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

= The NetApp Cloud Volumes ONTAP Release Notes provide the most up-to-date and accurate information about the storage limits for different cloud platforms, licenses, and configurations. The release notes also include details about supported features, known issues, and limitations for each version of Cloud Volumes ONTAP. References = Storage limits - NetApp, Storage limits | NetApp Documentation, Storage limits in AWS | NetApp Documentation, Storage limits in Azure | NetApp Documentation

• The error message indicates that the ONTAP Select Deploy VM cannot connect to the vCenter server due to a network issue1.
• One possible cause of this issue is that the IP address of the ONTAP Select Deploy VM is conflicting with another device on the same network2.
• To correct this problem, you need to change the IP address of the ONTAP Select Deploy VM to a unique and valid address that can reach the vCenter server2.
• You can change the IP address of the ONTAP Select Deploy VM by using the Deploy web interface or the Deploy CLI2.
• After changing the IP address, you need to restart the Deploy services and re-add the vCenter server to the inventory2. References:
• 1: Credential authentication failed with: HostConnectionFailed, NetApp Knowledge Base
• 2: Changing the IP address of the Deploy VM, ONTAP Select 9 Documentation Center

= The FIFO message before NMI is useful for investigating the issue because it shows the state of the system before the non-maskable interrupt (NMI) was triggered by the L2 watchdog timeout. The FIFO message contains information about the CPU registers, the stack pointer, the instruction pointer, and the last executed instructions. This can help identify the cause of the system hang or deadlock that led to the watchdog reset. The other FIFO messages are not useful because they show the state of the system after the reset or shutdown, which may not reflect the original problem. References = https://kb.netapp.com/onprem/ontap/hardware/Handling_L2_Watchdog_Resets_on_the_FAS8200_and_AFF_A300_platforms

https://docs.netapp.com/us-en/ontap-metrocluster/install-ip/task_sw_config_restore_defaults.html

The VMware feature that is supported by ONTAP software to identify and follow I/Os from each VM on the shared FC LUN-backed datastores is Virtual machine ID (VMID). VMID is a unique identifier assigned to each VM by the vCenter Server. ONTAP software can use VMID to map the VMs to the FC LUNs and provide visibility into the I/O performance and latency of each VM. This feature is also known as Virtual Storage Console (VSC) for VMware vSphere12. References: 1:Virtual Storage Console for VMware vSphere | NetApp Documentation 2: How to use Virtual Storage Console (VSC) to monitor the performance of virtual machines - NetApp Knowledge Base

 The mgwd user space process is responsible for managing the cluster configuration and providing the management interface for ONTAP. If this process crashes, it may generate a core dump file in the /mroot/etc/mgwd/core directory of the node. To access this directory, you need to log in to the systemshell, which is a Linux shell that runs on the node. The systemshell can be accessed by logging in to the nodeshell using the node console and then running the systemshell command. The nodeshell is a custom shell that provides access to ONTAP commands and utilities. The service processor and the clustershell are not relevant for collecting core dumps from the mgwd process. References = ONTAP 9 Cluster Administration, page 29-30; ONTAP 9 Troubleshooting Guide, page 23-24.

= When a SnapMirror resync operation is performed, the destination volume is reverted to the most recent common snapshot copy with the source volume. Any newer snapshot copies that exist on the destination volume are deleted automatically, unless they are marked as busy or locked. This is done to ensure that the destination volume is consistent with the source volume and to avoid data loss or corruption. Therefore, if the customer complains about missing snapshot copies on the destination volume after a SnapMirror resync, the most likely cause is that those snapshot copies were newer than the common snapshot that was chosen for resync and were removed automatically by the system. References = SnapMirror resync operation, SnapMirror resync or update failed No Snapshot copies found on volume, Even though there is common snapshot, SnapMirror resync fails with error: No common snapshot copy found between source and destination volume

 To assign storage access to an NVMe protocol host, you need to configure the following objects:

• The NVMe subsystem, which is a logical entity that represents a group of NVMe namespaces that can be accessed by one or more hosts1.
• An NVMe LIF, which is a logical interface that provides network connectivity for the NVMe subsystem2.
• The NVMe namespace, which is a logical volume that is exposed to the host as an NVMe device1.

You do not need to configure the NVMe broadcast domain or the NVMe LUN, as these are not relevant for NVMe protocol host access. References = 1: Configuring NVMe-oF - Hitachi Vantara Knowledge 2: Basic VMware NVMe Architecture and Components

 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

• 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

= 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

 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

• A Twinax cable is a type of copper cable that is used to connect cluster ports to cluster switches1.
• A cluster port is a network port that is configured for cluster communication and data access2.
• A cluster switch is a network switch that is used to interconnect the nodes in a cluster and provide redundancy and load balancing3.
• A cluster network is a network that enables cluster communication and data access between the nodes in a cluster and external clients4.
• A cluster network can be degraded due to various reasons, such as misconfiguration, malfunction, or excessive link errors on the cluster ports or the cluster switches.
• Link errors are errors that occur on the physical layer of the network, such as CRC errors, length errors, alignment errors, or dropped packets.
• Link errors can indicate a problem with the cable, the switch port, the network interface card (NIC), or the cable connector.
• In this scenario, the alert messages state that the cluster network has degraded and the errors are being generated from Node 2, interface e0b.
• The first step to solve this problem is to replace the Twinax cable between Node 2, interface e0b and the NetApp CN1610 switch, as this could be the source of the link errors.
• Replacing the cable could resolve the issue and restore the cluster network to a healthy state.
• If replacing the cable does not solve the problem, then other steps may be required, such as checking the switch port, the NIC, or the cable connector, or replacing the switch or the motherboard. References:
• 1: Cluster network cabling, ONTAP 9 Documentation Center
• 2: Cluster ports, ONTAP 9 Documentation Center
• 3: Cluster switches, ONTAP 9 Documentation Center
• 4: Cluster network, ONTAP 9 Documentation Center
• [5]: How to troubleshoot CLUSTER NETWORK DEGRADED error messages, NetApp Knowledge Base
• [6]: Cluster network degraded due to high CRC errors on cluster ports, NetApp Knowledge Base

To access a LUN on a FAS 8300 system from a VMware ESXi server through the FC protocol, the customer must configure the FC service on the SVM that owns the LUN. The FC service enables the SVM to act as an FC target and communicate with the FC initiators on the host. Without the FC service, the LUN will not be visible to the host, even if the LUN is mapped to an igroup and the FC LIFs are up. The exhibit shows that the FC service is not configured on the SVM, as theoutput of the command vserver fcp initiator show -vserver SVM1 is empty. Therefore, the reason for the problem is that the FC service has not been configured on the SVM. References = Configure an SVM for FC, Create an FC protocol service, Single IQN iSCSI session with ESXi on ONTAP when igroup has two IQNs

• The question describes a scenario where the controller and client have a significant difference in their reported latency for the same datastores.
• The controller’s latency is 1 ms, which is within the normal range for ONTAP-based datastores1.
• The client’s latency is 15 ms, which is much higher than the controller’s latency and could indicate a performance issue on the client side2.
• Therefore, the next step is to investigate the client that reports high latency and identify the possible causes, such as network congestion, misconfiguration, resource contention, or application issues23.
• The other options are not relevant or appropriate for this scenario, because:
• ONTAP 9 Performance - Resolution Guide - NetApp Knowledge Base
• Performance troubleshooting - NetApp
• How to troubleshoot performance issues in Data ONTAP 8 7-mode
• Cluster interconnect network - NetApp
• How to generate a sync core on a node - NetApp