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Configuring a Subclient for Block-Level Backup

You can set up the block-level backup operations to meet your requirements.

Before You Begin

  • For Linux LVM snaps, there must be adequate free space in the LVM volume group for snapshot creation. The default COW cache size is set to 4096 MB or 10% of the volume size, whichever is greater. To increase the COW cache size, configure the nSnapCowSizeMB additional setting. For instructions on adding the additional setting, see Adding or Modifying Additional Settings from the CommCell Console.
  • For CVBF snaps, the COW files are created in the software_install_path/CVBF/cache directory by default. Over time, the COW files can grow significantly and fill up the volume. To move the COW files to another volume, configure the sCVBFSNAPPART additional setting. For instructions on adding the additional setting, see Adding or Modifying Additional Settings from the CommCell Console.
  • For AIX, verify that the minimum requirements specified in System Requirements are satisfied.
  • For Solaris ZFS file system, you must add all ZFS mount points that belong to the same zpool to one subclient. Block-level backups are not supported with metadata collection enabled.
  • Block-level backups cannot be run on root file system. 1-Touch and block-level backup features cannot be enabled on a subclient at the same time.

Procedure

  1. From the CommCell Browser, expand Client> File System.
  2. Right-click the backup set, point to All Tasks, and then click New Subclient.

    The Subclient Properties dialog box appears.

  3. On the General tab, in the Subclient name box, enter the subclient name.
  4. To set the content for the subclient, on the Content tab, click Browse to locate the content, and then click OK.

    Only a mount point can be configured as subclient content.

    Note: NFS and UNC paths are not supported.

  5. On the Storage Device tab, select the storage policy that you created.
  6. Click Advanced.
  7. On the Advanced Subclient Properties dialog box, click the Advanced Options tab.
  8. On the Advanced Options tab, set up your block-level backup:
    1. To enable block-level backup, select the Optimized for File system with large number of small files(Block Level Backup) check box.

      By default, block-level backup operations are catalog-free operations. This means that the file-level metadata is not collected during the scan phase of the snapshot job, thereby speeding up the scan phase. Depending on the number of files or folders present on the volume, the cataloging operation might be resource intensive. Hence, skipping the catalog operation during backup jobs results in faster backups.

      When you perform a browse operation to restore your backed up data, a live browse operation is initiated. This option is recommended for block-level backup operations.

    2. To perform file-level browse faster, select the Create File level Index during backup check box .

      Note: This option is not supported on Solaris.

      Backups may take longer when you enable this option because the scan phase might take time with large number of files or folders present on the volume. Hence, this option is not recommended for block-level backup operations.

      When you perform a browse operation to restore your backed up data, a browse operation from the index (generated from file-level cataloging) is initiated which is generally faster than a live browse operation.

      A browse operation from the index does not affect restore operations. The performance of file-level or volume-level restore operations is same with or without the Create File level Index during backup option enabled.

  9. Select additional options as appropriate for subclient creation and click OK.

Last modified: 10/9/2018 6:00:05 AM