Netapp NS0-593 - NetApp Certified Support Engineer ONTAP Specialist

= According to the NetApp Knowledge Base1, while Cloud Volumes ONTAP supports FlexGroup volumes, Cloud Manager does not. If you create a FlexGroup volume from System Manager or from the CLI, then you should set Cloud Manager’s Capacity Management mode to Manual. Automatic mode might not work properly with FlexGroup volumes. The other options are incorrect because Cloud Volumes ONTAP does support FlexGroup volumes2, the CapacityManagement Mode should not be set to Automatic, and Cloud Manager is not required to provision the FlexGroup volume3. References = 1, 2, 3

The error message indicates that the specified path “/vol1” does not exist in the namespace belonging to Vserver “svm1”. This means that the volume “vol1” has not been mounted to the Vserver’s namespace, which is required for creating a share. The volume type, the CIFS service status, and the CIFS service mode are not relevant to the error. References = https://www.netapp.com/support-and-training/netapp-learning-services/certifications/support-engineer/

https://mysupport.netapp.com/site/docs-and-kb

= 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

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

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

 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

= To prevent file ID conflicts in a FlexGroup volume, you need to enable 64-bit NFSv3 and NFSv4 identifiers on the SVM that hosts the FlexGroup volume. This allows the SVM to use 64-bit file system IDs (FSIDs) and file IDs, which are unique across the cluster and can accommodate a large number of files. The -v3-64bit-identifiers and -v4-64bit-identifiers parameters enable this feature for NFSv3 and NFSv4 protocols respectively. References = Editing FlexGroup volumes, Enabling 64-bit NFSv3 identifiers on an SVM, 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

SnapMirror is a data replication technology that allows efficient and flexible data protection and disaster recovery for NetApp ONTAP storage systems1

SnapMirror transfers data between source and destination volumes using a network connection. SnapMirror can use storage efficiency features such as compression and deduplication to reduce the amount of data transferred and stored1

SnapMirror transfers are scheduled and controlled by policies that define the frequency, retention, and priority of the transfers. SnapMirror policies can also specify the network bandwidth limit for the transfers2

SnapMirror transfers are considered background tasks that run in the absence of user workload. SnapMirror transfers can consume CPU and disk resources on both source and destination systems, depending on the amount and type of data being replicated3

SnapMirror transfers can throttle up or down depending on the availability of system resources and network bandwidth. SnapMirror transfers will throttle up when there is nouser workload, and throttle down when there is user workload. This is to ensure that SnapMirror transfers do not impact the performance of user operations3

Therefore, if a customer is concerned with high CPU and disk utilization on their SnapMirror destination system, the best answer is to explain that background tasks such as SnapMirror throttle up in the absence of user workload. This is normal and expected behavior, and it does not indicate a problem with the system3

References:

1: ONTAP 9 Data Protection - SnapMirror - The Open Group 2: ONTAP 9 Data Protection - SnapMirror Policies - The Open Group 3: SnapMirror storage efficiency configurations and behavior - Resolution Guide - NetApp Knowledge Base