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 4096 MB which might be insufficient for large volumes. You must set it to 10% of the volume size to avoid snapshot failures. To increase the COW cache size, configure the nSnapCowSizeMB additional setting. For instructions on adding the additional setting, see Add or Modify an Additional Setting.
  • 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 Add or Modify an Additional Setting.
  • For AIX, verify that the minimum requirements specified in System Requirements are satisfied. Otherwise, use QSnap for block-level backups. For instructions on how to install QSnap, see Deployment - QSnap for UNIX File System. To back up volumes with QSnap, you must configure the volumes as CXBF devices. For more information, see Configuring CXBF Devices using Volume Explorer.

Procedure

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

    The Subclient Properties dialog box appears.

  3. On the General tab, configure the subclient name and locked file settings:
    1. In the Subclient name box, enter the subclient name.
    2. For AIX, verify that the minimum requirements specified in System Requirements are satisfied. Otherwise, select the Use QSnap to handle backup of locked files check box.
  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.

  5. On the Storage Device tab, select the storage policy that you created.
  6. 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.
    2. To perform file-level browse faster, select the Create File level Index during backup check box .

      Backups may take longer when you enable this option depending on the data scan type selected.

      Scan Type Effect
      Recursive Scan A file scan is used to determine the modified data, resulting in a longer completion time.
      Optimized Scan A customized database that contains information about the files is used to quickly determine the modified data, resulting in a reduced snap backup duration.
  7. Select additional options as appropriate for subclient creation and click OK.

    The new subclient appears under defaultBackupSet node.