Free EMC D-PWF-DS-23 Practice Exam with Questions & Answers | Set: 2

The cause of the snapshot creation failure when a volume has a snapshot policy assigned is likely because the snapshot is the 61st created by the policy. According to Dell PowerFlex documentation, of the 126 user-available snapshots per volume, sixty (60) can be used for policy-based snapshot scheduling1. This means that if the policy attempts to create a snapshot beyond this limit, it will fail.

Here’s a step-by-step explanation of the issue:

• Snapshot Policy Limit: Each volume in a PowerFlex system can have a maximum of 126 user-available snapshots. For policy-based snapshot scheduling, the limit is 60 snapshots per volume1.
• Policy-Based Snapshot Creation: When a snapshot policy is in place, it will automatically attempt to create snapshots based on the defined schedule and retention levels.
• Failure Point: If the snapshot policy tries to create a snapshot and it is the 61st snapshot for that volume, the creation will fail because it exceeds the limit set for policy-based snapshots1.
• Resolution: To resolve this issue, the administrator would need to adjust the snapshot policy to ensure that it does not exceed the limit of 60 snapshots. This may involve modifying the retention levels or the frequency of snapshot creation.

This explanation is based on the snapshot policy details provided in the Dell PowerFlex documentation, which outlines the restrictions and uses of snapshots within the PowerFlex storage system1.

When migrating a vTree for a snapshot to a different storage pool in PowerFlex, one of the restrictions is that the migration cannot occur between storage pools with different data layouts if multiple volumes are involved in the vTree. This is because the data layout is fundamental to how data is organized and managed within the storage pool, and migrating multiple volumes with different data layouts could lead to inconsistencies and potential data integrity issues.

Here’s a more detailed explanation:

• Data Layout Compatibility: For a successful migration, the source and target storage pools should have compatible data layouts. Migrating vTrees that span multiple volumes between storage pools with different data layouts is restricted because it could disrupt the organization and accessibility of the data1.
• Single Volume Migration: While it is possible to migrate a single volume vTree between storage pools with different data layouts, doing so with multiple volumes in the vTree is not supported due to the complexity and risk involved1.

This restriction ensures that the integrity of the data is maintained during the migration process and that the storage system continues to operate reliably. It is important to consult the PowerFlex documentation, such as the “Configure and Customize Dell PowerFlex” guide, for detailed information on supported migration scenarios and restrictions1.