Category: VSAN

vSAN Network Design Best Practices

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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.

Handling Component Loss in VSAN

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In a vSAN environment, data is distributed across multiple hosts and disks for redundancy and fault tolerance. If some components are lost, vSAN employs various mechanisms to ensure data integrity and availability:

  1. Automatic Component Repair:
    • vSAN automatically repairs missing or degraded components when possible.
    • When a component (e.g., a disk or a host) fails, vSAN automatically starts rebuilding the missing components using available replicas.
  2. Fault Domains:
    • Fault domains are logical groupings of hosts and disks that provide data resiliency against larger failures, such as an entire rack or network segment going offline.
    • By defining fault domains properly, vSAN ensures that data replicas are distributed across different failure domains.
  3. Policy-Based Management:
    • Use vSAN storage policies to specify the level of redundancy and performance required for your VMs.
    • Policies dictate how many replicas to create, where to place them, and what to do in case of failures.
  4. Health Checks and Alerts:
    • Regularly monitor the vSAN cluster’s health using vSAN Health Check and other monitoring tools.
    • Address any alerts promptly to prevent further issues.
  5. Recovery from Complete Host Failure:
    • In the event of a complete host failure, VMs and their data remain accessible if enough replicas exist on surviving hosts.
    • Replace the failed host and vSAN automatically resyncs the data back to the new host.

Automatic Component Repair in vSAN is a critical feature that helps maintain data integrity and availability in case of component failures. When a component (such as a disk, a cache drive, or an entire host) fails, vSAN automatically initiates the process of rebuilding the affected components to restore data redundancy. Let’s understand how Automatic Component Repair works in vSAN with some examples:

Example 1: Disk Component Failure

  1. Initial Configuration:
    • Let’s assume we have a vSAN cluster with three hosts (Host A, Host B, and Host C) and a single VM with RAID-1 (Mirroring) vSAN storage policy, which means each data object has two replicas (copies).
  2. Normal Operation:
    • The VM’s data is distributed across the three hosts, with two replicas on different hosts to ensure redundancy.
  3. Disk Failure:
    • Suppose a disk on Host A fails, and it contains one of the replicas of the VM’s data.
  4. Automatic Component Repair:
    • As soon as the disk failure is detected, vSAN will automatically trigger a process to rebuild the lost replica.
    • The surviving replica on Host B will be used as the source to rebuild the missing replica on another healthy disk within the cluster, which could be on Host A or Host C.
  5. Recovery Completion:
    • Once the new replica is created on a different disk within the cluster, the VM’s data is fully protected again with two replicas.

Example 2: Host Failure

  1. Initial Configuration:
    • Similar to the previous example, we have a vSAN cluster with three hosts (Host A, Host B, and Host C) and a VM with RAID-1 vSAN storage policy.
  2. Normal Operation:
    • The VM’s data is distributed across the three hosts with two replicas for redundancy.
  3. Host Failure:
    • Let’s say Host B experiences a complete failure and goes offline.
  4. Automatic Component Repair:
    • As soon as vSAN detects the host failure, it will trigger a process to rebuild the lost replicas that were residing on Host B.
    • The replicas that were on Host B will be recreated on available disks in the cluster, such as on Host A or Host C.
  5. Recovery Completion:
    • Once the new replicas are created on the surviving hosts, the VM’s data is again fully protected with two replicas.

Automatic Component Repair ensures that vSAN maintains the desired level of data redundancy specified in the storage policy. The process of rebuilding components may take some time, depending on the size of the data and the available resources in the cluster. During the repair process, vSAN continues to operate in a degraded state, but data accessibility is maintained as long as the remaining replicas are available.

It’s important to note that vSAN Health Checks and monitoring tools can provide insights into the status of the cluster and any ongoing repair activities.

These tools assist in identifying potential issues, optimizing performance, and ensuring data integrity. Here are some essential vSAN monitoring tools:

  1. vSAN Health Check:
    • The vSAN Health Check is an integrated tool within the vSphere Web Client that provides a comprehensive health assessment of the vSAN environment.
    • It checks for potential issues, misconfigurations, or capacity problems and offers remediation steps.
    • You can access the vSAN Health Check from the vSphere Web Client by navigating to “Monitor” > “vSAN” > “Health.”
  2. Performance Service:
    • The vSAN Performance Service provides real-time performance metrics and statistics for vSAN clusters and individual VMs.
    • It allows you to monitor metrics like throughput, IOPS, latency, and other performance-related information.
    • You can access the vSAN Performance Service from the vSphere Web Client by navigating to “Monitor” > “vSAN” > “Performance.”
  3. vRealize Operations Manager (vROps):
    • vRealize Operations Manager is an advanced monitoring and analytics tool from VMware that provides comprehensive monitoring and capacity planning capabilities for vSAN environments.
    • It offers in-depth insights into performance, capacity, and health of the entire vSAN infrastructure.
    • vROps also provides customizable dashboards, alerting, and reporting features.
    • vRealize Operations Manager can be integrated with vCenter Server to get the vSAN-specific analytics and monitoring features.
  4. esxcli Commands:
    • ESXi hosts in the vSAN cluster can be monitored using various esxcli commands.
    • For example, you can use “esxcli vsan cluster get” to view cluster information, “esxcli vsan storage list” to check disk health, and “esxcli vsan debug perf get” to retrieve performance-related data.
  5. vSAN Observer:
    • The vSAN Observer is a tool that provides advanced performance monitoring and troubleshooting capabilities for vSAN clusters.
    • It collects detailed performance metrics and presents them in a user-friendly format.
    • The vSAN Observer can be accessed from an SSH session to the ESXi hosts, and you can run “vsan.observer” to initiate the collection.
  6. VMware Skyline Health Diagnostics for vSAN:
    • VMware Skyline is a proactive support technology that automatically analyzes vSAN environments for potential issues and sends recommendations to VMware Support.
    • It provides insights into vSAN configuration, hardware compatibility, and other relevant information to improve the health of the environment.

I personally use vSAN Observer a lot in my daily VSAN checks.

Accessing VSAN Observer: To use VSAN Observer, you need to access the ESXi host via an SSH session. SSH should be enabled on the ESXi host to use this tool. You can use tools like PuTTY (Windows) or the Terminal (macOS/Linux) to connect to the ESXi host.

  1. Start VSAN Observer: To initiate the VSAN Observer, run the following command on the ESXi host:
vsan.observer
  1. View VSAN Observer Output: After running the command, VSAN Observer starts collecting performance statistics and presents an output similar to the top command in a continuous mode. It updates the performance statistics at regular intervals.
  2. Navigating VSAN Observer: The VSAN Observer output consists of multiple sections, each displaying different performance metrics related to vSAN.
  • General Overview: The initial section provides a general overview of the vSAN cluster, including health status and disk capacity utilization.
  • Network: This section displays network-related performance metrics, such as throughput, packets, and errors.
  • Disk Groups: Information about each disk group in the cluster, including read and write latency, cache hit rate, and IOPS.
  • SSD: Performance statistics for the SSDs used in the disk groups.
  • HDD: Performance statistics for the HDDs used in the disk groups.
  • Virtual Machines: Performance metrics for individual VMs using vSAN storage.
  1. Navigating VSAN Observer Output: Use the arrow keys and other keyboard shortcuts to navigate through the different sections and information displayed by VSAN Observer.
  2. Exit VSAN Observer: To exit VSAN Observer, press “Ctrl + C” in the SSH session.

Example: Using VSAN Observer to Monitor Disk Group Performance:

Let’s use VSAN Observer to monitor the performance of disk groups in a vSAN cluster.

  1. Access the ESXi host via SSH.
  2. Start VSAN Observer by running the following command:
vsan.observer
  1. Navigate to the “Disk Groups” section using the arrow keys.
  2. Observe the performance metrics for each disk group, such as read and write latency, cache hit rate, and IOPS.
  3. Monitor the output for any anomalies or performance bottlenecks in the disk groups.
  4. To exit VSAN Observer, press “Ctrl + C” in the SSH session.

Troubleshooting vSAN components using PowerShell (PowerCLI)

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Troubleshooting vSAN components using PowerShell (PowerCLI) involves identifying and resolving issues related to vSAN objects, disk groups, and components. Here are some common vSAN component troubleshooting steps along with PowerShell examples:

Step 1: Connect to vCenter Server First, open PowerShell with PowerCLI and connect to the vCenter Server using the Connect-VIServer cmdlet. Replace Your_vCenter_Server, Your_Username, and Your_Password with appropriate values.

# Connect to vCenter Server
Connect-VIServer -Server Your_vCenter_Server -User Your_Username -Password Your_Password

Step 2: Check vSAN Cluster Status Verify the overall status of the vSAN cluster to ensure that it is healthy. The Get-Cluster cmdlet can be used to retrieve cluster information, including vSAN status.

# Get vSAN Cluster Status
$vsanCluster = Get-Cluster -Name Your_vSAN_Cluster_Name
$vsanCluster | Select Name, VsanEnabled, VsanHealth

Step 3: Check Disk Group Health Use the Get-VsanDiskGroup cmdlet to retrieve information about vSAN disk groups and verify their health status.

# Get vSAN Disk Groups and Health Status
$vsanDiskGroups = Get-VsanDiskGroup -Cluster $vsanCluster
$vsanDiskGroups | Select Name, State, Health

Step 4: Check Component Health Verify the health status of vSAN components using the Get-VsanComponent cmdlet.

# Get vSAN Components and Health Status
$vsanComponents = $vsanCluster | Get-VsanComponent
$vsanComponents | Select Uuid, IsActive, State, Owner

Step 5: Check vSAN Objects Health Retrieve vSAN object information and verify the health status of vSAN objects using the Get-VsanObject cmdlet.

# Get vSAN Objects and Health Status
$vsanObjects = $vsanCluster | Get-VsanObject
$vsanObjects | Select Uuid, Health, Components

Step 6: Check vSAN Disk Health Ensure that individual vSAN disks are in good health using the Get-VsanDisk cmdlet.

# Get vSAN Disks and Health Status
$vsanDisks = Get-VsanDisk -Cluster $vsanCluster
$vsanDisks | Select DeviceName, Health, IsSsd

Step 7: Check vSAN Datastore Status Verify the vSAN datastore status using the Get-Datastore cmdlet.

# Get vSAN Datastores and Health Status
$vsanDatastores = Get-Datastore -Location $vsanCluster
$vsanDatastores | Select Name, Type, CapacityGB, FreeSpaceGB, ExtensionData.Summary.VsanDatastoreConfigInfo.Enabled

Step 8: Check vSAN Events and Alerts Retrieve vSAN events and alerts to identify any potential issues.

# Get vSAN Events
$vsanEvents = Get-VIEvent -Entity $vsanCluster -MaxSamples 100 | Where-Object { $_.FullFormattedMessage -match "vSAN" }
$vsanEvents | Select CreatedTime, FullFormattedMessage

Step 9: Review vSAN Health Checks Inspect vSAN health checks to identify specific issues affecting vSAN components.

# Get vSAN Health Checks
$vsanHealthChecks = Get-VsanClusterHealth -Cluster $vsanCluster
$vsanHealthChecks | Select CheckId, Result, Message

Step 10: Disconnect from vCenter Server Finally, disconnect from the vCenter Server when you have completed troubleshooting.

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

These PowerShell examples demonstrate how to use PowerCLI cmdlets to retrieve important information about vSAN components and verify their health status. When troubleshooting vSAN, it’s essential to pay attention to health checks, events, and alerts to identify and resolve issues effectively. Always exercise caution and ensure you have appropriate permissions before running PowerShell scripts in a production environment.

Validate the components of VMware vSAN

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To validate the components of VMware vSAN (Virtual SAN) using PowerCLI (PowerShell module for VMware), you can use various PowerCLI cmdlets to retrieve information about vSAN objects, disk groups, and components. Here are some PowerShell scripts that demonstrate how to validate different components of vSAN:

1. Validate Disk Groups and Disk Information:

# Connect to vCenter Server
Connect-VIServer -Server Your_vCenter_Server -User Your_Username -Password Your_Password

# Get vSAN Disk Groups
$vsanDiskGroups = Get-VsanDiskGroup

# Display Disk Group Information
foreach ($diskGroup in $vsanDiskGroups) {
    Write-Host "Disk Group UUID: $($diskGroup.Uuid)"
    Write-Host "State: $($diskGroup.State)"
    Write-Host "Capacity: $($diskGroup.CapacityGB) GB"
    Write-Host "Used Capacity: $($diskGroup.UsedCapacityGB) GB"
    Write-Host "Number of Disks: $($diskGroup.Disks.Count)"
    Write-Host "-------------------------------------------"
}

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

2. Validate vSAN Components:

# Connect to vCenter Server
Connect-VIServer -Server Your_vCenter_Server -User Your_Username -Password Your_Password

# Get vSAN Cluster
$vsanCluster = Get-Cluster -Name Your_vSAN_Cluster_Name

# Get vSAN Component Information
$vsanComponents = $vsanCluster | Get-VsanComponent

# Display Component Information
foreach ($component in $vsanComponents) {
    Write-Host "Component UUID: $($component.Uuid)"
    Write-Host "Is Active: $($component.IsActive)"
    Write-Host "State: $($component.State)"
    Write-Host "Owner Host: $($component.Owner.Host)"
    Write-Host "Owner Disk: $($component.Owner.DeviceName)"
    Write-Host "-------------------------------------------"
}

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

3. Validate vSAN Objects and Health:

# Connect to vCenter Server
Connect-VIServer -Server Your_vCenter_Server -User Your_Username -Password Your_Password

# Get vSAN Cluster
$vsanCluster = Get-Cluster -Name Your_vSAN_Cluster_Name

# Get vSAN Object Information
$vsanObjects = $vsanCluster | Get-VsanObject

# Display Object Information
foreach ($vsanObject in $vsanObjects) {
    Write-Host "Object UUID: $($vsanObject.Uuid)"
    Write-Host "Health Status: $($vsanObject.Health.Status)"
    Write-Host "Component Count: $($vsanObject.Components.Count)"
    Write-Host "Owner: $($vsanObject.Owner.Name)"
    Write-Host "Type: $($vsanObject.ObjectType)"
    Write-Host "-------------------------------------------"
}

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

These scripts use PowerCLI cmdlets to connect to the vCenter Server, retrieve information about vSAN disk groups, components, and objects, and display their details. You can run these scripts on a machine with PowerCLI installed, and make sure to replace Your_vCenter_Server, Your_Username, Your_Password, and Your_vSAN_Cluster_Name with appropriate values.

Before running any scripts that interact with vCenter or vSAN, ensure you have the necessary permissions to access the vCenter environment. Always test scripts in a non-production environment first to ensure they behave as expected.

Troubleshooting with the vSAN Calculator

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Resolving Storage Capacity and Performance Issues Introduction: The vSAN Calculator is a powerful tool provided by VMware to assist in sizing and planning storage capacity and performance for vSAN deployments. While the calculator is primarily used for initial planning, it can also be a valuable resource for troubleshooting storage capacity and performance issues. In this guide, we will explore how to leverage the vSAN Calculator for troubleshooting, identify common issues, and provide practical solutions to optimize your vSAN environment.

Table of Contents:

1. Understanding the vSAN Calculator for Troubleshooting

a. Overview of the vSAN Calculator

b. How the calculator can aid in troubleshooting

c. The importance of accurate capacity and performance planning

2. Troubleshooting Storage Capacity Issues

a. Identifying inadequate storage capacity

b. Using the vSAN Calculator to assess capacity requirements

c. Adjusting capacity planning based on real-world usage

d. Implementing storage efficiency features (deduplication, compression) to optimize capacity

3. Troubleshooting Performance Issues

a. Identifying performance bottlenecks

b. Using the vSAN Calculator to evaluate workload requirements

c. Adjusting performance planning based on workload characteristics

d. Optimizing cache and capacity tiers for improved performance

4. Troubleshooting Disk Group Configuration

a. Understanding the impact of disk group configuration on performance

b. Analyzing disk group configurations using the vSAN Calculator

c. Adjusting disk group settings to optimize performance

d. Addressing common disk group issues (RAID levels, disk selection)

5. Troubleshooting Storage Policies

a. Assessing the impact of storage policies on capacity and performance

b. Using the vSAN Calculator to evaluate different storage policy configurations

c. Adjusting storage policies to meet specific workload requirements d. Troubleshooting storage policy conflicts and inconsistencies

6. Troubleshooting Network and Connectivity Issues

a. Identifying network-related performance issues

b. Assessing network bandwidth requirements using the vSAN Calculator

c. Optimizing network configuration for improved performance

d. Troubleshooting network connectivity problems

7. Troubleshooting Data Resiliency and Availability

a. Assessing data resiliency requirements using the vSAN Calculator

b. Troubleshooting issues related to data availability and protection

c. Adjusting data resiliency settings to optimize performance and capacity

d. Resolving common data resiliency issues (failed components, rebuild delays)

8. Best Practices for Troubleshooting with the vSAN Calculator

a. Regularly assess and update capacity and performance plans

b. Validate calculations with real-world testing and benchmarks

c. Leverage VMware support and community resources for troubleshooting d. Stay informed about updates and new features of the vSAN Calculator

9. Real-World Troubleshooting Scenarios

a. Troubleshooting performance degradation in a vSAN cluster

b. Resolving storage capacity issues in a growing vSAN environment

c. Addressing disk group configuration problems for improved performance

10. Conclusion

a. Recap of troubleshooting with the vSAN Calculator

b. Importance of accurate capacity and performance planning

c. Final thoughts and recommendations for vSAN troubleshooting Conclusion: The vSAN Calculator is not only a valuable tool for initial planning but also for troubleshooting storage capacity and performance issues in your vSAN environment. By utilizing the calculator to assess capacity requirements, evaluate performance needs, and adjust configurations based on real-world usage, administrators can effectively troubleshoot and optimize their vSAN deployments. With the best practices and real-world scenarios provided in this guide, you will be well-equipped to resolve storage capacity and performance issues using the vSAN Calculator.

Let’s consider a scenario where an organization is planning to deploy VMware vSAN in their environment.

They have the following workload requirements and specifications: – Number of ESXi hosts: 4 – Total usable capacity required: 20TB – Number of VMs: 50 – Average VM size: 200GB – Read-to-write ratio: 70:30 – IOPS per VM: 500 To use the vSAN Calculator, follow these steps:

1. Access the vSAN Calculator: – Go to the VMware vSAN Compatibility Guide website (https://www.vmware.com/resources/compatibility/search.php). – Search for “vSAN Calculator” and select the appropriate version.

2. Input Parameters and Configuration Options: – Select the number of hosts (4) and the desired vSAN version. – Input the usable capacity required (20TB) and choose the desired data resiliency level (e.g., RAID-1 mirroring). – Specify the average VM size (200GB) and the number of VMs (50). – Input the read-to-write ratio (70:30) and the IOPS per VM (500). – Select any additional options or features required, such as deduplication and compression.

3. Generate and Interpret the Results: – Click on the “Calculate” button to generate the results. – The vSAN Calculator will provide recommendations for the required cache capacity, capacity tier, and disk groups based on the given inputs. – Review the results to ensure they align with the workload requirements and specifications provided.

4. Adjustments and Optimization:

– If the results do not meet the desired requirements, you can make adjustments in the vSAN Calculator by modifying the input parameters.

– For example, you can increase the number of hosts, adjust the data resiliency level, or change the cache capacity to optimize performance and capacity.

By using the vSAN Calculator in this scenario, the organization may find that they require a cache capacity of 1.2TB, a capacity tier of 18TB, and a configuration of 2 disk groups with 2 drives per host.

Remember that the vSAN Calculator provides a starting point for sizing and planning, and it’s important to validate the results by conducting real-world tests and benchmarks. Additionally, regularly reassess and update your capacity and performance plans as workload requirements change over time.

Troubleshooting VSAN Objects and Components in VMware vSAN

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Introduction: VMware vSAN (Virtual SAN) is a software-defined storage solution that aggregates local storage devices across multiple hosts to create a shared datastore. vSAN introduces the concept of objects and components to manage data redundancy and availability. However, issues with vSAN objects and components can impact the performance, availability, and data integrity of a vSAN cluster. In this article, we will explore common troubleshooting techniques for vSAN objects and components in VMware vSAN.

1. Understanding vSAN Objects and Components: Before diving into troubleshooting, it is crucial to understand the concepts of vSAN objects and components. a. vSAN Objects:

– A vSAN object represents a virtual machine disk (VMDK), a virtual machine swap file, or a namespace file.

– vSAN objects are divided into fixed-size chunks called components, which are distributed across the vSAN cluster for redundancy and performance. b. vSAN Components:

– A vSAN component is a copy of a chunk of data that makes up a vSAN object.

– vSAN components are stored on multiple hosts in the vSAN cluster to provide redundancy and ensure data availability.

– Each component has a unique placement and is assigned a specific role, such as a primary or replica component.

2. Identifying vSAN Object and Component Issues: To troubleshoot vSAN object and component issues, it is crucial to identify the symptoms and potential causes. Some common indicators of issues include:

a. Performance degradation: – Slow read or write operations on vSAN objects.

– Increased latency for vSAN components.

– Decreased throughput or higher I/O latency. b. Data unavailability or loss: – Missing or inaccessible vSAN objects.

– Failed or absent vSAN components. – Inconsistent or corrupted data.

c. Cluster health alarms and events:

– vSphere alarms or events indicating vSAN object or component issues.

– Health checks reporting errors related to vSAN objects and components.

3. Troubleshooting vSAN Objects and Components: When troubleshooting vSAN objects and components, it is essential to follow a systematic approach. Here are some steps to help diagnose and resolve issues: a. Validate vSAN Cluster Health:

– Use the vSphere Web Client or vSAN Health Service to check the overall health of the vSAN cluster.

– Address any critical health alerts or warnings related to vSAN objects and components. b. Check vSAN Object and Component Health:

– Use the vSphere Web Client or vSAN Health Service to monitor the health of individual vSAN objects and components.

– Look for any errors, warnings, or inconsistencies in the vSAN object and component status.

c. Analyze Performance Metrics:

– Use vSphere performance monitoring tools, such as vCenter Server or vSAN Performance Service, to analyze performance metrics related to vSAN objects and components.

– Look for any abnormal latency, throughput, or IOPS patterns that could indicate performance issues.

d. Review vSAN Logs:

– Examine vSAN log files, such as the vSAN trace logs and vSAN Observer logs, to identify any error messages or warnings related to vSAN objects and components.

– Pay attention to log entries indicating failed or absent components, data checksum errors, or communication issues between hosts.

e. Verify Network Connectivity:

– Ensure that there are no network connectivity issues between hosts in the vSAN cluster.

– Check for any misconfigurations, network disruptions, or faulty network components that could impact vSAN object and component communication.

f. Check Disk and Host Health:

– Verify the health of the physical disks and hosts participating in the vSAN cluster.

– Look for any disk failures, disk latency issues, or host connectivity problems that could affect vSAN object and component operations.

g. Rebuild or Repair Components:

– If a vSAN component has failed or is absent, initiate a rebuild or repair operation to restore redundancy.

– Use the vSphere Web Client or vSAN Health Service to initiate the rebuild or repair process for the affected vSAN objects and components.

h. Monitor and Validate:

– After taking corrective actions, closely monitor the vSAN cluster, objects, and components to ensure that the issues are resolved.

– Validate the data integrity and availability of the vSAN objects and components by performing data integrity checks and recovery tests.

4. Engaging VMware Support: If you encounter persistent or complex issues with vSAN objects and components, it may be necessary to engage VMware Support. Provide them with detailed information about the symptoms, steps taken for troubleshooting, and any relevant log files or error messages. VMware Support can provide further guidance and assistance in resolving the issues.

Conclusion: Troubleshooting vSAN objects and components is crucial for maintaining the performance, availability, and data integrity of a vSAN cluster. By following a systematic approach and leveraging vSphere tools and logs, administrators can identify and resolve issues related to vSAN objects and components. Regular monitoring, proactive maintenance, and prompt action in addressing issues will ensure the optimal functioning of the vSAN environment and the successful management of data in VMware vSphere.

VSAN RAID Workflow: Understanding and Configuring RAID in VMware vSAN

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Introduction: VMware vSAN is a software-defined storage solution that allows organizations to create a distributed storage infrastructure using the local disks of their ESXi hosts. One of the key features of vSAN is its ability to provide data protection through the use of RAID (Redundant Array of Independent Disks) technology. In this article, we will explore the workflow of configuring RAID in vSAN, understand the different RAID levels available, and discuss best practices for implementing RAID in a vSAN environment.

1. Understanding RAID Levels: Before diving into the vSAN RAID workflow, it is important to understand the different RAID levels available in vSAN. VMware vSAN supports three RAID levels:

– RAID-1 (Mirroring): Data is mirrored across multiple disks, providing redundancy and improved read performance.

– RAID-5 (Erasure Coding): Data is distributed across multiple disks with parity information, providing both redundancy and increased storage capacity.

– RAID-6 (Erasure Coding): Similar to RAID-5, but with two parity disks for increased fault tolerance. Each RAID level offers a different balance between data protection, storage capacity, and performance. It is crucial to choose the appropriate RAID level based on the specific requirements of your environment.

2. vSAN RAID Workflow: The vSAN RAID configuration workflow involves several steps to configure and manage RAID settings. Let’s explore each step in detail:

a. Designing the vSAN Cluster: Before configuring RAID in vSAN, it is important to design the vSAN cluster properly. This includes selecting the appropriate number of hosts, determining the disk groups per host, and identifying the number of capacity and cache devices per disk group.

b. Enabling vSAN and Creating Disk Groups: Once the cluster is designed, enable vSAN on the ESXi hosts and create disk groups. Disk groups are logical containers that consist of one or more capacity devices and one cache device. In vSAN, RAID is implemented at the disk group level.

c. Choosing the RAID Level: After creating disk groups, determine the appropriate RAID level for each disk group. Consider factors such as data protection requirements, storage capacity, and performance needs.

d. Configuring RAID Level: Configure the desired RAID level for each disk group. This can be done using the vSphere Web Client or the vSphere Command-Line Interface (CLI). Specify the RAID level (e.g., RAID-1, RAID-5, RAID-6) and the number of failures to tolerate (FTT), which determines the level of redundancy.

e. Monitoring and Managing RAID: Regularly monitor the health and performance of the vSAN cluster to ensure the RAID configuration is functioning as expected. Use vSAN-specific monitoring tools, such as vSAN Health Service, to identify any issues related to RAID and take appropriate actions to resolve them.

f. Scaling and Expanding: As the storage requirements grow, it may be necessary to scale and expand the vSAN environment. This involves adding additional hosts or disks to the cluster. When expanding, consider the impact on the existing RAID configuration and ensure that the new disks are added to the appropriate disk groups with the desired RAID level.

3. Best Practices for vSAN RAID Configuration: To ensure optimal performance and data protection in a vSAN environment, it is important to follow best practices for RAID configuration. Here are some key recommendations:

a. Evaluate Data Protection Requirements: Understand the data protection requirements of your organization and select the appropriate RAID level accordingly. Consider factors such as the criticality of the data, recovery point objectives (RPOs), and recovery time objectives (RTOs).

b. Balance Between RAID Level and Storage Efficiency: Consider the trade-off between data protection and storage efficiency. RAID-1 provides higher redundancy but consumes more storage capacity compared to RAID-5 or RAID-6. Evaluate the storage efficiency requirements of your environment and choose the RAID level accordingly.

c. Distribute Disk Groups Across Hosts: To ensure fault tolerance and avoid a single point of failure, distribute disk groups across multiple hosts in the vSAN cluster. This provides redundancy and improves availability in case of host failures.

d. Regularly Monitor Health and Performance: Implement a monitoring strategy to regularly monitor the health and performance of the vSAN cluster. This includes monitoring RAID status, disk health, and storage utilization. This allows you to proactively identify any issues and take appropriate actions.

e. Plan for Future Growth: Consider future growth and scalability when configuring RAID in vSAN. Plan for additional disk groups and ensure that the cluster can accommodate future expansion without compromising performance or data protection.

Conclusion: Configuring RAID in a vSAN environment is a critical step in ensuring data protection and performance. By following the vSAN RAID workflow and adhering to best practices, organizations can achieve optimal storage efficiency, fault tolerance, and scalability. Understanding the different RAID levels available, designing the vSAN cluster appropriately, and regularly monitoring the health and performance of the environment are key factors in implementing a robust and reliable vSAN RAID configuration.

Reclaiming Space with SCSI Unmap

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vSAN 6.7 Update 1 and later supports SCSI UNMAP commands that enable you to reclaim storage space that is mapped to a deleted vSAN object.

Deleting or removing files frees space within the file system. This free space is mapped to a storage device until the file system releases or unmaps it. vSAN supports reclamation of free space, which is also called the unmap operation. You can free storage space in the vSAN datastore when you delete or migrate a VM, consolidate a snapshot, and so on.

Reclaiming storage space can provide higher host-to-flash I/O throughput and improve flash endurance.

vSAN also supports the SCSI UNMAP commands issued directly from a guest operating system to reclaim storage space. vSAN supports offline unmaps as well as inline unmaps. On Linux OS, offline unmaps are performed with the fstrim(8) command, and inline unmaps are performed when the mount -o discard command is used. On Windows OS, NTFS performs inline unmaps by default.

Unmap capability is disabled by default. To enable unmap on a vSAN cluster, use the following RVC command: vsan.unmap_support –enable

When you enable unmap on a vSAN cluster, you must power off and then power on all VMs. VMs must use virtual hardware version 13 or above to perform unmap operations.

Force Unmount temporary datastore used for vSAN traces from vSAN cluster ESXi hosts

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>> Disable vsantraced startup by running this command:

chkconfig vsantraced off

>> Stop the vsantraced service by running this command:

/etc/init.d/vsantraced stop

>> Change the syslog to point to the vSAN datastore .
>> Delete any coredump files that are present after checking that they are not required.
>> Sub Step to direct it to syslog :

If not planned or incorrectly configured, vSAN trace-level messages may be:
Taking up a lot of space on ESXi hosts running from a RAM disk
Written to non persistent storage

By default, vSAN traces are saved to /var/log/vsantraces. Default maximum file size is 180MB with rotation of 8 files.

By default, vSAN urgent traces are redirected through the ESXi syslog system. If an external syslog server is defined, the urgent traces are forwarded to the external collector.

Run this command to determine whether vSAN urgent traces are currently configured to                              redirect through syslog and log rotation settings:
# esxcli vsan trace get
You see output similar to:

VSAN Traces Directory: /vmfs/volumes/568ec568-06d68562-e655-001018ed2950/scratch/vsantraces
Number Of Files To Rotate: 8
Maximum Trace File Size: 180 MB
Log Urgent Traces To Syslog: true

Run this command to send urgent traces through syslog

# esxcli vsan trace set –logtosyslog true

To change the default settings, run with the desired parameter:

# esxcli vsan trace set

-l|–logtosyslog Boolean value to enable or disable logging urgent traces to syslog.
-f|–numfiles=<long> Log file rotation for vSAN trace files.
-p|–path=<str> Path to store vSAN trace files.
-r|–reset When set to true, reset defaults for vSAN trace files.
-s|–size=<long> Maximum size of vSAN trace files in MB.

For example, to reduce the number of files to rotate to 4 and maximum size to which these files can grow 200MB, run this command:

# esxcli vsan trace set -f 4 -s 200

Note: If you reduce the number of files, the older files that are not compliant are removed immediately.

>> Reboot the ESXi host.
>> Unmount the datastore.