PowerShell script to identify virtual machines (VMs) that have been cloned from a snapshot

The script below demonstrates how you can list VMs cloned from snapshots. It checks each VM to see if it has a parent snapshot by examining its disk’s parent disk. If the parent disk is a snapshot, it implies the VM was cloned from that snapshot.

# Connect to vCenter Server
$vcServer = 'your-vcenter-server'
Connect-VIServer -Server $vcServer -Credential (Get-Credential)

# Function to check if a VM is cloned from a snapshot
function Check-VMClonedFromSnapshot {
param (
[VMware.VimAutomation.ViCore.Impl.V1.Inventory.VirtualMachineImpl]$VM
)

$isClonedFromSnapshot = $false
$vmDisks = Get-HardDisk -VM $VM

foreach ($disk in $vmDisks) {
$diskInfo = $disk.ExtensionData.Backing
if ($diskInfo.Parent -ne $null) {
$parentDisk = Get-View -Id $diskInfo.Parent.VmSnapshot
if ($parentDisk -ne $null) {
$isClonedFromSnapshot = $true
break
}
}
}

return $isClonedFromSnapshot
}

# Get all VMs
$vms = Get-VM

# Check each VM and report if it is cloned from a snapshot
foreach ($vm in $vms) {
if (Check-VMClonedFromSnapshot -VM $vm) {
Write-Host "$($vm.Name) is cloned from a snapshot."
}
}

# Disconnect from vCenter Server
Disconnect-VIServer -Server $vcServer -Confirm:$false

Multiple VMs with multiple ISOs in VMware:

# Define variables
$vcenterServer = "your_vcenter_server"
$username = "your_username"
$password = "your_password"
$clusterName = "your_cluster_name"
$datastoreName = "your_datastore_name"
$vmFolder = "your_vm_folder"
$vmNames = @("VM1", "VM2", "VM3") # Array of VM names
$isoPaths = @("path/to/iso1.iso", "path/to/iso2.iso", "path/to/iso3.iso") # Array of ISO file paths
$guestOS = "Windows Server 2022" # Guest OS for all VMs
$memoryMB = 2048 # Memory assigned to all VMs
$cpuCount = 1 # Number of CPUs assigned to all VMs
$diskSizeGB = 40 # Size of the hard disk for all VMs

# Connect to vCenter Server
Connect-VIServer -Server $vcenterServer -User $username -Password $password

# Get the cluster object
$cluster = Get-Cluster -Name $clusterName

# Get the datastore object
$datastore = Get-Datastore -Name $datastoreName

# Get the VM folder object
$vmFolder = Get-Folder -Path $vmFolder

# Loop through each VM name and ISO
foreach ($vmName, $isoPath in @($vmNames, $isoPaths)) {
# Create a new VM
$vm = New-VM -Name $vmName -Cluster $cluster -Datastore $datastore -Path $vmFolder -GuestOS $guestOS

# Set VM memory and CPU
$vm.ResourceAllocation.Memory = $memoryMB * 1024 * 1024
$vm.ResourceAllocation.CpuAllocation.Reservation = $cpuCount
$vm.ResourceAllocation.CpuAllocation.Limit = $cpuCount

# Add a hard disk
$disk = New-HardDisk -VM $vm -CapacityGB $diskSizeGB

# Add CD/DVD drive and connect ISO
$cdrom = New-CDDrive -VM $vm -IsoPath $isoPath -StartConnected

# Power on the VM
Start-VM -VM $vm
}

# Disconnect from vCenter Server
Disconnect-VIServer


# Note:
* This script is a basic example and may need modifications depending on your specific environment.
* Make sure you have the necessary permissions to perform these actions in vCenter Server.
* You can customize the script by adding additional parameters for VM configuration, such as network settings, NICs, etc.

I hope this helps! Let me know if you have any other questions.

VSS and SQL VMs in VMware Environment

For the modern DBA, ensuring consistent and reliable backups is a constant quest. While various backup methods exist, none achieve true data integrity without the unsung heroes – VSS writers and providers. These components work silently behind the scenes, guaranteeing accurate snapshots of your SQL Server instances during backup operations. In this blog, we’ll delve into the world of VSS, exploring its significance, functionality, and recovery techniques, equipped with powerful PowerShell commands.

Why VSS Matters in the SQL Realm:

Imagine backing up a running SQL Server without VSS. Active transactions, open files, and ongoing operations could lead to inconsistent and unusable backups. This nightmare scenario highlights the critical role of VSS:

  • Application-Aware Backups: VSS writers, specifically the dedicated SQL Writer, interact with SQL Server, ensuring it quiesces itself before the snapshot. This guarantees a consistent state of databases, even during peak activity.
  • Minimized Downtime: By coordinating with writers, VSS freezes SQL Server for brief periods, minimizing backup impact on server performance. This translates to minimal disruption for users and applications.
  • Reliable Disaster Recovery: Consistent backups form the bedrock of successful disaster recovery. By ensuring data integrity, VSS paves the way for seamless database restoration in case of outages.

The VSS Workflow: A Peek into the Backup Symphony:

  1. Backup Application Initiates the Show: Your chosen backup application sends a backup request to the VSS provider.
  2. VSS Provider Takes the Stage: The provider, acting as the conductor, informs registered writers (including the SQL Writer) about the upcoming backup performance.
  3. SQL Writer Prepares for its Cue: Upon receiving the notification, the SQL Writer springs into action. It flushes caches, commits transactions, and ensures databases are in a stable state for backup.
  4. Snapshot Time!: The provider creates a volume shadow copy, essentially capturing a frozen image of the system state, including SQL Server databases.
  5. Backup Application Reads the Script: The application reads data from the consistent snapshot, guaranteeing application consistency within the backup.
  6. Curtain Call: The provider releases the SQL Writer from its frozen state, and the backup process concludes.

When the Show Doesn’t Go On: Troubleshooting Failed VSS Writers and Providers:

Even the best actors can face hiccups. When VSS writers or providers fail, backups can crash and burn. Let’s equip ourselves with PowerShell commands to troubleshoot and recover:

1. Identify the Culprit:

Get-VSSWriter -ErrorAction SilentlyContinue | Where-Object {$_.LastExitCode -ne 0}

This command lists writers with errors. Look for the writer causing consistent issues, likely the “SQL Writer”.

2. Check the SQL Writer’s Status:

Get-VSSWriter -Name "SQL Writer" | Get-VSSWriterState

This command displays the writer’s state and any error messages, providing valuable clues to the problem.

3. Reset the SQL Writer: –> If needed

Reset-VSSWriter -Name "SQL Writer"

This attempt resets the writer’s state, potentially resolving temporary glitches.

4. Restart the SQL Writer Service:

Restart-Service MSSQL$SQLWriter

This restarts the associated service, which might be malfunctioning.

5. Re-register the SQL Writer:

Register-VSSWriter -Name "SQL Writer"

Re-registration can fix corrupt writer configurations.

6. Update SQL Server or VSS Writer:

Outdated software can harbor bugs. Check for updates from Microsoft and relevant vendors.

7. Exclude (as a Last Resort):

As a final option, consider excluding the problematic writer from backups. However, be aware of potential data inconsistencies.

Remember: These are general guidelines. Always consult your SQL Server and VSS writer documentation for specific troubleshooting steps.

Beyond Troubleshooting: Proactive Measures for a Seamless Backup Symphony:

  • Regularly monitor VSS writer status: Schedule checks to identify potential issues early on.
  • Test backups frequently: Perform periodic restores to confirm backup integrity and data consistency.
  • Stay updated: Apply recommended updates for SQL Server, VSS writer, and backup software.
  • Consider alternative backup methods: Explore options like native SQL Server backup tools or managed backup services for additional protection.

“esxtop” not displaying the output correctly

The TERM=xterm environment variable is not particularly crucial for the display of esxtop itself. However, setting the correct value for the TERM variable is important for ensuring that terminal applications, including esxtop, are displayed properly.

The TERM variable specifies the type of terminal that a user is employing. Different terminal types may have different capabilities and features. When you set TERM=xterm, you are essentially telling the system that your terminal emulator supports the xterm terminal type.

For esxtop, like many other terminal-based applications, setting the correct TERM variable helps in determining how the application interacts with the terminal emulator. It ensures that the application’s output is formatted and displayed appropriately, taking into account the capabilities of the terminal being used.

In the case of esxtop on VMware ESXi hosts, it’s generally run in a console environment or through an SSH session. If your terminal emulator is indeed xterm-compatible, the TERM=xterm setting is likely unnecessary, as modern terminal emulators often handle this automatically.

While running esxtop you might see below value which is not formatted :

Validate the current terminal declaration type::

[root@cshq-esx01:~] echo $TERM

xterm-256color

Change the type to :::TERM=xterm

[root@cshq-esx01:~] TERM=xterm

[root@cshq-esx01:~] echo $TERM

xterm

If you want a permanent solution and using Remote Desktop Manager ::

Terminal–> Types –> Environment Variables to “xterm” from “xterm-256color”

Clone operations and Snapshot operations

Clone operations and snapshot operations are distinct, each with its own purpose and function calls when using automation tools like PowerCLI or vSphere API.

Clone Operations

Function Call in PowerCLI: To clone a VM in PowerCLI, you would use the New-VM cmdlet with the -Template parameter, specifying the source VM to clone from.

New-VM -Name 'ClonedVM' -VM 'SourceVM' -Datastore 'TargetDatastore' -Location 'TargetResourcePool'

Function Call in vSphere API: In the vSphere API, you would call the CloneVM_Task method on the source VM managed object.

task = source_vm.CloneVM_Task(folder=dest_folder, name='ClonedVM', spec=clone_spec)

Difference Between Cloning and Snapshotting:

  • Cloning creates a separate, independent copy of a virtual machine. The new VM has its own set of files on the datastore and a unique identity within the vCenter environment.
  • Cloning is often used for deploying new VMs from a template or existing VM without affecting the original.

Snapshot Operations

Function Call in PowerCLI: To create a snapshot of a VM in PowerCLI, you would use the New-Snapshot cmdlet.

New-Snapshot -VM 'SourceVM' -Name 'SnapshotName' -Description 'SnapshotDescription'

Function Call in vSphere API: In the vSphere API, you would call the CreateSnapshot_Task method on the VM managed object.

task = vm.CreateSnapshot_Task(name='SnapshotName', description='SnapshotDescription', memory=False, quiesce=False)

Difference Between Cloning and Snapshotting:

  • A snapshot captures the state and data of a VM at a specific point in time. This includes the VM’s power state (on or off), the contents of the VM’s memory (if the snapshot includes the VM’s memory), and the current state of all the VM’s virtual disks.
  • Snapshots are used for point-in-time recovery, allowing you to revert to the exact state captured by the snapshot. They are not full copies and rely on the original disk files.

Examples

Cloning a VM:

  1. You have a VM called “WebServerTemplate” configured with your standard web server settings.
  2. You clone “WebServerTemplate” to create a new VM called “WebServer01”.
  3. “WebServer01” is now a separate VM with its settings identical to “WebServerTemplate” at the clone time but operates independently going forward.

Creating a Snapshot of a VM:

  1. You have a VM called “DatabaseServer” that is running a critical database.
  2. Before applying updates to the database software, you take a snapshot called “PreUpdateSnapshot”.
  3. After the snapshot, you proceed with the updates.
  4. If the updates cause issues, you can revert to the “PreUpdateSnapshot” to return the VM to the exact state it was in before the updates.

When performing snapshot and clone operations in a VMware environment, different files are created and used for each process. Here’s a breakdown of the file types associated with each operation:

Snapshot Operation Files:

When you take a snapshot of a VMware virtual machine, the following files are associated with the snapshot operation:

  1. Snapshot Descriptor Files (.vmsd and .vmsn):
    • .vmsd – This file contains the metadata about the snapshot and child snapshot information.
    • .vmsn – This file stores the state of the VM at the time the snapshot was taken. If the snapshot includes the memory, this file will also contain the VM’s memory contents.
  2. Snapshot Data Files (Delta disks, .vmdk):
    • Delta .vmdk – These are the differential files that store changes made to the VM disk after the snapshot was taken. They are often referred to as “delta disks” or “child disks.”

Example:

  • VM_Name-000001.vmdk – A delta disk created after the first snapshot.
  • VM_Name-000001-delta.vmdk – The differential file that stores the disk changes since the snapshot.
  1. Snapshot Configuration Files (.vmx and .vmxf):
    • These files are not created new for the snapshot; instead, they are updated to reference the current snapshot.

Clone Operation Files:

When you clone a VMware virtual machine, a new set of files is created for the clone, similar to the original VM’s files:

  1. Virtual Disk Files (.vmdk and -flat.vmdk):
    • .vmdk – The descriptor file for the virtual disk, which points to the actual data file.
    • -flat.vmdk – The data file that contains the cloned VM’s virtual disk data.
  2. VM Configuration File (.vmx):
    • .vmx – This is the primary configuration file that stores settings for the cloned VM.
  3. VM Team File (.vmxf):
    • .vmxf – An additional configuration file used if the VM is part of a team in VMware Workstation.
  4. BIOS Boot File (.nvram):
    • .nvram or .nvram– This file contains the BIOS state of the VM.
  5. Log Files (.log):
    • .log – These files contain log information about the VM’s operation and are created for the clone.

Example:

  • If you clone a VM named “ProdServer” to a VM named “TestServer”, you will get a new set of files like TestServer.vmdk, TestServer.vmx, TestServer.vmxf, and TestServer.nvram, among others.

In both operations, the directory structure on the datastore would also include a VM folder named after the VM (for clones) or the snapshot (as a subfolder for snapshots). The exact naming conventions for the files may vary depending on the version of the VMware product and the specific operations performed.

Keep in mind that during a cloning operation, if you opt to customize the clone (e.g., changing the network settings, hostname, etc.), you may also have a customization specification file (.vmtx) associated with the clone. This file stores the customization settings applied during the cloning process.

Moreover, during a clone operation, if you choose to clone from a snapshot point rather than the current state, the clone will be an exact copy of the VM at the point when the snapshot was taken, including the VM’s disk state as captured in the snapshot’s delta disk files.

Below you will find PowerShell examples using VMware PowerCLI to clone a virtual machine and to create a snapshot of a virtual machine. Before you can use these cmdlets, you need to install VMware PowerCLI and connect to your vCenter Server or ESXi host.

Cloning a Virtual Machine

To clone an existing VM to a new VM, you would use the New-VM cmdlet in PowerCLI. Here’s an example:

# Connect to vCenter
Connect-VIServer -Server 'vcenter_server_name' -User 'username' -Password 'password'

# Clone VM
$sourceVM = Get-VM -Name 'SourceVMName'
$targetDatastore = Get-Datastore -Name 'TargetDatastoreName'
$targetVMHost = Get-VMHost -Name 'ESXiHostName'
$location = Get-Folder -Name 'TargetLocationFolder' # The folder where the new VM will be located

New-VM -Name 'NewClonedVMName' -VM $sourceVM -Datastore $targetDatastore -VMHost $targetVMHost -Location $location

# Disconnect from vCenter
Disconnect-VIServer -Server 'vcenter_server_name' -Confirm:$false

Make sure to replace 'vcenter_server_name', 'username', 'password', 'SourceVMName', 'TargetDatastoreName', 'ESXiHostName', 'TargetLocationFolder', and 'NewClonedVMName' with your actual environment details.

Creating a Snapshot of a Virtual Machine

To create a snapshot of a VM, you would use the New-Snapshot cmdlet. Here’s an example:

# Connect to vCenter
Connect-VIServer -Server 'vcenter_server_name' -User 'username' -Password 'password'

# Create a snapshot
$vm = Get-VM -Name 'VMName'
$snapshotName = 'MySnapshotName'
$snapshotDescription = 'Snapshot before update'

New-Snapshot -VM $vm -Name $snapshotName -Description $snapshotDescription

# Disconnect from vCenter
Disconnect-VIServer -Server 'vcenter_server_name' -Confirm:$false

Replace 'vcenter_server_name', 'username', 'password', 'VMName', 'MySnapshotName', and 'Snapshot before update' with your details.

These examples assume you have the necessary permissions to perform these operations. Always test scripts in a non-production environment before running them in production.

Will CTK file cause performance issue in NFS

CTK file, or Change Tracking File, is used primarily for Change Block Tracking (CBT). CBT is a feature that helps in efficiently backing up virtual machines by tracking disk sectors that have changed. This information is crucial for incremental and differential backups, making the backup process faster and more efficient as only the changed blocks of data are backed up after the initial full backup.

Purpose of CTK Files in VMware

  1. Efficient Backup Operations: CTK files enable backup software to quickly identify which blocks of data have changed since the last backup. This reduces the amount of data that needs to be transferred and processed during each backup operation.
  2. Improved Backup Speed: By transferring only changed blocks, CBT minimizes the time and network bandwidth required for backups.
  3. Consistency and Reliability: CTK files help ensure that backups are consistent and reliable, as they track changes at the disk block level.

Impact of CTK Files on NFS Performance

Regarding latency in NFS (Network File System) environments, the use of CTK files and CBT can have some impact, but it’s generally minimal:

  1. Minimal Overhead: CBT typically introduces minimal overhead to the overall performance of the VM. The process of tracking changes is lightweight and should not significantly impact VM performance, even when VMs are stored on NFS datastores.
  2. Potential for Slight Increase in I/O: While CTK files themselves are small, they can lead to a slight increase in I/O operations as they track disk changes. However, this is usually negligible compared to the overall I/O operations of the VM.
  3. NFS Protocol Considerations: NFS performance depends on various factors, including network speed, NFS server performance, and the NFS version used. The impact of CTK files on NFS should be considered in the context of these broader performance factors.
  4. Backup Processes: The most noticeable impact might be during backup operations, as reading the changed blocks could increase I/O operations. However, this is offset by the reduced amount of data that needs to be backed up.

In summary, while CTK files are essential for efficient backup operations in VMware environments, their impact on NFS performance is typically minimal. It’s important to consider the overall storage and network configuration to ensure optimal performance.

Script to help you find all CTK files in a vCenter:

# Connect to the vCenter Server
Connect-VIServer -Server your_vcenter_server -User your_username -Password your_password

# Retrieve all VMs
$vms = Get-VM

# Find all CTK files
$ctkFiles = foreach ($vm in $vms) {
$vm.ExtensionData.LayoutEx.File | Where-Object { $_.Name -like "*.ctk" } | Select-Object @{N="VM";E={$vm.Name}}, Name
}

# Display the CTK files
$ctkFiles

# Disconnect from the vCenter Server
Disconnect-VIServer -Server your_vcenter_server -Confirm:$false

Use Get-LCMImage to store a particular version of VMware Tools to a variable

The Get-LCMImage cmdlet in VMware PowerCLI is designed for use with the Lifecycle Manager to manage software images, including VMware Tools. To store a particular version of VMware Tools to a variable using PowerCLI, you can follow these steps:

Open PowerCLI: First, make sure you have VMware PowerCLI installed on your system. Open the PowerCLI console.

Connect to vCenter Server: Use the Connect-VIServer cmdlet to connect to your vCenter server. Replace your_vcenter_server with the hostname or IP address of your vCenter server, and provide the appropriate username and password.

Connect-VIServer -Server your_vcenter_server -User your_username -Password your_password

Retrieve VMware Tools Images: Use the Get-LCMImage cmdlet to retrieve the list of available VMware Tools images. This cmdlet retrieves information about the software images managed by vSphere Lifecycle Manager.

$vmwareToolsImages = Get-LCMImage

Filter for Specific VMware Tools Version: You can filter the retrieved images for a specific version of VMware Tools. Replace specific_version with the desired version number.

$specificVmwareTools = $vmwareToolsImages | Where-Object { $_.Name -like "*VMware Tools*" -and $_.Version -eq "specific_version" }
  1. This command filters the images to find one that matches the name pattern of VMware Tools and has the specified version.
  2. Store to Variable: The filtered result is now stored in the $specificVmwareTools variable.
  3. Inspect the Variable: You can inspect the variable to confirm it contains the expected information.
$specificVmwareTools

If you encounter any issues or if the Get-LCMImage cmdlet does not provide the expected results, you may need to refer to the latest VMware PowerCLI documentation for updates or alternative cmdlets. The PowerCLI community forums can also be a helpful resource for troubleshooting and advice.

Automating the shutdown of an entire vSAN cluster

In VMware vCenter 7.0, automating the shutdown of an entire vSAN cluster is a critical operation, especially in environments requiring graceful shutdowns during power outages or other maintenance activities. While the vSphere Client provides an option to shut down the entire vSAN cluster manually, automating this task can be achieved using VMware PowerCLI or vSphere APIs. As of my last update in April 2023, here’s how you can approach it:

Using PowerCLI

VMware PowerCLI is a powerful command-line tool used for automating vSphere and vSAN tasks. You can use PowerCLI scripts to shut down VMs and hosts in a controlled manner. However, there might not be a direct PowerCLI cmdlet that corresponds to the “Shutdown Cluster” option in the vSphere Client. Instead, you can create a script that sequentially shuts down the VMs and then the hosts in the vSAN cluster. Here’s a basic outline of what such a script might look like:

Connect to vCenter Server:

Connect-VIServer -Server your_vcenter_server -User your_username -Password your_password

Get vSAN Cluster Reference:

$cluster = Get-Cluster "Your_vSAN_Cluster_Name"

Gracefully Shutdown VMs:

Get-VM -Location $cluster | Shutdown-VMGuest -Confirm:$false

Wait for VMs to Shutdown:

# You might want to add logic to wait for all VMs to be powered off

Shutdown ESXi Hosts:

Get-VMHost -Location $cluster | Stop-VMHost -Confirm:$false -Force

Disconnect from vCenter:

Disconnect-VIServer -Server your_vcenter_server -Confirm:$false

Using vSphere API

The vSphere API provides extensive capabilities and can be used for tasks such as shutting down clusters. You can make API calls to perform the shutdown tasks in a sequence similar to the PowerCLI script. The process involves making RESTful API calls or using the SOAP-based vSphere Web Services API to:

  1. List all VMs in the cluster.
  2. Power off these VMs.
  3. Then sequentially shut down the ESXi hosts.

Important Considerations

  • Testing: Thoroughly test your script in a non-production environment before implementing it in a production setting.
  • Error Handling: Implement robust error handling to deal with any issues during the shutdown process.
  • vSAN Stretched Cluster: If you are working with a vSAN stretched cluster, consider the implications of shutting down sites.
  • Automation Integration: For integration with external automation platforms (like vRealize Automation), use the respective APIs or orchestration tools.

Since automating a full cluster shutdown involves multiple critical operations, it’s important to ensure that the script or API calls are well-tested and handle all potential edge cases. For the most current information and advanced scripting, consulting VMware’s latest PowerCLI documentation and vSphere API Reference is recommended. Additionally, if you have specific requirements or need to handle complex scenarios, consider reaching out to VMware support or a VMware-certified professional.

vSAN Network Design Best Practices

VMware vSAN, a hyper-converged, software-defined storage product, utilizes internal hard disk drives and flash storage of ESXi hosts to create a pooled, shared storage resource. Proper network design is critical for vSAN performance and reliability. Here are some best practices for vSAN network design:

1. Network Speed and Consistency

  • Utilize a minimum of 10 GbE network speed for all-flash configurations. For hybrid configurations (flash and spinning disks), 1 GbE may be sufficient but 10 GbE is recommended for better performance.
  • Ensure consistent network performance across all ESXi hosts participating in the vSAN cluster.

2. Dedicated Physical Network Adapters

  • Dedicate physical network adapters exclusively for vSAN traffic. This isolation helps in managing and troubleshooting network traffic more effectively.

3. Redundancy and Failover

  • Implement redundant networking to avoid a single point of failure. This typically means having at least two network adapters per host dedicated to vSAN.
  • Configure network redundancy using either Link Aggregation Control Protocol (LACP) or simple active-standby uplink configuration.

4. Network Configuration

  • Use either Layer 2 or Layer 3 networking. Layer 2 is more common in vSAN deployments.
  • If using Layer 3, ensure that proper routing is configured and there is minimal latency between hosts.

5. Jumbo Frames

  • Consider enabling Jumbo Frames (MTU size of 9000 bytes) to improve network efficiency for large data block transfers. Ensure that all network devices and ESXi hosts in the vSAN cluster are configured to support Jumbo Frames.

6. Traffic Segmentation and Quality of Service (QoS)

  • Segregate vSAN traffic from other types of traffic (like vMotion, management, or VM traffic) using VLANs or separate physical networks.
  • If sharing network resources with other traffic types, use Quality of Service (QoS) policies to prioritize vSAN traffic.

7. Multicast (for vSAN 6.6 and earlier)

  • For vSAN versions 6.6 and earlier, ensure proper multicast support on physical switches. vSAN utilizes multicast for cluster metadata operations.
  • From vSAN 6.7 onwards, multicast is no longer required as it uses unicast.

8. Monitoring and Troubleshooting Tools

  • Regularly monitor network performance using tools like vRealize Operations, and ensure to troubleshoot any network issues promptly to avoid performance degradation.

9. VMkernel Network Configuration

  • Configure a dedicated VMkernel network adapter for vSAN on each host in the cluster.
  • Ensure that the vSAN VMkernel ports are correctly tagged for the vSAN traffic type.

10. Software and Firmware Compatibility

  • Keep network drivers and firmware up to date in accordance with VMware’s compatibility guide to ensure stability and performance.

11. Network Latency

  • Keep network latency as low as possible, particularly important in stretched cluster configurations.

12. Cluster Size and Scaling

  • Consider future scaling needs. A design that works for a small vSAN cluster may not be optimal as the cluster grows.

By following these best practices, you can ensure that your vSAN network is robust, performs well, and is resilient against failures, which is crucial for maintaining the overall health and performance of your vSAN environment.

Example 1: Small to Medium-Sized vSAN Cluster

  1. Network Speed: 10 GbE networking for all nodes in the cluster, especially beneficial for all-flash configurations.
  2. Physical Network Adapters:
    • Two dedicated 10 GbE NICs per ESXi host exclusively for vSAN traffic.
    • NIC teaming for redundancy using active-standby or LACP.
  3. Network Configuration:
    • Layer 2 networking with standard VLAN configuration.
    • Jumbo frames enabled to optimize large data transfers.
  4. Traffic Segmentation:
    • Separate VLAN for vSAN traffic.
    • VMkernel port group specifically tagged for vSAN.
  5. Cluster Size:
    • 4-6 ESXi hosts in the cluster, allowing for optimal performance without over-complicating the network design.

Example 2: Large Enterprise vSAN Deployment

  1. High-Speed Network Infrastructure:
    • Dual 25 GbE or higher network adapters per host.
    • Low-latency switches to support larger data throughput requirements.
  2. Redundancy and Load Balancing:
    • NIC teaming with LACP for load balancing and failover.
    • Redundant switch configuration to eliminate single points of failure.
  3. Layer 3 Networking:
    • For larger environments, Layer 3 networking might be preferable.
    • Proper routing setup to ensure low latency and efficient traffic flow between hosts, especially in stretched clusters.
  4. Advanced Traffic Management:
    • QoS policies to prioritize vSAN traffic.
    • Monitoring and management using tools like VMware vRealize Operations for network performance insights.
  5. Cluster Considerations:
    • Large clusters with 10 or more hosts, possibly in a stretched cluster configuration for higher availability.
    • Consideration for inter-site latency and bandwidth in stretched cluster scenarios.

Example 3: vSAN for Remote Office/Branch Office (ROBO)

  1. Network Configuration:
    • 1 GbE or 10 GbE networking, depending on performance needs and budget constraints.
    • At least two NICs per host dedicated to vSAN.
  2. Redundant Networking:
    • Active-standby configuration to provide network redundancy.
    • Simplified network topology suitable for smaller ROBO environments.
  3. vSAN Traffic Isolation:
    • VLAN segregation for vSAN traffic.
    • Jumbo frames if the network infrastructure supports it.
  4. Cluster Size:
    • Typically smaller clusters, 2-4 hosts.
    • Focus on simplicity and cost-effectiveness while ensuring data availability.