Netapp NS0-593 NetApp Certified Support Engineer ONTAP Specialist Exam Practice Test

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

• The mailbox disks are the first two disks of the root aggregate on each node of an HA pair. They store the HA state information and the panic dump files. The mailbox disks are used for communication between the HA partners and for takeover and giveback operations1
• The mailbox destroy local command is used to destroy the mailbox disks on the local node. This command is only available in maintenance mode and should be used with extreme caution. The command is intended for situations where the mailbox disks are corrupted or inaccessible and need to be recreated2
• If the mailbox destroy local command is executed on a node that is in takeover mode, the node will panic with the message “Permanent errors on all HA mailbox disks”. This is because the node will lose the HA state information and the panic dump files of the partner node, and will not be able to communicate with the partner node or perform a giveback operation3
• Therefore, if the motherboard of Node-01 is being replaced, and a takeover was initiated from Node-02, and Node-02 panics showing the string “Permanent errors on all HA mailbox disks”, the most likely cause is that the mailbox destroy local command was executed on Node-02 while in maintenance mode. This is a serious error that can result in data loss and system downtime4

References:

1: ONTAP 9 - High-Availability Configuration Guide - The Open Group 2: ONTAP 9 - Commands: Manual Page Reference - The Open Group 3: How to troubleshoot a “Permanent errors on all HA mailbox disks” panic - NetApp Knowledge Base 4: One node PANIC : Permanent errors on all HA mailbox disks - NetApp Knowledge Base

• 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

 To create a packet trace for all clients on the 192.168.9.0/24 subnet, you have to run the packet trace on the interface that has an IP address in the same subnet. According to the exhibit, the only interface that matches this criterion is e2a-100, which has an IP address of 192.168.3.1/24. The other interfaces have IP addresses in different subnets, such as 10.92.4.202/16, 10.91.3.132/24, 10.95.7.114/24, and 10.92.6.200/16. Therefore, the correct answer is B. e2a-100. References = How to capture packet traces on ONTAP 9.10+ systems, How to capture packet traces (tcpdump) on ONTAP 9.2 to 9.9 systems, How to download captured packet traces from ONTAP

 According to the NetApp Knowledge Base, adding a second NS224 shelf to an existing stack can cause the first shelf ID to change to the serial number if the cables are not connected properly1. This can also result in a Medium Impact error message: Shelves with both connections via the same SAS path detected2. This situation is not normal for a NetApp AFF A800 system andcan affect performance and availability. The cables should be reconnected according to the SAS cabling rules and concepts for shelves with IOM12/IOM12B modules3 and the controller-to-stack cabling worksheet template for quad-pathed connectivity4. References = Shelves with both connections via the same SAS path detected, Adding a second NS224 shelf, changes first shelf ID to the serial number, SAS cabling rules and concepts - shelves with IOM12/IOM12B modules, Controller-to-stack cabling worksheet template for quad-pathed connectivity.

• IQN stands for iSCSI Qualified Name, which is a unique identifier for an iSCSI initiator or target1.
• ONTAP uses IQN to authenticate and authorize iSCSI sessions2.
• If two hosts have the same IQN, they will cause a conflict and ONTAP will reject the new session request from the second host3.
• This will result in the host losing the connection to the iSCSI target and then reporting that the session was reestablished, as shown in the exhibit.
• To avoid this problem, each host should have a unique IQN. References:
• iSCSI Qualified Name (IQN) - NetApp
• iSCSI authentication and authorization - NetApp
• Troubleshooting iSCSI issues - NetApp
• [Configuring iSCSI initiators - NetApp]

= 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

= The cause of the customer’s problem is that the port has an incorrect SFP inserted. According to the AutoSupport data, the node 1 has a device type of XL710 BQ, which is a 40GbE adapter that requires a QSFP+ transceiver1. However, the part number of the adapter is 111-02590, which is a 10GbE adapter that requires a SFP+ transceiver2. This mismatch prevents the link from coming up on node 1. The customer should replace the adapter with the correct one or use a compatible transceiver for the existing adapter. References = 1: NetApp Hardware Universe - X1144A 2: NetApp Hardware Universe - X1147A

= 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 ONTAP command that will help isolate a possible MTU mismatch is network ping -lif jumbo_01 -vserver svm1_cluster1 -destination 192.168.0.210 -disallow-fragmentation true -packet-size 5000. This command will send a ping packet of 5000 bytes from the logical interface (LIF) jumbo_01 to the destination IP address 192.168.0.210, without allowing fragmentation. If the ping fails, it means that there is an MTU mismatch somewhere along the path. If the ping succeeds, it means that the MTU is consistent and the problem is elsewhere12. References: 1: Check the MTU network setting on the storage system |NetApp Documentation 2: How to adjust the MTU for an ONTAP interface - NetApp Knowledge Base

• 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

 = The multiprotocol volume allows clients to access files using both NFS and SMB protocols. The NFS protocol is case-sensitive, meaning that Test.txt and TEST~1.TXT are two different files. The SMB protocol is case-insensitive, meaning that it treats uppercase and lowercase letters as the same when searching for a file. Therefore, when the user opened the file from a Windows system using SMB, the system could not distinguish between Test.txt and TEST~1.TXT and displayed one of them arbitrarily. This could lead to confusion and data loss if the user modified or deleted the wrong file. References = Client protocols; Multiprotocol NAS in NetApp ONTAP Overview and Best Practices, page 30-31.

• 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 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

• 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

 According to the NetApp Knowledge Base, packet traces are stored in the /etc/log/packet_traces directory of the node hosting the LIF. This applies to ONTAP 9.10 and above systems. For ONTAP 9.2 to 9.9 systems, the procedure to capture packet traces is similar, but the command syntax is slightly different. For ONTAP pre-9.2 systems, the procedure is different and requires the use of the tcpdump command. References = How to capture packet traces on ONTAP 9.10+ systems, How to capture packet traces (tcpdump) on ONTAP 9.2 to 9.9 systems, How to capture packet traces in ONTAP pre-9.2

= 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

 FlexGroup requires CIFS shares to use the Continuously Available Feature, which enables transparent failover and recovery of SMB sessions in the event of a node failure or takeover. This feature is only supported by Windows 8 and later clients, and some printers and scanners may not support it either. Therefore, these older Windows XP clients and some printers and scanners are unable to access a FlexGroup over CIFS. References = Supported and unsupported configurations for FlexGroup volumes, NetApp ONTAP FlexGroup volumes — Best practices and implementation guide (page 24)