NS0-593 NetApp Certified Support Engineer ONTAP Specialist Questions and Answers

According to the SAS cabling rules and concepts for shelves with IOM12/IOM12B modules1, one of the goals is to provide a single, easily understood universal algorithm for all SAS products and configurations. One of the rules is that of the two paths to a single disk storage stack from a single node, one should connect to the top and one to the bottom of the storage stack. This ensures maximum possible resilience and minimizes the reliance on controller takeovers. The exhibit shows that both SAS connections from one controller go to the same shelf, which violates this rule and causes the error message. This situation is not normal for a FAS2750 single-node system and can reduce reliability and availability. The cables should be reconnected according to the SAS cabling rules and the controller-to-stack cabling worksheet template for quad-pathed connectivity2. References = SAS cabling rules and concepts - shelves with IOM12/IOM12B modules, SAS cabling issue: Both SAS connections from one controller go to the same shelf, Controller-to-stack cabling worksheet template for quad-pathed connectivity.

= The “Urge” column in the flexgroup show command indicates the urgency of data rebalancing for each constituent volume. A non-zero value means that the data placement is uneven across the volumes, which can affect the performance of the FlexGroup. The target value is the desired percentage of data for each volume, and the difference value is the deviation from the target. The FlexGroup tries to balance the data placement by moving data between the volumes, but this process can be slow or interrupted by other factors. Therefore, it is recommended to monitor the “Urge” column and take corrective actions if the values are high orpersistent. References = What do “flexgroup show” target and urgency and other columns mean?, NetApp ONTAP FlexGroup volumes — Best practices and implementation guide

= AutoSupport is enabled by default for Cloud Manager and ONTAP Cloud systems. It proactively monitors the health of your systems and sends messages to NetApp technical support. To enable AutoSupport, you must provide your NetApp Support site credentials to Cloud Manager. If your credentials are incorrect or expired, Cloud Manager will not be able to send AutoSupport messages to NetApp. Therefore, the solution for this issue is to verify that your NetApp Support site credentials are correctly added to Cloud Manager. References = Troubleshooting Cloud Manager and ONTAP Cloud, Set up AutoSupport

 = The Connector is a software component that enables Cloud Manager to manage resources and processes within your AWS environment. To deploy a Connector in AWS, you need to have the correct IAM policies attached to your user account or role. These policies grant the Connector the permissions to perform various actions on your behalf, such as creating and deleting EC2 instances, VPCs, security groups, and so on. If you do not have the required IAM policies, the deployment will fail with the message ‘Insufficient permissions to deploy Cloud Connector’. You can find the list of required IAM policies in the Connector deployment policy for AWS. References = Creating a Connector in AWS from Cloud Manager, page 3-4.

• A speed mismatch occurs when the cluster ports on different nodes have different speeds, such as 10 Gbps and 40 Gbps1.
• A speed mismatch can cause packet loss, retransmits, and latency on the cluster network, especially when data is accessed indirectly, meaning that the node serving the data is different from the node hosting the LIF2.
• In this scenario, the AFF A300 nodes have 10 Gbps cluster ports, while the AFF A700 nodes have 40 Gbps cluster ports, creating a speed mismatch on the cluster interconnect34.
• The Cisco Nexus 3132Q cluster interconnect switches support both 10 Gbps and 40 Gbps cluster ports, but they have a shallow buffer size of 9 MB per port, which can be easily overwhelmed by the bursty traffic generated by the speed mismatch.
• To solve this problem, you need to either upgrade the cluster ports on the AFF A300 nodes to 40 Gbps, or downgrade the cluster ports on the AFF A700 nodes to 10 Gbps, to achieve a homogeneous cluster interconnect1.
• Alternatively, you can use QoS policies to limit the bandwidth of the cluster ports to avoid oversubscription and congestion on the cluster interconnect. References:
• 1: Cluster network cabling, ONTAP 9 Documentation Center
• 2: Cluster Network Latency - Troubleshooting Guide, NetApp Knowledge Base
• 3: AFF A300 Tech Specs, NetApp
• 4: AFF A700 Tech Specs, NetApp
• [5]: Why do network speed mismatches create problems with shallow buffered switches?, NetApp Knowledge Base
• [6]: How to use QoS to limit the bandwidth of cluster ports, NetApp Knowledge Base

 Updating the Vscan servers one at a time can prevent the clients from losing access to the files on the CIFS SVM, as there will always be at least one Vscan server available for scanning. Disabling the -scan-mandatory flag in the Vscan policy can also avoid the issue, as it allows the clients to access the files even if there are no Vscan servers online, but this may compromise the security of the data. Enabling the -scan-mandatory flag or modifying the CIFS shares to be CA shares will not help, as they do not affect the availability of the Vscan servers or the scanning process. References = Vscan server installation and configuration, Update the Vscan On-Access policy configuration for an SVM

The maxdirsize is the maximum size of a directory in a FlexVol or FlexGroup volume. It is determined by the number of inodes allocated to the directory. If the directory contains more files than the maxdirsize can accommodate, then the ONTAP software will return an out of space error message to the host, even if the volume has enough free space. This can happen when a FlexGroup volume has a flat directory structure with millions of files, as the maxdirsize is not automatically adjusted for FlexGroup volumes12. References: 1: FlexGroup volumes: Frequentlyasked questions | NetApp Documentation 2: How to increase the maxdirsize of a FlexVol volume - NetApp Knowledge Base

 If both root aggregates are destroyed in a two-node cluster, the cluster will be inoperable and the data will be inaccessible. To recover from this situation, you need to perform the following actions:

• Install ONTAP from a USB device on one of the nodes. This will create a new root aggregate and a new cluster on that node.
• Rejoin the second node to the re-created cluster. This will also create a new root aggregate on the second node and synchronize it with the first node.
• Restore the cluster configuration and data from a backup, if available. References =
• ONTAP 9 Documentation Center
• Storage System Recovery Troubleshooting
• Recovering from a root aggregate failure

 To enable DDNS updates to work, two actions should be performed:

• Remove the NFS protocol from the cifs_01 data LIF. This is because DDNS updates are only supported for LIFs that have only one data protocol enabled1. The cifs_01 LIF has both NFS and CIFS protocols enabled, which prevents it from registering its DNS record dynamically. By removing the NFS protocol from the cifs_01 LIF, it will become eligible for DDNS updates.
• Enable the -is-enabled parameter for the SVM DDNS services. This is because the -is-enabled parameter controls whether the SVM sends DDNS updates to the DNS servers2. The exhibit shows that the -is-enabled parameter is set to false for the svm1 SVM, which means that it does not send any DDNS updates. By enabling the -is-enabled parameter, the SVM will start sending DDNS updates for its eligible LIFs. References:
• 1: Configure dynamic DNS services3
• 2: Manage DNS/DDNS services with System Manager4

= CPU utilization in ONTAP is not a linear measure of the system load, nor can it be used alone as a measure of the overall system utilization. ONTAP uses a Coarse Symmetric Multiprocessing (CSMP) design which partitions system functions into logical processing domains, each with its own scheduling rules and resource availability. Therefore, a high CPU utilization does not necessarily indicate a performance problem, unless it is accompanied by other contributing factors such as high latency, low throughput, or high queue depth. ONTAP has several mechanisms to optimize CPU usage and balance the workload across the cores, such as WAFL parallelization, exempt processing, and CPU pinning. The CPU utilization reported by the sysstat command is an average across all cores and domains, and does not reflect the actual CPU activity or availability for each domain. Therefore, the CPU is not a first-order monitoring metric for ONTAP, and other metrics such as latency, throughput, and queue depth should be considered first. References = What is CPU utilization in Data ONTAP: Scheduling and Monitoring?, How to measure CPU utilization, What are CPU as a compute resource and the CPU domains in ONTAP 9?, Monitoring CPU utilization before ONTAP upgrade

• The AUSO feature is a MetroCluster functionality that enables an automatic switchover to the surviving site in the event of a disaster that affects one site1.
• The AUSO feature is only available in MetroCluster FC configurations, which use Fibre Channel (FC) switches and FC-to-SAS bridges to connect the nodes and disk shelves across sites1.
• MetroCluster IP configurations, which use Ethernet switches and network adapters to connect the nodes and disk shelves across sites, do not support the AUSO feature2.
• Instead, MetroCluster IP configurations use the ONTAP Mediator service, which is a software component that monitors the health and connectivity of the MetroCluster nodes and initiates a Mediator-assisted unplanned switchover when a disaster occurs3.
• The Mediator-assisted unplanned switchover is similar to the AUSO feature, but it requires the ONTAP Mediator service to be configured and running on a separate host3.
• Therefore, you would tell your customer that the AUSO feature is not available in MetroCluster IP installations by design, and that they need to use the ONTAP Mediator service instead for disaster recovery. References:
• 1: Understanding MetroCluster data protection and disaster recovery, ONTAP MetroCluster Documentation Center
• 2: Differences among the ONTAP MetroCluster configurations, ONTAP MetroCluster Documentation Center
• 3: Configure the ONTAP Mediator service from a MetroCluster IP configuration, ONTAP MetroCluster Documentation Center

• Having an Essentials package enables you to convert to another licensing option. This is true because the Essentials package is a capacity-based licensing option that allows you to pay for Cloud Volumes ONTAP per TiB of capacity. You can switch to another capacity-based package or to a Keystone Flex Subscription at any time1.
• BYOL licenses are purchased directly from NetApp. This is true because BYOL stands for Bring Your Own License, which means you need to obtain a license from NetApp before deploying Cloud Volumes ONTAP systems in any cloud provider2.
• Capacity-based license packages support only single-node configurations. This is false because capacity-based license packages support both single-node and HA configurations1.
• AWS Marketplace contracts cannot be mixed with BYOL. This is false because you can mix AWS Marketplace contracts with BYOL as long as the license type matches the instance type3. References: 1: Cloud Volumes ONTAP licensing | NetApp Documentation 2: Set up licensing for Cloud Volumes ONTAP in Google Cloud - NetApp 3: Set up licensing for Cloud Volumes ONTAP in AWS - NetApp

= The NetApp sanlun command is a tool that returns information about the LUNs mapped to your host, multipathing, and information necessary to create initiator groups. It is part of the Linux Unified Host Utilities package, which also includes other tools to manage NetApp storage, such as failover policies and physical paths. To run the sanlun command, you must install the Host Utilities package on your Linux host. The other options are not relevant for this scenario, as they are either not required or not compatible with the Linux host. References = Install Linux Unified Host Utilities 7.1, SAN Toolkit

Here is my reasoning:

• The system node hardware unified-connect show command displays the status and configuration of the Unified Connect ports on a node1. This command can help you identify if the ports are configured correctly and if they have any errors or faults.
• The ports 0e and 0f on the AFF A300 are 10GbE ports that support both Ethernet and Fibre Channel over Ethernet (FCoE) protocols2. These ports are part of the Unified Connect feature, which enables you to use the same physical port for different protocols without requiring additional hardware3.
• If the ports are offline, it could indicate a problem with the port configuration, the cable connection, the switch configuration, or the protocol settings. The system node hardware unified-connect show command can help you troubleshoot these issues by showing you the port mode, speed, duplex, state, and error count1.
• The other commands in the options are not as helpful for troubleshooting the port issue, because they show different information that is not related to the Unified Connect feature or the port status. For example:

Here are some references that might help you:

1: system node hardware unified-connect show - NetApp 2: AFF A300 system installation - NetApp 3: Unified Connect - NetApp 4: vserver fcp wwpn-alias show - NetApp 5: storage port show - NetApp 6: vserver fcp interface show - NetApp

• A LIF (Logical Interface) is a logical entity that represents a network connection point on a node1.
• A VIP LIF (Virtual IP LIF) is a LIF that can fail over across subnets within an IPspace2.
• BGP (Border Gateway Protocol) is a routing protocol that enables VIP LIFs to advertise their IP addresses to external routers and to update the routing tables when a failover occurs3.
• To connect a NetApp ONTAP cluster to a complex network that requires LIFs to fail over across subnets, you need to configure VIP LIFs using BGP on the cluster and on the external routers3.
• This way, you can ensure that the network traffic is routed to the optimal node and port for each VIP LIF, and that the network connectivity is maintained in the event of a node or port failure3. References:
• 1: Logical Interfaces, ONTAP 9 Documentation Center
• 2: VIP LIFs, ONTAP 9 Documentation Center
• 3: Configuring BGP on a cluster, ONTAP 9 Documentation Center