Creation of a deduplication database partition on a Linux MediaAgent fails

When you try to create a deduplication database (DDB) partition on a Linux MediaAgent, the operation fails because there is not enough space for the partition.

Symptoms

One of the following error messages appears in the Command Center or the CommCell Console:

• DDB disk is not configured properly.
• The path needs to be a logical volume(LVM) to perform DDB backup.
• Failed to check if the path is a logical volume(LVM) for DDB backup.

Causes

A DDB backup job uses LVM snapshots internally and requires that the partition be hosted on a logical volume with the following amount of available space: 10% of volume space as Copy-On-Write (COW) space and the amount of available COW space must be 4–49 GB.

• If 10% of the volume space is less than 4 GB, then the software will use 4 GB as COW space.
• If 10% of the volume space is more than 50 GB, then the software will use 50 GB as COW space.

This percentage also includes any space requirement specified by your hardware vendor. However, the snapshot of the DDB that is hosted on a thin logical volume grows dynamically and shares space from the thin pool if the amount of required space is not available.

Resolution

Verify that the path where you plan to create the DDB partition has the required amount of available space. To create a logical volume on a Linux MediaAgent, complete the following steps:

1. Create a volume group with the DDB disks using logical volume manager (LVM).
2. Create a logical volume from the volume group using up to 90% of the total disk space or meeting the space requirements described above.
3. Mount the logical volume.
4. Create the DDB partition within the mount point.