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Optimized Scan - Frequently Asked Questions

Table of Contents

How does the Optimized Scan method enhance the scanning capabilities of an iDataAgent?

When you enable the Optimized Scan for a File System, a meta database is created. The meta database contains information about the files in the associated volume. This Optimized service constantly updates the databases to track file additions, volume additions, content update to files, etc. Journals from the File System Filter (FSF) driver are used to keep track of the updates to each meta database.

Why is Optimized Scan not running on the volume even after enabling it?

If the free space on the mounted volume falls below the minimum 1GB watermark, volume monitoring will be stopped.

Why is the .DATACLASS_nn directory not backed up when I back up a subclient with optimized scan enabled?

The .DATACLASS_nn directory contains the optimized scan meta data. By default, the .DATACLASS_nn directory is excluded from backups.

What is the default location of the meta database?

The default location of the meta database is as follows:

UNIX Windows

The meta database is located at the root of each mount point, and is named .db.cv.

For example: For /home, it would be /home/.DATACLASS_1/.db.cv

You can relocate the database to a centralized location.

On each volume, the metadata database is created at the following location:

System Volume Information\NetApp\Data Classification

It is named as dc_<instance_number>.db

For example: On the C drive, it would be C:\System Volume Information\NetApp\Data Classification\dc_<instance_number>.db

You cannot relocate the database.

How much hard disk space is consumed by the metadata database?

The meta databases created by Optimized Scan usually consume about 5% of the total space on the hard disk. Depending on the type of data and folder layout, the metafiles may consume additional space.

Each Optimized Scan update record consumes about 256 bytes (this assumes an average short name length of 16 bytes and an average full path length of 256 bytes).

When the volume where Optimized Scan database resides or the volume monitored by Optimized Scan gets full, free up some space or add more space to the volume. Manually delete the Optimized Scan database.

What is the procedure to change the location of the Optimized Scan cache directory?

During the File System iDataAgent installation, cvdccache directory is automatically created at the specified location. This directory contains the Optimized Scan cache. To change the Optimized Scan cache directory, use the following steps:

  1. Stop SnapProtect services on the client.
  2. From the CommCell Browser, expand Client Computers.
  3. Right-click the Client, and then click Properties.
  4. In the Client Computer Properties dialog box, click Advanced.
  5. In the Advanced Client Computer Properties dialog box, on the Additional Settings tab, click Add.
  6. In the Add Additional Settings on Unix Client dialog box, specify the path to the new location for the Optimized Scan cache:
    • In the Name box, type dCacheRootDir. The Category and Type fields are automatically populated.

      Alternatively, you can click Lookup and search for the additional setting using the Find box.

    • In the Value box, type the path to the new location for the Optimized Scan cache. The new path must contain the cvdccache directory.
    • Click OK.
  7. On the Additional Settings tab, click Add again.
  8. In the Add Additional Settings on Unix Client dialog box, specify the path to the new location for the Optimized Scan journal store:
    • In the Name box, type dRawBufferDir. The Category and Type fields are automatically populated.

      Alternatively, you can click Lookup and search for the additional setting using the Find box.

    • In the Value box, type the path to the new location for the Optimized Scan journal store. The new path must contain the cvdccache/RawBuffer directory.
    • Click OK.
  9. Click OK to close the Advanced Client Properties dialog box and the Client Computer Properties dialog box.

If you change the Job Results directory, you must manually update the new Job Results path for the dCacheRootDir and dRawBufferDir additional settings; otherwise, the Optimized Scan service will fail to initialize. For more information, see FAQ.

Optimized Scan and ContinuousDataReplicator use the same location for cache. If you have installed ContinuousDataReplicator, follow these steps to change the cache location for ContinuousDataReplicator:

  1. From the CommCell Browser, expand Client Computers.
  2. Right-click the Client, and then click Properties.
  3. In the Client Computer Properties dialog box, click Advanced.
  4. On the General tab, type the location of the new CDR log file in the CDR Log File Location box.
  5. Click OK.

Why is the Optimized Scan service failing whenever I change the Job Results path?

The Job Results directory stores the job results files that get created when a job is initiated. You need to manually update the new Job Results path for the dCacheRootDir and dRawBufferDir additional settings whenever you change the Job Results directory; otherwise, the Optimized Scan service fails to initialize.

For example, if you change the Job Results path from /opt/snapprotect/iDataAgent/jobResults/cvdccache to /JobResults, then configure the additional settings as follows:

  • dCacheRootDir /JobResults/cvdccache
  • dRawBufferDir /JobResults/cvdccache/RawBuffer

Why is my volume still monitored after disabling Optimized Scan from the CommCell Console?

Volumes that are added manually using the DcClient command will continue to be monitored even after you disable Optimized Scan from the CommCell Console. To disable monitoring for such volumes, run the following command.

./DcClient -donot-monitor /<mount_path>

Why is the disk space not released after deleting files?

If the deleted files belong to a file system that is monitored, the inodes of the recently used files are not freed up immediately. Disk space will show the corresponding size increase after 5 minutes of inactivity on the files.

What is the procedure to delete the Optimized Scan database on Windows?

The Optimized Scan database is available on every volume. If you have multiple volumes, perform the following steps to delete the database manually from each volume.

  1. Stop the services on the client machine.
  2. Download third-party PsExec tool.
  3. At the command prompt, type the following:

    psexec -i -s cmd

    This opens a new command prompt window.

  4. Delete the database dc_<instance_number>.db from its location. Usually, the database is available at the following location:

    System Volume Information\##_DOC_OEM_INSTALL_DESTINATION_COMPANY_FOLDER_## \Data Classification

    Enter the following in the new command prompt:

    C:\System Volume Information\##_DOC_OEM_INSTALL_DESTINATION_COMPANY_FOLDER_##\Data Classification>del dc_002.db

    where C:\ is the drive where the database is located and dc_002.db is the database to be deleted.

How do I turn off/on Optimized Scan for a volume on a Windows client?

Use the nStartDataClassifier additional setting to enable or disable the Optimized Scan services on a client computer as follows:
  1. From the CommCell Browser, navigate to Client Computers.
  2. Right-click the <Client> in which you want to add the additional setting, and then click Properties.
  3. In the Client Computer Properties dialog box, click Advanced.
  4. In the Advanced Client Properties dialog box, click the Additional Settings tab.
  5. Click Add.
  6. In the Add Additional Settings on Windows Client dialog box, the Name box, type nStartDataClassifier.

    The Category and Type details are automatically populated.

  7. In the Value box, type 1 to enable or 0 to disable the data classification monitoring for all the volumes.
  8. Click OK.

If you want to disable Optimized Scan for selected volumes, use the VolumeFilters additional setting to provide the list of volumes as follows:

  1. From the CommCell Browser, navigate to Client Computers.
  2. Right-click the <Client> in which you want to add the additional setting, and then click Properties.
  3. In the Client Computer Properties dialog box, click Advanced.
  4. In the Advanced Client Properties dialog box, click the Additional Settings tab.
  5. Click Add.
  1. In the Add Additional Settings on Windows Client dialog box, the Name box, type VolumeFilters.

    The Category and Type details are automatically populated.

  2. In the Value box, type Drive Letter for the volume that you want to filter.
  3. Click OK.