Backup - Image Level

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Overview

Supported Backup Types

Image Level Backup Jobs

Configuring Multiple Streams for Backups

Enhancing Backup Performance on AIX Clients

Disabling Raw Device Backups on AIX Clients

Backup Considerations

Advanced Backup Options


Overview

Plan your backup jobs for this agent by reviewing the following information:


Supported Backup Types

This agent supports the following backup types:


Image Level Backup Jobs

This agent has the following unique functionality and options for protecting data:

The Image Level iDataAgent backs up the blocks of complete volumes, and restores them using Volume Level Restore or File Level Restore. Each backup for the iDataAgent on a Unix platform is either a CXBF backup or a non-CXBF backup.

CXBF Backups

CXBF backups are run on Unix platforms for this agent. To run a CXBF backup, QSnap must be installed on the client and you must configure a CXBF subclient. For more information, see Subclients - SAN iDataAgents. For a step-by-step procedure, see Run a CXBF Backup (Image Level/Image Level ProxyHost).

Non-CXBF Backups

Non-CXBF (Checksum) backups are run on Unix platforms for this agent. To run a non-CXBF (Checksum) backup, you must configure a non-CXBF (Checksum) subclient and also provide a supported snapshot. For more information, see Subclients - SAN iDataAgents. For a step-by-step procedure, see Run a non-CXBF Backup (Image Level/Image Level ProxyHost).

Backing up Application Data

To facilitate the backup of data files for application such as Exchange and SQL, PreScan and PostScan commands can be utilized to quiesce and unquiesce the application during the backup. For more information, see Pre/Post process commands.

Oracle BLI

To be able to back up Oracle instances with the Image Level iDataAgent, the Oracle data files and Oracle archive logs must reside on two separate volumes. In addition, the Oracle installation binaries, control file, and online redo logs must reside in volumes other than the data files volume and the archive logs volume.

During an Oracle backup, each Image Level subclient is expected to quiesce one instance at a time. Do not configure an Image Level subclient's content with more than one Oracle instance; create separate subclients for each Oracle instance.

Pre/Post process commands are required to quiesce and unquiesce the Oracle instance during the backup. See the Agent-Specific Guidelines for more information.

For step-by-step instructions, see Back up Oracle Instances with the Image Level iDataAgent.


Configuring Multiple Streams for Backups

Multi-Streaming employs multiple data streams per subclient for data protection operations. This enables the subclient's contents to be distributed to all the streams, transmitting them in parallel to the storage media. Hence a subclient whose data is secured using three data streams, utilizes more of the available network resources, and can complete in as little as one third the time that the same data would require using a single stream.

Note that, you do not have to enable multi-streaming if you have multiple mount points pointing to the same physical drive.

For Unix, multiple streams are supported for CXBF backups. Follow the steps given below to configure multi-streaming.

  1. From the CommCell Browser, navigate to Client Computers | <Client> | Image Level on Unix.
  2. Right-click the <Subclient> in the right pane and then click Properties.
  3. Click CXBF.
  4. In the Number of Data Readers box type or select the number of data streams.
  5. Select the Allow multiple data readers within a drive or mount point check box.
  6. Click the Storage Device tab.
  7. In the Storage Policy list, click a storage policy name.
  8. Click OK.
  The number of streams configured in the Storage Policy should be equal to, or greater than the specified Number of Data Readers .

 

Enhancing Backup Performance on AIX Clients

Image level backup performance on AIX clients can be increased by increasing the amount of data read (chunk size) in one attempt during backups. By default, the chunk size is 4096 Bytes. For a typical read size of 61440 Bytes, it will take 15 data read iterations to complete the data fetch. If the chunk size is increased to 65536 Bytes, only one data read iteration is needed.

Increasing the Data Read Size

Use the following steps to increase the amount of data read (chunk size) in one attempt:

  1. From the CommCell Console, navigate to Client Computers.
  2. Right-click the <Client>, and then click Properties.
  3. Click the Registry Key Settings tab.
  4. Click Add.
  5. In the Name field, type dSnapChunkSize.
  6. In the Location list, type UnixImageIDA.
  7. In the Type list, select Value.
  8. In the Value field, type 65536.
  9. Click OK.

Enabling Data Classification for Metadata Collection

Metadata contains information such as the directory structure and file attributes. Metadata collection at the file level during backups is necessary to perform file level restores. Metadata collection performance can be enhanced using Data Classification. When Data Classification is used for metadata collection, ACLs will not be available for restore

On a Unix platform, a CXBF device is a volume or partition that is monitored by the CXBF block-filter driver. Consider the following when configuring a CXBF device:

  1. Ensure that the Data Classification database is located on a non Data Classification monitored volume and a non CXBF monitored volume.
  2. At the Unix prompt on the client computer, type the command to define the location of the Data Classification database after navigating to the /opt/Simpana/Base location:

    DcClient -edit DB_FOLDER <dbpath>

    The <dbpath> must exist prior to running the command.

  3. From the CommCell Browser, navigate to Client Computers | <Client> | Image Level on Unix.
  4. Right-click the <Subclient> and click Properties.
  5. Click Volume Explorer, and then click Yes on the warning dialog box.
  6. Select the host connected to the volume you want to configure, and then right-click the volume and select Configure CXBF device.
  7. Click Configure in the Submit Configure Request dialog box.
  8. Click OK.
  9. At the Unix prompt on the client computer, type the command to start monitoring the CXBF mount point after navigating to the /opt/Simpana/Base location:

    DcClient -monitor <mount path>

    where: <mount path> is the CXBF mount point that you want to add to the monitoring list.

  10. From the CommCell Console, navigate to Client Computers.
  11. Right-click the <Client>, and then click Properties.
  12. Click the Registry Key Settings tab.
  13. Click Add.
  14. In the Name field, type sUseDCForMetaData.
  15. In the Location list, type UnixImageIDA.
  16. Click OK.

Disabling Raw Device Backups on AIX Clients

Raw device backups are enabled by default on AIX clients. However, you can disable raw device backups and allow block device based backups using the following steps:

  1. From the CommCell Console, navigate to Client Computers.
  2. Right-click the <Client>, and then click Properties.
  3. Click the Registry Key Settings tab.
  4. Click Add.
  5. In the Name field, type sSnapUseBlkDevice.
  6. In the Location list, type UnixImageIDA.
  7. In the Type list, select Value.
  8. In the Value field, type Y.
  9. Click OK.

Backup Considerations

Before performing any backup procedures for this agent, review the following information:

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