NS0-593 Exam Dumps : NetApp Certified Support Engineer ONTAP Specialist

 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

• 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

• 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]