current instance. However, you cannot roll back such a statement. When you specify this clause, the database uses the specified password to open the wallet and load the TDE master key into database memory for the duration of the instance, or establish a connection to the HSM in order to send the encrypted table and tablespace keys to the HSM and receive then back decrypted.

If the wallet is not available or is already open, then the database returns an error. Use this clause to disable encryption and decryption in your database. A password is not required to close an auto-open wallet when only an auto-open wallet is present. The password is required to close an auto-open wallet when both an auto-open wallet and an encryption wallet are open. Use this clause to generate a new TDE master encryption key, if none exists.

If there are existing master keys in the HSM or keystore, then this clause rekeys the existing table and tablespace keys, that is, it decrypts all table and tablespace keys with the old master key and reencrypts them with the new master key. This clause loads the TDE master encryption key from the encryption wallet into memory for access to encrypted data. Specify the integer that identifies the certificate.

This clause creates a master encryption key that will be stored inside the HSM. The master encryption key is used to encrypt or decrypt table keys inside the HSM. This decrypts the existing table and tablespace keys, and then reencrypts them with the newly created, HSM-based, master encryption key.

Note that the wallet is still in use after you migrate to an HSM, because it may contain master encryption keys that were used for export files, RMAN backups, or encrypted data in temporary or undo tablespaces or redo log files. After migrating, perform one of the following steps:. Do not delete the encryption wallet and do not forget the wallet password. Instead of using Oracle Wallet Manager, Oracle recommends that you use the command line tools orapki and mkstore.

After all sessions are cleaned up, the dispatcher process shuts down. If you do not specify IMMEDIATE , then the dispatcher stops accepting new connections immediately but waits for all its users to disconnect and for all its database links to terminate.

Then it shuts down. If you do not specify this clause, then registration of the instance does not occur until the next time PMON executes the discovery routine. As a result, clients may not be able to access the services for as long as 60 seconds after the listener is started.

This clause allows you to change parameter values. You can change the value of many initialization parameters for the current instance, whether you have started the database with a traditional plain-text parameter file pfile or with a server parameter file spfile. Oracle Database Reference indicates these parameters in the "Modifiable" category of each parameter description.

If you are using a pfile, then the change will persist only for the duration of the instance. However, if you have started the database with an spfile, then you can change the value of the parameter in the spfile itself, so that the new value will occur in subsequent instances.

Oracle Database Reference documents all initialization parameters in full. The parameters fall into three categories:. Basic parameters: Database administrators should be familiar with and consider the setting for all of the basic parameters.

Functional categories: Oracle Database Reference also lists the initialization parameters by their functional category. Alphabetical listing: The Table of Contents of Oracle Database Reference contains all initialization parameters in alphabetical order. The ability to change initialization parameter values depends on whether you have started up the database with a traditional plain-text initialization parameter file pfile or with a server parameter file spfile.

Managing Security for Oracle Databases. The comment string cannot contain control characters or a line break. If you also specify SPFILE , then this comment will appear in the parameter file to indicate the most recent change made to this parameter.

Current sessions retain the old value. A CDB uses an inheritance model for initialization parameters in which PDBs inherit initialization parameter values from the root. In this case, inheritance means that the value of a particular parameter in the root applies to a particular PDB. A PDB can override the root's setting for some parameters, which means that a PDB has an inheritance property for each initialization parameter that is either true or false.

The inheritance property is true for a parameter when the PDB inherits the root's value for the parameter. The inheritance property is false for a parameter when the PDB does not inherit the root's value for the parameter. The inheritance property for some parameters must be true.

The current container must be the root. When the current container is the root, the parameter setting applies to the root and to any PDB with an inheritance property of true for the parameter. MEMORY indicates that the change is made in memory, takes effect immediately, and persists until the database is shut down. If you started up the database using a parameter file pfile , then this is the only scope you can specify.

The new setting takes effect when the database is next shut down and started up again. BOTH indicates that the change is made in memory and in the server parameter file. The new setting takes effect immediately and persists after the database is shut down and started up again. If a server parameter file was used to start up the database, then BOTH is the default.

If a parameter file was used to start up the database, then MEMORY is the default, as well as the only scope you can specify. The initialization parameter value takes effect only for the PDB.

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Burleson is the American Team Note: This Oracle documentation was created as a support and Oracle training reference for use by our DBA performance tuning consulting professionals. Feel free to ask questions on our Oracle forum. Verify experience! Anyone considering using the services of an Oracle support expert should independently investigate their credentials and experience, and not rely on advertisements and self-proclaimed expertise.

All legitimate Oracle experts publish their Oracle qualifications. Oracle technology is changing and we strive to update our BC Oracle support information. If you find an error or have a suggestion for improving our content, we would appreciate your feedback. Just e-mail: and include the URL for the page. For example, run the following query:. Back up one copy of each log sequence number by using an operating system utility.

This example backs up all logs in the primary archiving location to a disk devoted to log backups:. Some third-party tools allow you to mirror a set of disks or logical devices, that is, maintain an exact duplicate of the primary data in another location, and then split the mirror.

Splitting the mirror involves separating the copies so that you can use them independently. Some RAID devices benefit from suspending writes while the split operation is occurring; your RAID vendor can advise you on whether your system would benefit from this feature. After a successful database suspension, you can back up the database to disk or break the mirrors.

You must use conventional user-managed backup methods to back up split mirrors. RMAN cannot make database backups or copies because these operations require reading the data file headers. Backing up a suspended database without splitting mirrors can cause an extended database outage because the database is inaccessible during this time. If backups are taken by splitting mirrors, however, then the outage is nominal. The outage time depends on the size of cache to flush, the number of data files, and the time required to break the mirror.

In an Oracle RAC configuration, you should not start a new instance while the original nodes are suspended. This prevents media recovery or failure recovery from getting into a unresponsive state. Place the database tablespaces in backup mode. For example, to place tablespace users in backup mode, enter:. If your mirror system has problems with splitting a mirror while disk writes are occurring, then suspend the database. For example, issue the following statement:. End the database suspension.

Take the specified tablespaces out of backup mode. For example, enter the following statement to take tablespace users out of backup mode:. A raw device is a disk or partition that does not have a file system. A raw device can contain only a single file. Backing up files on raw devices poses operating system specific issues. The dd command on Linux and UNIX is the most common backup utility for backing up to or from raw devices.

See your operating system-specific documentation for complete details about this utility. Using dd effectively requires that you specify the correct options, based on your database. Table lists details about your database that affect the options you use for dd. Table Aspects of the Database Important for dd Usage.

You can specify the size of the buffer that dd uses to copy data. For example, you can specify that dd should copy data in units of 8 KB or 64 KB. The block size for dd need not correspond to either the Oracle block size or the operating system block size: it is the size of the buffer used by dd when making the copy.

On some systems, the beginning of the file on the raw device is reserved for use by the operating system. This storage space is called the raw offset. Oracle should not back up or restore these bytes. At the beginning of every Oracle database file, the operating system-specific code places an Oracle block called block 0. The generic Oracle code does not recognize this block, but the block is included in the size of the file on the operating system. Typically, this block is the same size as the other Oracle blocks in the file.

The information in Table enables you to set the dd options specified in Table Table Options for dd Command. The number of dd buffers to skip on the input raw device if a raw offset exists. The number of dd buffers to skip on the output raw device if a raw offset exists. The number of blocks on the input raw device for dd to copy.

It is best to specify the exact number of blocks to copy when copying from a raw device to a file system; otherwise extra space at the end of the raw volume that is not used by the Oracle data file is copied to the file system. Remember to include block 0 in the total size of the input file.

Because a raw device can be the input or output device for a backup, you have four possible scenarios for the backup. The possible options for dd depend on which scenario you choose, as illustrated in Table Table Scenarios Involving dd Backups. You set the dd block size to 8 KB when a raw device is involved in the copy. Like Linux and UNIX, Windows supports raw disk partitions in which the database can store data files, online logs, and control files.

Each raw partition is assigned either a drive letter or physical drive number and does not contain a file system. On Windows, raw data file names are formatted as follows:. The procedure for making user-managed backups of raw data files is basically the same as for copying files on a Windows file system, except that you should use the Oracle OCOPY utility rather than the Windows-supplied copy. Sample output follows:. Splits the input file into multiple output files.

This option is useful for backing up to devices that are smaller than the input file. Combines multiple input files and writes to a single output file. This option is useful for restoring backups created with the -b option. To back up the data file onto drive E: , you can execute the following command at the Windows prompt after placing data file 7 in backup mode:. When drive E: fills up, you can use another disk.

In this way, you can divide the backup of data file 7 into multiple files. Similarly, to restore the backup, take the tablespace containing data file 7 offline and run this command:. You can use these applications to create snapshots of database files managed by the Oracle instance. You should periodically verify your backups to ensure that they are usable for recovery. The best way to test the usability of data file backups is to restore them to a separate host and attempt to open the database, performing media recovery if necessary.

This option requires that you have a separate host available for the restore procedure. Use DBVERIFY to ensure that a user-managed backup of a data file is valid before it is restored or as a diagnostic aid when you have encountered data corruption problems. For example, to perform an integrity check on data file users Caution: Never back up online redo log files. For example, the following query displays which data files are currently included in a tablespace that has been placed in backup mode: SELECT t.

TS AND b. See Also: Oracle Database Administrator's Guide for more information about starting up and shutting down a database. Making User-Managed Backups of Tablespaces and Data Files The technique for making user-managed backups of tablespaces and data files depends on whether the files are offline or online.

Making User-Managed Backups of Online Tablespaces and Data Files You can back up all or only specific data files of an online tablespace while the database is open. Note: You should not back up temporary tablespaces. Attempting to recover such a backup is risky and can return errors that result in inconsistent data.

For example, the attempted recovery operation can issue a fuzzy file warning, and can lead to an inconsistent database that you cannot open. Caution: If you fail to take the tablespace out of backup mode, then Oracle Database continues to write copies of data blocks in this tablespace to the online redo logs, causing performance problems.

Also, you receive an ORA error if you try to shut down the database with the tablespaces still in backup mode. Backing Up Online Tablespaces in Parallel You can simultaneously create data file copies of multiple tablespaces requiring backups in backup mode. Backing Up Online Tablespaces Serially You can place all tablespaces requiring online backups in backup mode one at a time. To back up online tablespaces serially: Prepare a tablespace for online backup.

Back up the data files in the tablespace. Alternatively, you can take the following manual measures after the system fails with tablespaces in backup mode: Recover the database and avoid issuing END BACKUP statements altogether. To take tablespaces out of backup mode simultaneously: Mount but do not open the database. Making User-Managed Backups of Read-Only Tablespaces When backing up an online read-only tablespace, you can simply back up the online data files.

Note: When restoring a backup of a read-only tablespace, take the tablespace offline, restore the data files, then bring the tablespace online. To back up the control file after a structural change: Make the desired change to the database. To back up the control file to a trace file: Mount or open the database. Making User-Managed Backups of Archived Redo Logs To save disk space in your primary archiving location, you may want to back up archived logs to tape or to an alternative disk location.

Making Backups in a Suspended Database After a successful database suspension, you can back up the database to disk or break the mirrors. Table Aspects of the Database Important for dd Usage Data Explanation Block size You can specify the size of the buffer that dd uses to copy data. Raw offset On some systems, the beginning of the file on the raw device is reserved for use by the operating system. Size of Oracle Database block 0 At the beginning of every Oracle database file, the operating system-specific code places an Oracle block called block 0.

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Some RAID devices benefit from suspending writes while the split operation is occurring; your RAID vendor can advise you on whether your system would benefit from this feature. After a successful database suspension, you can back up the database to disk or break the mirrors.

You must use conventional user-managed backup methods to back up split mirrors. RMAN cannot make database backups or copies because these operations require reading the datafile headers. Backing up a suspended database without splitting mirrors can cause an extended database outage because the database is inaccessible during this time. If backups are taken by splitting mirrors, however, then the outage is nominal.

The outage time depends on the size of cache to flush, the number of datafiles, and the time required to break the mirror. In a RAC configuration, you should not start a new instance while the original nodes are suspended. This prevents media recovery or crash recovery from hanging. Place the database tablespaces in backup mode.

For example, to place tablespace users in backup mode enter:. If your mirror system has problems with splitting a mirror while disk writes are occurring, then suspend the database. For example, issue the following:.

To pause or resume a database mirroring session use the Database Properties Mirroring page. During a database mirroring session, connect to the principal server instance, in Object Explorer, click the server name to expand the server tree. Right-click the database, select Tasks , and then click Mirror. This opens the Mirroring page of the Database Properties dialog box. A prompt asks for confirmation; if you click Yes , the session is paused, and the button changes to Resume.

On the primary database, take precautions to avoid a full transaction log. At this point, failover becomes possible. If the witness is present and ON, automatic failover is possible. In the absence of a witness, manual failover is possible. Feedback will be sent to Microsoft: By pressing the submit button, your feedback will be used to improve Microsoft products and services. Privacy policy.

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Cell phones while driving essays December 16, - am UTC. DBWR -- flushing blocks. All rights reserved. What is an acceptable period of time between the suspend and the resume command? The redo logs contain all changes required to recover the data files and make them consistent. And of course, keep up to date with AskTOM via the official twitter account. Some RAID devices benefit from suspending writes while the split operation is occurring; your RAID vendor can advise you on whether your system writing research proposal outline benefit from this feature.
Essay on tawheed Nystel, December 15, - pm UTC. Back up the data files in the tablespace. Taking tablespace Index offline while leaving tablespace Primary online can cause errors when data manipulation language DML is issued against the indexed tables located in Primary. You must use conventional user-managed backup methods to back up split mirrors. For example, enter:.
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For example, to put tablespace users in backup mode enter the following:. Archive the unarchived redo logs so that the redo required to recover the tablespace backups is archived. The following situations can cause a tablespace backup to fail and be incomplete:. Whenever recovery from a failure is required, if a data file is in backup mode when an attempt is made to open it, then the database does not open the data file until either a recovery command is issued, or the data file is taken out of backup mode.

In high availability situations, and in situations when no database administrator DBA is monitoring the database, the requirement for user intervention is intolerable. Hence, you can write a failure recovery script that does the following:. One node fails in a cold failover cluster that is, a cluster that is not an Oracle RAC configuration in which the secondary node must mount and recover the database when the first node fails. Alternatively, you can take the following manual measures after the system fails with tablespaces in backup mode:.

The primary purpose of this command is to allow a crash recovery script to restart a failed system without DBA intervention. You can also perform the following procedure manually. You can use this statement only when the database is mounted but not open. This method is useful when you are not sure whether someone has restored a backup, because if someone has indeed restored a backup, then the RECOVER command brings the backup up-to-date.

When backing up an online read-only tablespace, you can simply back up the online data files. You do not have to place the tablespace in backup mode because the database is not permitting changes to the data files. If the set of read-only tablespaces is self-contained, then in addition to backing up the tablespaces with operating system commands, you can also export the tablespace metadata with the transportable tablespace functionality.

If a media error or a user error occurs such as accidentally dropping a table in the read-only tablespace , you can transport the tablespace back into the database. To back up online read-only tablespaces in an open database:. For example, run this query:. For example, assume that you want to back up the history tablespace:.

Back up the online data files of the read-only tablespace with operating system commands. You do not have to take the tablespace offline or put the tablespace in backup mode because users are automatically prevented from making changes to the read-only tablespace. Optionally, export the metadata in the read-only tablespace. By using the transportable tablespace feature, you can quickly restore the data files and import the metadata in case of media failure or user error.

For example, export the metadata for tablespace history as follows:. The primary method for backing up the control file is to use a SQL statement to generate a binary file. A binary backup is preferable to a trace file backup because it contains additional information such as the archived log history, offline range for read-only and offline tablespaces, and backup sets and copies if you use RMAN. Back up the database's control file, specifying a file name for the output binary file.

You can edit the trace file to create a script that creates a new control file based on the control file that was current when you created the trace file. See Oracle Database Administrator's Guide to learn how to locate the alert log. To save disk space in your primary archiving location, you may want to back up archived logs to tape or to an alternative disk location. If you archive to multiple locations, then only back up one copy of each log sequence number. For example, run the following query:.

Back up one copy of each log sequence number by using an operating system utility. This example backs up all logs in the primary archiving location to a disk devoted to log backups:. Some third-party tools allow you to mirror a set of disks or logical devices, that is, maintain an exact duplicate of the primary data in another location, and then split the mirror. Splitting the mirror involves separating the copies so that you can use them independently.

Some RAID devices benefit from suspending writes while the split operation is occurring; your RAID vendor can advise you on whether your system would benefit from this feature. After a successful database suspension, you can back up the database to disk or break the mirrors.

You must use conventional user-managed backup methods to back up split mirrors. RMAN cannot make database backups or copies because these operations require reading the data file headers. Backing up a suspended database without splitting mirrors can cause an extended database outage because the database is inaccessible during this time.

If backups are taken by splitting mirrors, however, then the outage is nominal. The outage time depends on the size of cache to flush, the number of data files, and the time required to break the mirror. In an Oracle RAC configuration, you should not start a new instance while the original nodes are suspended. This prevents media recovery or failure recovery from getting into a unresponsive state.

Place the database tablespaces in backup mode. For example, to place tablespace users in backup mode, enter:. If your mirror system has problems with splitting a mirror while disk writes are occurring, then suspend the database. For example, issue the following statement:.

End the database suspension. Take the specified tablespaces out of backup mode. For example, enter the following statement to take tablespace users out of backup mode:. A raw device is a disk or partition that does not have a file system. A raw device can contain only a single file. Backing up files on raw devices poses operating system specific issues. The dd command on Linux and UNIX is the most common backup utility for backing up to or from raw devices.

See your operating system-specific documentation for complete details about this utility. Using dd effectively requires that you specify the correct options, based on your database. Table lists details about your database that affect the options you use for dd. Table Aspects of the Database Important for dd Usage.

You can specify the size of the buffer that dd uses to copy data. For example, you can specify that dd should copy data in units of 8 KB or 64 KB. The block size for dd need not correspond to either the Oracle block size or the operating system block size: it is the size of the buffer used by dd when making the copy. On some systems, the beginning of the file on the raw device is reserved for use by the operating system.

This storage space is called the raw offset. Oracle should not back up or restore these bytes. At the beginning of every Oracle database file, the operating system-specific code places an Oracle block called block 0. The generic Oracle code does not recognize this block, but the block is included in the size of the file on the operating system.

Typically, this block is the same size as the other Oracle blocks in the file. The information in Table enables you to set the dd options specified in Table Table Options for dd Command. The number of dd buffers to skip on the input raw device if a raw offset exists. The number of dd buffers to skip on the output raw device if a raw offset exists. The number of blocks on the input raw device for dd to copy. It is best to specify the exact number of blocks to copy when copying from a raw device to a file system; otherwise extra space at the end of the raw volume that is not used by the Oracle data file is copied to the file system.

Remember to include block 0 in the total size of the input file. Because a raw device can be the input or output device for a backup, you have four possible scenarios for the backup. The possible options for dd depend on which scenario you choose, as illustrated in Table Table Scenarios Involving dd Backups.

You set the dd block size to 8 KB when a raw device is involved in the copy. Like Linux and UNIX, Windows supports raw disk partitions in which the database can store data files, online logs, and control files. Each raw partition is assigned either a drive letter or physical drive number and does not contain a file system. On Windows, raw data file names are formatted as follows:. The procedure for making user-managed backups of raw data files is basically the same as for copying files on a Windows file system, except that you should use the Oracle OCOPY utility rather than the Windows-supplied copy.

Sample output follows:. Splits the input file into multiple output files. This option is useful for backing up to devices that are smaller than the input file. Combines multiple input files and writes to a single output file. This option is useful for restoring backups created with the -b option. To back up the data file onto drive E: , you can execute the following command at the Windows prompt after placing data file 7 in backup mode:. When drive E: fills up, you can use another disk. In this way, you can divide the backup of data file 7 into multiple files.

Similarly, to restore the backup, take the tablespace containing data file 7 offline and run this command:. You can use these applications to create snapshots of database files managed by the Oracle instance. December 16, - pm UTC. LGWR -- flushes redo from your update after a bit CKPT -- signalled by end of checkpoint to update datafile headers SMON wakes up and coalesces free space, generating log, dirty blocks and eventually causing a checkpoint.

SMON does tons in the background -- all of the time. Datafiles are constantly being written to, even when "nothing is happening". Nystel, December 16, - pm UTC. If there is no database activity then what information is being written into the control files every three seconds?

If the redo log buffers are not written to since database is not active , then what is the reason to flush the redo log buffers? Does that mean when there is no db activity still we will see online redo log file switched at the same frequency since redo log buffers gets flushed to online redo log files? December 17, - am UTC. SMON is doing stuff. SMON is generating redo. SMON is just one of them, SNPn's, intermedia, AQ, many other background processes out there with the potential to do stuff redo logs will only switch as they fill -- smon may eventually fill one and switch it sure.

Tom, When the database was put into suspend mode alter system suspend; then any kind of activities being happened to redo logs and control files?? Alter tablespace user begin backup; 2. Alter system suspend; 3. January 21, - pm UTC. The only way to get "consistent" and here consistent is not a goal, not a "good" thing is a cold backup after a normal or immediate shutdown. Those are normal good, desirable fuzzy hot backups. A reader, September 16, - pm UTC. Sorry I think I misplaced the link.

Hey Tom, 1. Can you please explain how three way mirrors work, in essence how is the database consistency achieved? Also: 2. On idle db: We had a simple test, we had a dummy database rnning for three days, doing nothing, it was just there, no queries, no dml nothing whatsoever.

Was curios, if something being written to, I thought our backup shouldn't have worked at all! Please help! Really appreciate your inputs. September 02, - am UTC. We do it by simply maintaining 1 or 2 copies mirror or triple mirror of extents on different failure groups. My question is regarding backgroung processes.

Thanks in advance. September 24, - am UTC. What is an acceptable period of time between the suspend and the resume command?