Dell EMC Dell PowerFlex Design 2023 D-PWF-DS-23 Exam Questions

Answer : C

In PowerFlex File shares, when a soft limit quota is exceeded, it triggers a grace period during which users can still write data to the share. The grace period is a predefined time frame that allows users to either reduce the amount of stored data or to adjust the quota settings. As long as the hard limit quota has not been reached, users can continue to write files to the share, even if the soft limit has been exceeded and the grace period is in effect1.

The soft limit is essentially a warning threshold that alerts users that they are approaching the maximum allowed capacity, but it does not immediately prevent new writes. The hard limit, on the other hand, is a strict limit that, once reached, will prevent any further writes to the share until the stored data is reduced below the hard limit or the quota is increased.

Since the question states that the number of files is still below the hard limit quota, the user will be able to write a new file to the share location. Therefore, the correct answer is C. The file is written as the hard limit has not been reached.

Answer : A

To maximize the storage capacity available to the system while utilizing NVDIMMs, SAS, and NVMe disks, the design should include both a Storage Pool and an Acceleration Pool. The Storage Pool will be used for the bulk storage provided by the SAS disks, while the Acceleration Pool, leveraging the high-speed NVMe disks, will be used to accelerate the performance of the storage system.

The use of NVDIMMs in PowerFlex is associated with enabling fine-granularity storage pools that provide compression, which is beneficial for space efficiency, especially with heavy snapshot use1. This configuration allows for the creation of a storage pool that can take advantage of the NVDIMMs' capabilities for compression and the high capacity of the SAS disks, while the NVMe disks in the Acceleration Pool provide high-performance storage for more demanding workloads.

Therefore, the correct answer is A. One Storage Pool and one Acceleration Pool, as this design will provide the highest capacity of storage available to the system while also ensuring optimal performance through the use of NVMe disks in the Acceleration Pool.

Answer : C

Before permanently removing a node that is the primary MDM from a PowerFlex system, it is crucial to ensure that the MDM roles are reconfigured to maintain cluster availability and avoid errors. This process involves promoting another node to take over the primary MDM role and ensuring that the cluster continues to function correctly without the node that is being removed.

The steps to reconfigure MDM roles using PowerFlex Manager are as follows:

Log in to PowerFlex Manager.

Navigate to the MDM cluster settings.

Identify a suitable node that can be promoted to the primary MDM role.

Use the PowerFlex Manager interface to promote the selected node to the primary MDM role.

Ensure that the cluster is stable and that the new primary MDM is functioning correctly.

Once the new primary MDM is in place and operational, the original primary MDM node can be safely removed from the cluster.

This process is essential to prevent any disruptions in the management and operation of the PowerFlex system. The other options listed, such as using the remove_standby_mdm SCLI command (Option A) or the switch_cluster_mode SCLI command (Option B), do not directly address the reconfiguration of MDM roles. Deactivating the Protection Domain (Option D) is not related to the removal of an MDM node and would not be a recommended step in this scenario.

Therefore, the correct answer is C. Use PowerFlex Manager to reconfigure MDM roles, as it ensures that the MDM responsibilities are transferred to another node before the primary MDM node is removed, thus maintaining the integrity and availability of the PowerFlex system1.

Answer : A

The creation of a NAS server requires a dedicated storage pool. If a storage pool specifically for NAS has not been created, the NAS server creation will fail. This is because the NAS server needs to allocate space from a storage pool to store the file system data. Without a designated storage pool, the NAS server cannot be configured properly1.

The other options, while important for the operation and integration of a NAS server, are not directly related to the creation process itself. For instance, using the same VLAN as block storage networks (Option B) may lead to network conflicts, but it would not prevent the creation of the NAS server. Similarly, not defining DNS in the NAS server creation wizard (Option C) could cause resolution issues later on, but it is not a prerequisite for the creation of the NAS server. Lastly, while adding FSN to the cluster (Option D) is a necessary step for enabling file system services, it is not the cause of the NAS server creation failure in this context.

Therefore, the correct answer is A. A Storage Pool for NAS has not been created, as it is a fundamental requirement for the NAS server creation process in a PowerFlex environment.

Answer : B, C

Placing an SDS into Protected Maintenance Mode (PMM) can fail due to several scenarios, two of which are:

Another node in the same protection domain is in maintenance mode: PMM is designed to ensure data protection and availability during maintenance activities. If another node within the same protection domain is already in maintenance mode, initiating PMM on an additional node could compromise the protection domain's ability to maintain data availability and redundancy1.

Another node has failed in the same protection domain: The failure of a node within the same protection domain can prevent the initiation of PMM for another node. This is because the system needs to ensure that there is sufficient redundancy and that data protection is not jeopardized by having multiple nodes in a non-operational state within the same protection domain1.

These scenarios are based on the operational principles of PowerFlex's maintenance modes, as described in the Dell PowerFlex documentation. The system's priority is to maintain data protection and availability, and therefore, it restricts the ability to enter PMM under conditions that could threaten these objectives1.

Answer : C

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.

Answer : B

To calculate the required journal capacity, we need to consider the maximum cumulative writes that might occur during an outage. The calculation is based on the application's write bandwidth and the duration of the supported outage. For an application generating 2 GB/s of writes, using a 2-hour outage (which is 7200 seconds), the journal capacity reservation needed is:

JournalCapacity=WriteBandwidthOutageDuration

JournalCapacity=2GB/s7200s=14400GB

However, since the question specifies that the outage is under two hours, we use the minimum outage allowance of 1 hour for the calculation, which is 3600 seconds. Therefore, the correct calculation is:

JournalCapacity=2GB/s3600s=7200GB

But considering the recommendation to use three hours in the calculations for safety, the needed capacity would be approximately 10.547 TB, which is roughly 10.800 GB12. Hence, the verified answer is 10.800 GB.