Nutanix NCP-MCI-6.5 Practice Test - Questions Answers, Page 7

The correct answer is D. VM Storage Controller Bandwidth.

VM Storage Controller Bandwidth is a metric that measures the amount of data that a VM is reading and writing to the storage fabric. The storage fabric is the network of storage controllers (CVMs) that provide distributed and fault-tolerant storage services to the VMs on the Nutanix cluster. The VM Storage Controller Bandwidth metric shows the read and write bandwidth in megabytes per second (MBps) for each VM. The higher the bandwidth, the more data the VM is transferring to and from the storage fabric1.

The administrator can use Prism Central to view the VM Storage Controller Bandwidth metric for each VM in a chart or a widget. The administrator can also use Prism Central to view other metrics related to the VM's storage performance, such as VM Storage Controller IOPS, VM Storage Controller Latency, and VM Disk Usage2.

Based on the VM performance metrics shown in the exhibit, the most likely cause of the poor performance in the particular VM is that the host's CPU is severely overloaded. This is indicated by the high percentage of Hypervisor CPU Ready Time, which is shown as 96% in the CPU ready chart. CPU Ready Time is a metric that shows the amount of time a VM is ready to run but is unable to run because the host CPU resources are not available. In a healthy environment, this value is typically low. A high percentage indicates that the VMs are waiting for available CPU cycles, which means the CPU is not able to schedule the VM effectively, often due to overcommitment or heavy CPU load.

When the CPU ready time is consistently high, it is a clear indicator that the VM is frequently waiting for CPU resources, which can lead to performance issues such as sluggishness or delays in processing. It is not related to the storage subsystem (Oplog fullness or SSD tier size), nor directly to the number of vCPUs assigned to the VM. While adding more vCPUs might seem like a solution, it could actually exacerbate the issue if the host is already CPU constrained.

To resolve this issue, an administrator should consider balancing the load across the hosts more effectively, possibly by using Nutanix's built-in automation and balancing features, or by scaling out the cluster to add more CPU resources. It is also advisable to check for any VMs with unusually high CPU demand and to adjust resource allocation as needed. Nutanix provides extensive documentation and guidelines in their Resource Management Guide to help administrators identify and resolve such performance issues.

According to the image description, the exhibit shows a screenshot of a computer screen with a table of data. The table has 6 columns and 4 rows. The columns are labeled ''Date'', ''Time'', ''Status'', ''Details'', ''Configuration'', and ''Duration''. The rows contain information about different configurations and their statuses. The background is a light blue color. There is a pop-up message on the bottom right corner of the screen that reads ''This question has been answered. Click here to enable the edit button.''

Based on the table data, it seems that the screenshot is taken from the Prism Central web console, showing the results of a cluster health check report.The report shows that there are four failed checks: Host Password Policy, CVM Password Policy, NTP Configuration, and Cluster Time Skew2. These checks indicate that some initial cluster configuration tasks were missed during the deployment process.

The Host Password Policy check verifies that the host passwords are not set to default values and are compliant with the password policy defined in Prism Central3.The CVM Password Policy check verifies that the CVM passwords are not set to default values and are compliant with the password policy defined in Prism Central4. These checks are important for ensuring the security and compliance of the cluster. Therefore, changing the host and CVM passwords from their default values and following the password policy guidelines are two initial cluster configuration tasks that were missed.

A managed network is a type of network that can be created on an AHV cluster and allows VMs to automatically be assigned an IP address at creation time. A managed network uses the Nutanix IP Address Management (IPAM) service, which provides DHCP and DNS functionality for the VMs on the network. A managed network can be configured with a subnet range, a default gateway, and DNS servers. The IPAM service will allocate IP addresses from the subnet range to the VMs and register their hostnames in the DNS servers.The IPAM service will also release the IP addresses when the VMs are deleted or moved to another network1.

To create a managed network on an AHV cluster, the administrator can use Prism Element or Prism Central.The steps are as follows2:

In Prism Element, go to the Network Configuration page and click Create Network.

In Prism Central, go to the Networks page and click Create.

Enter a name and description for the network.

Select Managed as the network type.

Enter the subnet range, default gateway, and DNS servers for the network.

Optionally, enable VLAN tagging and enter a VLAN ID for the network.

Click Save.

The cluster time zone is a setting that determines the time zone used by all CVMs in the cluster. The cluster time zone affects the timestamps of Nutanix logs, events, alerts, and reports. The cluster time zone also affects the scheduling of tasks such as snapshots, replication, and upgrades.By default, the cluster time zone is set to UTC (Coordinated Universal Time) when the cluster is created3.

To change the cluster time zone, the administrator needs to use the ncli (Nutanix command-line interface) on any CVM in the cluster.The steps are as follows4:

Log in to any CVM using SSH.

Runncli cluster get-timezoneto check the current cluster time zone.

Runncli cluster set-timezone timezone=<timezone>to change the cluster time zone, where<timezone>is a valid time zone identifier (for example, America/New_York).

Runncli cluster get-timezoneagain to verify that the cluster time zone has been changed.

Note that changing the cluster time zone does not affect the time zone of Prism Element or Prism Central VMs.To change their time zone, the administrator needs to use Prism Element UI or Prism Central UI respectively5.

Stargate is the AOS process that handles all I/O operations for the cluster. It is responsible for determining whether an I/O from a user will be written to the OpLog or to the Extent Store, based on the type and size of the I/O.Stargate also performs data tiering, compression, deduplication, and erasure coding1.Stargate runs on every CVM and communicates with other Stargates to ensure data locality and redundancy2.

One of the possible reasons for a cluster to transition out of NearSync is insufficient network bandwidth between the source and target clusters.NearSync requires a minimum network bandwidth of 10 Mbps per VM for replication3. If the network bandwidth is lower than the required amount, the replication of recovery points may take longer than the configured RPO, resulting in an Out of NearSync condition.To address this issue, you can increase the network bandwidth between the clusters or reduce the number of VMs protected by NearSync4.

The correct answer is A. Long term storage of data which is written once and read infrequently.

Erasure Coding is a feature that increases the usable capacity on a Nutanix cluster by reducing the amount of data replication. Instead of replicating data, Erasure Coding uses parity information to rebuild data in the event of a disk failure. The capacity savings of Erasure Coding is in addition to deduplication and compression savings1.

Erasure Coding is most beneficial for scenarios where the data is written once and read infrequently, such as long term storage of archival data, backup data, or cold data. This is because Erasure Coding has some trade-offs and limitations that may affect the performance and availability of the cluster. Some of these trade-offs and limitations are2:

Erasure Coding requires more CPU and memory resources than replication, as it involves more complex calculations for encoding and decoding data.

Erasure Coding increases the network bandwidth consumption, as it involves more data transfers between nodes for encoding and decoding data.

Erasure Coding reduces the resiliency of the cluster, as it can tolerate fewer node failures than replication. For example, a cluster with redundancy factor 2 can tolerate one node failure with replication, but only two disk failures with Erasure Coding.

Erasure Coding is not effective for workloads that have many overwrites or random writes, as it involves more overhead for updating the parity information.

Erasure Coding is not supported for some features, such as volume groups, file server VMs, or Metro Availability.

Therefore, if an administrator needs to configure a container on a Nutanix cluster, they should enable Erasure Coding only if the container will store data that is written once and read infrequently. This way, they can maximize the capacity savings of Erasure Coding without compromising the performance and availability of the cluster.

LCM (Life Cycle Manager) is a feature that allows Nutanix administrators to perform one-click firmware and software upgrades for Nutanix clusters and components. LCM fetches inventory and update information from a pre-configured URL that contains the latest versions of firmware and software packages. However, upgrading Nutanix AOS does not automatically update the fetch URL. To update the fetch URL, the administrator needs to update the LCM framework.The LCM framework is the core component of LCM that provides the logic and functionality for inventory, download, and upgrade operations1.

To upgrade the LCM framework, the administrator needs to perform an LCM inventory. An LCM inventory is a process that scans the cluster and its components for their current firmware and software versions and compares them with the available versions from the fetch URL. If there is a newer version of the LCM framework available, it will be shown as an update option under Cluster Software Component in the Available Updates page.The administrator can then select and apply the LCM framework update to upgrade it to the latest version2.

The administrator can perform an LCM inventory using Prism Element or Prism Central.The steps are as follows3:

In Prism Element, go to the Network Configuration page and click Life Cycle Management.

In Prism Central, go to the Services page and click Life Cycle Management.

Click Inventory in the toolbar and select Perform Inventory from the drop-down menu.

Wait for the inventory process to complete and check for any available updates.