The performance issue for the database VM is related to large block-size I/O operations over iSCSI, which connects to a Nutanix volume group. The VM has a dedicated NIC for iSCSI traffic, but a single NIC can become a bottleneck for large I/O operations, especially for a high-performance workload like a database. To improve performance, the administrator shouldadd an additional NIC for iSCSI connectivity and enable MPIO (Multipath I/O). This approach allows the VM to use multiple network paths for iSCSI traffic, increasing throughput and reducing latency for large block-size I/O operations.
TheNutanix Unified Storage Administration (NUSA)course states, “For high-performance workloads using Nutanix Volumes over iSCSI, enabling MPIO with multiple NICs on the VM can significantly improve I/O performance, especially for large block-size operations.” MPIO allows the VM to establish multiple iSCSI sessions to the Nutanix volume group, distributing I/O traffic across the available NICs and Controller Virtual Machines (CVMs) in the cluster. This is particularly effective for database workloads, which often involve large sequential I/O operations.
TheNutanix Certified Professional - Unified Storage (NCP-US)study guide further elaborates that “adding a second NIC for iSCSI traffic and configuring MPIO ensures load balancing and failover for iSCSI sessions, optimizing performance for VMs with high I/O demands, such as databases.” By adding another NIC, the VM can establish additional iSCSI paths to the volume group’s iSCSI Data Services IP (DSIP), leveraging the cluster’s distributed architecture to handle large block-size I/O more efficiently.
The other options are incorrect:
Add additional virtual disks to the volume group: Adding more virtual disks does not address the network bottleneck caused by a single iSCSI NIC and may not improve performance for large block-size I/O operations.
Increase the iSCSI adapter maximum transfer length: Adjusting the maximum transfer length (MTU) might help with network efficiency, but it does not address the fundamental issue of a single NIC being a bottleneck for large I/O operations. MPIO with multiple NICs is a more effective solution.
Locate the iSCSI NIC on the same VLAN as the cluster DSIP: While placing the iSCSI NIC on the same VLAN as the DSIP can reduce latency by avoiding inter-VLAN routing, the primary issue here is the single NIC bottleneck, not VLAN configuration. MPIO with multiple NICs provides a better performance improvement.
The NUSA course documentation emphasizes that “for VMs with large block-size I/O requirements, such as databases, using MPIO with multiple iSCSI NICs ensures optimal performance by distributing traffic across multiple paths to the Nutanix volume group.”
[References:, Nutanix Unified Storage Administration (NUSA) Course, Section on Nutanix Volumes: “Optimizing iSCSI performance with MPIO for high-performance workloads.”, Nutanix Certified Professional - Unified Storage (NCP-US) Study Guide, Topic 4: Troubleshoot Nutanix Unified Storage, Subtopic: “Performance troubleshooting for iSCSI-based VMs.”, Nutanix Documentation (https://www.nutanix.com), Nutanix Volumes Administration Guide: “Configuring MPIO for iSCSI performance optimization.”, ]
