vSAN Health Test ‘Network latency check’ status changed from ‘yellow’ to ‘green’

vCenter alarm: vSAN Health Test ‘Network latency check’ status changed from ‘yellow’ to ‘green’

The change in status from “yellow” to “green” in the vSAN Health Test “Network Latency Check” likely indicates that the network latency has improved to a level that is within the acceptable range for vSAN.

In vSAN, network latency is one of the key factors that can impact the performance and overall health of the vSAN cluster. A yellow status in the network latency check typically means that the network latency is high, but still within an acceptable range. A green status, on the other hand, indicates that the network latency is within an acceptable range and is not causing any problems for the vSAN cluster.

It’s important to regularly monitor the health of your vSAN cluster, including the network latency, to ensure that the cluster is operating optimally and to quickly identify and resolve any potential issues.

Where I can check the vSAN ‘Network latency check’ status in the vCenter?

You can check the status of the “Network Latency Check” in the vSAN Health Check section of the vCenter Server. Here’s how:

1. Log in to vCenter Server using the vSphere Client.
2. Navigate to the “Hosts and Clusters” view.
3. Select the vSAN cluster in question.
4. Click on the “Monitor” tab.
5. Under the “vSAN” section, click on the “Health” option.
6. In the “Health” section, you will see the “vSAN Health Check” section.
7. In the “vSAN Health Check” section, look for the “Network Latency Check” item.
8. The status of the “Network Latency Check” will be displayed next to the item.

If the status of the “Network Latency Check” is yellow, it means that the network latency is high, but still within an acceptable range. If the status is green, it means that the network latency is within an acceptable range and is not causing any problems for the vSAN cluster. If the status is red, it means that the network latency is outside of the acceptable range and could be causing issues for the vSAN cluster. In that case, you should take action to resolve the issue and improve the network latency.

How to fix the vSAN Network latency issue?

Fixing vSAN network latency issues involves identifying the root cause of the problem and taking steps to resolve it. Here are some common steps to help resolve vSAN network latency issues:

1. Verify network configuration: Ensure that the network configuration is correct and meets the requirements for vSAN. This includes verifying network cabling, switches, and adapter settings.
2. Check network utilization: Monitor network utilization to ensure that there is enough bandwidth available for vSAN traffic. If the network is congested, consider upgrading to a higher-bandwidth network or adding additional network adapters to increase bandwidth.
3. Check for network errors: Monitor the network for errors, such as dropped packets or CRC errors, which can cause high latency and reduce network performance.
4. Check for network latency on physical switches: Check for network latency on the physical switches to ensure that they are not the source of the problem.
5. Enable Jumbo Frames: Enabling Jumbo Frames on the vSAN network can reduce the amount of overhead required for network communication, reducing latency.
6. Disable TCP Offloading: TCP Offloading can cause increased latency, so disabling it can help resolve vSAN network latency issues.
7. Check for physical network issues: Check for physical network issues, such as cabling problems or switch failure, that may be causing the network latency issues.
8. Check for virtual network issues: Check for virtual network issues, such as improper network adapter settings, that may be causing the network latency issues.
9. Load balance the vSAN traffic: Load balance the vSAN traffic across multiple network adapters to reduce the impact of network congestion on vSAN performance.

These are just some of the common steps to help resolve vSAN network latency issues. The specific steps that you need to take to resolve the issue will depend on the root cause of the problem. If you are unable to resolve the issue on your own, consider contacting VMware support or an experienced vSAN administrator for further assistance.

Is there any link between ESXi host high CPU utilization with vSAN Network latency?

High CPU utilization on an ESXi host can potentially impact vSAN network latency, but it is not a direct link.

In a vSAN environment, the vSAN network is used for communication between the ESXi hosts, which is critical for maintaining data availability and integrity. If one of the ESXi hosts in the vSAN cluster is experiencing high CPU utilization, it can potentially affect the vSAN network performance by consuming network bandwidth and causing network congestion.

Additionally, if the high CPU utilization is caused by a resource-intensive application or service running on the ESXi host, it can also impact the overall performance of the host and potentially affect the performance of other workloads and services running on the host. This can result in increased latency and potentially impact the vSAN network performance.

Therefore, it’s important to monitor the CPU utilization of your ESXi hosts and to address any issues that arise promptly to ensure that they are operating optimally.

Which are the misconfigurations that will impact vSAN health?

There are several misconfigurations that can impact the health of a vSAN environment. Some of the most common misconfigurations include:

1. Disk Group Configuration: Incorrect disk group configuration, such as placing hot data on a disk group with slow disks, can impact the performance and health of the vSAN environment.
2. Network Configuration: Improper network configuration, such as incorrect network adapter settings or incorrect switch configuration, can impact the performance and health of the vSAN environment.
3. Disk Settings: Improper disk settings, such as incorrect queue depth or I/O scheduler settings, can impact the performance and health of the vSAN environment.
4. Memory Configuration: Insufficient memory configuration can impact the performance and health of the vSAN environment, leading to increased latency and reduced I/O performance.
5. CPU Configuration: Insufficient CPU resources can impact the performance and health of the vSAN environment, leading to increased latency and reduced I/O performance.
6. Load Balancing: Improper load balancing of vSAN traffic can impact the performance and health of the vSAN environment, leading to increased latency and reduced I/O performance.
7. Overcommitment of Resources: Overcommitment of vSAN resources, such as CPU, memory, and storage, can impact the performance and health of the vSAN environment, leading to increased latency and reduced I/O performance.

These are some of the most common misconfigurations that can impact the health of a vSAN environment. To ensure the health and performance of your vSAN environment, it’s important to follow best practices for configuration and to regularly monitor the health and performance of your vSAN cluster.