WSFC Configuration with vSAN 6.7 iSCSI Target

In my previous post, I have discussed about iSCSI Target Configuration in vSAN 6.7 and mentioned about new feature Windows Server Failover Clusters (WSFC) using the vSAN iSCSI target service. In this post, you can find the configuration of Windows Server Failover Cluster with iSCSI target feature in Windows 2012 Virtual Machine .This Feature is supported with Physical Window Servers also .

vSAN 6.7 fully support transparent failover of LUNs with the iSCSI service for vSAN when used in conjunction with WSFC. With support of this feature, now customers no need to buy a storage array and it save lot of money.

Steps Involved in this Procedure

  • Enable iSCSI Initiator
  • Create iSCSI Initiator Group
  • Create iSCSI Target and LUN
  • Configure the iSCSI  Target on Servers
  • Windows Server Failover  Cluster Creation
  • Fail over Testing


Number of Servers  2 ( Based Licensee You can use more Hosts)
Network Card Each Node with 3
DNS Resolution Required
IP Each Server required  2 Public IP and 2 Heart Beat IP and 1 iSCSI IP
Cluster Name with FQDN Required
Windows Update Fully Updated -  Two nodes
Quorum  With Min 2 GB iSCSI disk
iSCSI Enabled on Both Servers
MPIO Feature Feature to be enabled with policy set to “Fail Over Only”


Windows Server Failover Clusters (WSFC)

A Windows Server Failover Cluster (WSFC) is a group of independent servers that work together to increase the availability of applications and services.

Components you must know in WSFC

Node – Node is referred as server that that is participating in a WSFC.

Cluster Resource -   It is a physical or logical entity that can be owned by a node, which you can perform actions as brought online, offline, move between nodes and managed as a cluster object. Cluster resource can be owned by a single node at any point of time.

Role  -  Role is a collection of cluster resources managed as a single cluster object to provide specific functionality. A role contains all the cluster resources that are required for a n Availability Group (AG) or Always On Failover Cluster Instance (FCI) and Failover and failback always act in context of roles. A role will contain an IP address resource, a network name resource, and resources for the role.

Network Name Resource  -  A logical server name that is managed as a cluster resource. A network name resource must be used with an IP address resource. These entries may require objects in Active Directory Domain Services and/or DNS.

Quorum  -   The quorum configuration in a failover cluster that determines the number of node failures that the cluster can sustain.

Enable iSCSI Initiator

Navigate t oServer Manager -> Tools -> Select iSCSI Initiator

It will enable iSCSI Initiator on the server

From the Configuration Tab Collect the Initiator Name , it is required while configuration access

Create iSCSI Initiator Group 

Navigate to Cluster ->Configure -> vSAN-> iSCSI Initiator Group

Provide a Name for Group and add the Initiator Name you have collected from servers to the members list .

Now you can see the available members in the group , this will help you to restrict the access to the lUN to these members only .

Create iSCSI Target and LUN

Cluster ->Configure -> vSAN-> iSCSI Targets -> Click  " +"  Add button and fill the required details click ok

Add the Alias , Selec the iSCSI VMK network , Storage Policy also from same window you have option to create a LUN

Here I am creating Quorum disk with LUN ID 5 and 3 Gb size

Click on Allowed Initiators Tab and add the Initiator Group

Configure the iSCSI  Target on Servers 

First Verify the iSCSI Network from Hosts Navigate to -> ESXi Host -> Configure -> Networking -> VMkernal Adapters

Open the iSCSI Initiator -> Discovery Tab  -> Click on Discover Portal and the iSCSI VMkernal IP

After adding move to Targets Tab and you can see the targets are available  with inactive state

Select each Target and click on Connect Option  , Select Enable multipath option and click OK

Go to Disk Managent and you can see the iSCSI LU is available , Now you can bring that disk online and create partition

Enable Fail Over Cluster Feature 

You have to enable this feature on all nodes which need to be part of WSFC

Navigate to Server Manager -> Manage -> Select Add Roles and Features 

Follow  the Screen Options as default and in Features Select  the Failover Clustering  -> Add features 

and on screen options , It will take while to finish the installation .

Windows Server Failover  Cluster Creation

After Enabling the Feature you have to create a Windows Cluster from Primary Server .

You have two option ,Validate Configuration and Create Cluster

Validate Configuration - Validating the Cluster Prerequisites are met , any Waring or error  on servers , any issue there you have to fix before proceeding and it is recommended to follow . Also after validating it will give option to create Cluster .

Create Cluster  - Starting the Cluster Creation with out Validating the server configuration and after creation of Cluster you can validate the configuration.

Proceed to Create Cluster with Screen Options

You have add both servers and Windows Custer IP and Name in required steps

Note - should not Select the Add eligible disk to Cluster Option 

After Finishing the Fail Over Cluster wizard  you can the see the New Cluster with added Node details .

Next You Can add the Configured iSCSI storage to the Cluster and configured required Roles

Navigate to Failover Cluster -> Storage ->Disks  and Select the Add disk Option

It will list the disk associated with with server and you can select the desired form there , and you can see the added disk on Disks

Configure a Quorum for the Cluster with added 3 GB Disk

Navigate to Cluster -> Right Click -> More Actions ->Select Configure Cluster Quorum Settings

Follow the Screen options and you can see the  available disk to add as Quorum , select the desired disk and continue to finish this .


You can see the details on Tab Assigned To , as Disk Witness Quorum

Select the Disk and you can test fail over with  the Move the storage options Best Possible Node or Select Node

Best Possible Node - Automatically Select the node and storage will be moved

Select Node -  it will pop up with available Cluster resource you can move

Also you can shutdown the active node and verify the fail over status by login to other node.

Now you can Create Required Rolw after adding required Disk ,example for Data base , File Server etc

Reference vSAN 6.7

Reference for SQL - Microsoft SQL Server 2014 on VMware VSAN 6 Hybrid

Refer Microsoft Site for more details on Fail Over Cluster

Performance Analyzer 4.9.1 by Opvizor Released

Opvizor has released their new version 4.9.1 of Performance Analyzer  . I already discussed about Performance Analyzer in my previous Blog Post , how this product will monitor and analyze your virtual environment deeply .

With this new release, they have enhanced the monitoring capability and new features support more products .New features included support of Cisco (Cisco UCS and Cisco HyperFlex) and NetApp Solidfire and added many new metrics to extend dashboards capability.

What' New with Performance Analyzer 4.9.1

  • Cisco Support

Cisco Unified Computing System (UCS) and Hyperflex are two of powerful data center Converged and Hyper Converged products in the market. With new release of Performance Analyzer Cisco UCS and Hyperflex are supported and it required an additional license. With this feature, you will be able to monitor Server capacity and performance, network utilization from UCS and Complete Capacity monitoring, utilization and Compression of Hyperflex Systems and more.

  • NetApp Solidfire support

With 4.9.1 version of Performance Analyzer has added support of NetApp Solidfire Array and to use this feature you have to buy additional license. And you will achieve monitoring including Capacity, Performance utilization ad read write and more

  • VMware vFlash configuration and performance metrics

As you know Flash Read Cache can accelerate virtual machine performance by using host-resident flash devices as a cache and now Performance Analyzer supported the monitoring of the vFlash configuration on the virtual environment.

  • VMware Horizon view support

Performance Analyzer supports VMware Horizon View sessions in PCoIP and Blast protocol also it will collect the performance data to monitor response time, data throughput and frames per second.

  •  Additional reporting feature, now you can export the dashboards to PDF format. automatic resizing for system disk
  • Workaround if vCenter and ESXi system times are mismatching
  • Updated VMware dashboards – extended description
  • New dashboards are available in this version , it included “Virtual Machines - Disksize”, “Starter: VMware Datastores”
  • Postgresql-based reports  are supported  including Inventory, Snapshot, Change Management , it required an additional license

Apart from new features Opvizor fixed the many bugs for more accurate information, below are the bug fixes includes this version.

  • NUMA-statistics collection skips infrastructure lower than VMware vSphere 6.0
  • allow “-” in VMware infrastructure-names
  • missing Performance-metrics showing as -1
  • Veeam data crawler was stopping under certain circumstances
  • relaxed data collection interval for Microsoft SQL
  • custom retentions UI was broken in some cases
  • relaxed config data collection (5 to 10 minutes interval)

Download the Opvizor Performance Analyzer 30 Days Free Trial


What's New With Vembu BDR Suite Free edition

Vembu is focusing more in to Small and Medium Businesses with a reasonable price to fulfil their all requirements. BDR suite v3.9.1 has three versions Free, Standard which is new with this release and Enterprise. In this post, I am going to discuss about the new free version of the Vembu BDR Suite v3.9.1.

For every Organization even if it is small, medium or large Data is very important. If they lose their data business will get impacted, so data protection is Critical one .Most of the SMB’s does not have data protection it’s because of many are not aware about the impact of data loss and many due to their limited budget.

Vembu offers a free solution that would address the needs backups for the organizations do not have a backup strategy. You can configure multiple backup and restore jobs, with no feature restriction for three VMs without the need of purchasing any license. The free edition of Vembu BDR Suite will work smoothly with a set of Critical features that are part other paid versions and the free version is free forever.

Vembu BDR free edition will be the right fit for your Small business, if you do not have a Backup and DR plan in place, let’s find what Vembu Free edition offers to protect the data for Business Continuity.

Unlimited Agentless backups

Vembu VMBackup is on the feature, which offers Agentless Backup solution to protect the VMware vSphere ESXi, vCenter VMs and Microsoft Hyper-V VMs. Vembu VMBackup uses VMware vStorage APIs (VADP) feature to perform the agentless backup and a proprietary driver along with the Microsoft VSS technology in Hyper-V

Agentless backup reduces the efforts involved in installing the agent on each VMs and Backup and recovery configurations are simple since they are directly performs from Vembu BDR Server Web Console. This Web Console is very user friendly and you can manage backup, recovery, storage and reporting from a single pane.

High Availability

Vembu achieve the high availability by providing Near CDP (Continuous Data Protection) with an RTO and RPO of less than 15 minutes .Recovery options available in VMBackup are quick enough to keep data centers up and running with minimal downtime with near zero data loss. Also you can recover the physical and virtual infrastructure on VMware, Hyper-V or KVM platforms using Vembu Quick VM Recovery feature from image-based backups.


Backup of your data always required but really backed up data secure, since backup is falling under Data Protection and data is transferring through network. Vembu Free Edition Offers encryption to Organization for secure the backing up data.You can create a custom password for backup jobs  that enables AES 256 bit encryption which encrypts the backup data .

This feature provides a second layer of protection to customers by preventing accidental deletion of data and authority of it .You can recover or delete the backup’s jobs only after providing their respective passwords of the backup jobs.


Vembu BDR provides built-in compression feature to save storage consumption. You will save lot of space on the storage by compression and data size is less compare to the actual size of data. Backed up data is compressed then stored on the BDR server due to this traffic and time take taken to transfer the data from the client to the server is decreases.

Application-aware Backup

Vembu BDR Free edition achieving application-aware backup using Microsoft’s Volume Shadow Copy Service (VSS). Vembu VMBackup provides deep VSS integration to deliver application aware backup to ensure skipping of applications in a non-consistent state.

Vembu BDR server makes sure that consistent backups for Microsoft Applications like Exchange, SharePoint, Active Directory and SQL. Also, have an additional option to truncate the transaction logs for MS Exchange and MS SQL.

How Vembu Ensure the Consistency?

Vembu BDR solution has feature to pauses or “quiesces” the disk I/O until the writers of the applications become stable and then process further backup. This is performed in two steps which is included snapshot creation of application and Volume Shadow Copy Service to allow volume backups to performed while applications on a system continue to write to the volumes

Initially, a VSS request will be triggered followed by which a consistent backup for applications is initiated by Microsoft VSS before initiating a snapshot for that application. And there are no unfinished transactions that remain uncopied to the application database

Changed Block Tracking (CBT)

CBT is the technology used in Vembu BDR to track modified data blocks details of a backed up virtual machine to provide efficient storage utilization. After every full backup CBT will do this process and it will reduce backup widow as well as the storage consumption by backing up only the changes instead of full backup.

  • VMBackup for VMware vSphere & vCenter used the VMware’s CBT to modified blocks for incremental backup.
  • Hyper-V using Vembu’s proprietary CBT for tracking backed up blocks and process an incremental backup.

Disk Management Mount

 This is an interesting functionality of Vembu BDR free edition, which helps the users to recover the data from the disks of the virtual machines. This is an efficient recovery feature in the Vembu VMBackup for VMware and Hyper-V to get the data restored in few seconds.

Backed up virtual machines disk is being mounted on the local Vembu BDR server and users can access the files and folders that are residing in it quickly.


Quick VM Recovery

Vembu BDR free edition has a wonder feature called Quick VM Recovery .It is an instant recovery method used at the time of an unexpected disaster happened, which helps to reduce the downtime. Vembu is capable of recovering backup data instantly on either VMware or Hyper-V directly from storage targets, which is still compressed and encrypted. Moreover, the changes that are made during the quick boot session are also tracked and stored in the backup repository that might be used at times of permanent recovery.

Supports Various Storage Devices

Vembu VMBackup for VMware and Hyper-V supports multiple storage devices of different file systems be it local drives, NAS, SAN, iSCSI, VSAN iSCSI Target, Tapes etc. And it is flexible configure these devices pooled into multiple storage pools as well , this will help admins to add new storage volume /device to the existing pool on the fly  if they run out of storage.

Start Downing and use the benefits of Vembu BDR free edition

Vembu BDR Suite Review

Vembu is a leading software provider in the market since 2002 and recognized in market for data protection solutions. Vembu has various products and cloud services for small and medium businesses, which is cost effective and very convenient for customers. Vembu is more focusing on service provider level and Data Centers of Small, Medium Businesses and Vembu have 60000+ clients in worldwide through 4000+ service providers.

In this review, I will share essentials features of BDR Suite that helps decision makers to understand more on Vembu BDR Suite. First let’s check what Vembu Offers for IT Organizations to protect their data. Vembu provides various solutions and products to IT Organizations at reasonable price. Find the below details

Vembu Solutions

Vembu offers various solutions for your Organization, find the below solution details which is reliable and cost effective.

Vembu Products

Vembu has various products for your Infrastructure, find the below product details which is very suitable for your requirements.

Vembu as released their latest version BDR Suite v3.9.1, which is available in three editions: Free, Standard and Enterprise. Prior to old versions Vembu had Standard Edition in this release, which focused on SMB’s with a reasonable price.
Vembu BDR Suite - Free Edition is suitable for both virtual environments like VMware, Hyper-V and also for physical environments. It is free forever and does not have major restrictions.

Vembu BDR Suite - Standard Edition is designed and priced in a way to deliver a simple and cost-effective data protection solution for the Small and Medium businesses running their business critical servers in the virtual environment of VMware & Hyper-V.

Also, Vembu offers a flat 50% discount with Vembu VMBackup for Small and Mid-sized businesses that sustain with environments upto 6 CPU sockets.

Vembu BDR Suite is a collection of software products for organization’s backup and disaster recovery requirements. Vembu BDR Suite protects the business data hosted in both physical and virtual environment and supports deployment in on-premise, offsite and Cloud location.

Vembu BDR Suite provides complete, hassle-free Backup and Disaster Recovery (DR) solution for both physical and virtual environments. Vembu has centralized monitoring and management portal, which makes customers to monitor and manage deployments very easy.

I will share the overview of what Vembu BDR suite offering

● Vembu VMBackup

VMBackup is a backup and disaster recovery solution for the virtualized data centers. It supports both the VMware vSphere and Microsoft Hyper-V environments. Vembu VMBackup includes Agentless Backup & Replication of VMware VMs, Host Level Hyper-V VM Backup, CBT enabled Incremental backup and application-aware backup processing. Also it support Cross Platform Migration , download the backed up files in different formats VHD, VHDX, VMDK, VMDK-FLAT and RAW, can be used for V2V and V2P .

● Vembu ImageBackup

Vembu ImageBackup is designed to protect the physical windows servers and endpoints to cater the data protection needs of businesses which are still running Physical windows machine in their IT environment. You can schedule backup in every 15 minute to get an RPO and support recovery less than RTO of 15 minutes. Bare-metal Recovery also possible with Vembu that supports restoration of an entire Windows system from scratch to same or new hardware using Vembu Recovery CD.

● Vembu NetworkBackup & Vembu OnlineBackup

Network Backup will protect all your critical data across file servers, application servers, and Windows, Linux, and Mac workstations. It has the capability to do backup of Exchange Server and Mailboxes, SQL, Sharepoint, Active Directory & Registry Backups, SystemState. Vembu has a MS Outlook plugin, which protects your Outlook data completely. In addition, Vembu has OnlineBackup Capability, which can perform same network backup operations, but the data is directly transferred and stored on the Vembu Cloud.

● Vembu OffsiteDR & Vembu CloudDR

Vembu OffsiteDR replicates the backed up data from the local backup server to the DR server. In case of any disaster and data loss in primary location, you can restore the replicated data from the OffsiteDR. This process is same like restoring the data from backup server and then the entire infrastructure can be rebuilt easily.

CloudDR offers same functionality of OffsiteDR, the only change is, instead of DR Local server the backup data will be transferred to Vembu Cloud. And, you can restore your data from anytime anywhere via the internet and the restored data can be downloaded to USB drive and shipped.

● Vembu SaaSBackup

SaaS Backup provides a secure cloud backup solution with different recovery options for Office 365 (including OneDrive) and Google Apps (now G Suite). It backs up the Mails, Drives, Calendar and Contacts of your Office 365 and Google Apps. Users can backup and recover their Google Apps data anytime and anywhere, it allows users to access their files without the need to restore to the user account.
You can check the detailed Product details on Vembu Product-datasheets

Why VMBackup?

Answer is very simple! If your data is on VM, we need a backup of that and as we know that most of the companies are running their business application and Infrastructure server’s top of VMware vSphere/Hyper-V environment to achieve the benefits like cost savings, minimal downtime, better resource distribution etc.
VMware has inbuilt snapshot functionality to backup the VMs, even if we say backup it is not a complete backup solution. Snapshots are just state of a virtual machine at any specific point in time can be preserved. Never keep the snapshot longer period since it will consume more storage as well as degrade the performance of VM. So we need proper backup solution to keep our data safe, secure to prevent a failure.

Why Vembu VMBackup?

Normally Backup solutions are more expensive and difficult to manage because most of the solutions focused on larger organization Level. But Vembu BDR Suite is very suitable for Small and Medium Business with all the relevant features. Vembu VMBackup is the most cost effective Backup and Disaster Recovery software, which offers Backup and Replication for VMware Platform and Host level Backup for Hyper-V VMs with a reasonable price.

Key Features

● Agentless VMware and Hyper-V Backup
● Host level Hyper-V Backup
● VM Replication for High Availability
● RPO and RTO less than 15 minutes
● CBT enabled incremental data
● Supports VMware vSphere version 4 to 6.5 which includes VMware Virtual Volumes and Virtual SAN
● Supports Backup of Hyper-V VMs on SMB and CSV
● Backup-level encryption
● Quick VM Recovery
● Application-Aware Image Backups
● Vembu HIVE File System, a File System of File Systems for efficient backup storage
● Vembu Universal Explorer for Microsoft Exchange, SQL, Active Directory and SharePoint

More Information is available on Vembu-VMBackup

Vembu ImageBackup

Vembu’s products and solutions has many common key features available with different backup types, you can explore those feature while you explore more with Vembu BDR Suite. Vembu ImageBackup supports image-level backup of Windows operating systems that includes Microsoft Windows 7 and above Microsoft Windows Server 2008 SP2 and above Microsoft Windows SBS 2008 & 2011

Key Features

Bare-metal Recovery (BMR)

Using Vembu Recovery CD, IT admins can restore the backed up Windows Servers and Workstations to the same or different hardware.

Vembu Virtual Drive

Instantly recover all the Windows Servers and Workstations running in ESXi host or Hyper-V server by mounting Vembu Virtual Drive as datastore using NFS share. It helps to recover the entire data center during major disaster

Vembu Explorer for Microsoft Exchange

Instantly restore Exchange user mailboxes, emails, contacts etc. without restoring entire Exchange server machine

Vembu Explorer for Microsoft SQL Server

Instantly restore SQL database and tables without restoring entire SQL server machine

Vembu Explorer for Microsoft SharePoint

Instantly restore SharePoint site connections and documents without restoring entire SharePoint server machine

Vembu Explorer for Microsoft Active Directory

Instantly restore Active Directory objects and GPOs etc. without restoring entire Active Directory server machine

Bandwidth Throttling

It enables the user to limit the bandwidth used by the backup process during data transfer. If you do not want to spend your entire bandwidth on backups, use this feature to control or limit the bandwidth.

More Information Available on Vembu ImageBackup

VMware vSphere Quick Boot with ESXi 6.7

With release of vSphere 6.7 many enhancement to existing features and new features came. One of the efficient feature vSphere Quick Boot is available and I will be discussing about this feature in this post.

vSphere Quick Boot is an innovation by VMware and this feature helps on restarting the ESXi hypervisor without rebooting underlying  physical host . Quick Boot eliminates the time-consuming device initialization and self-testing procedures shortening the time. Not only the reboot , Quick Boot supports patching and upgrades of vSphere hosts through vSphere Update Manager.

This functionality is only available for hosts that are running ESXi 6.7 with compatible Hardware .Even if your hardware is compatible with Quick Boot and you are running a legacy version of ESXi, this feature will not be available. If the system is incompatible with vSphere 6.7 Quick Boot, it will perform a regular reboot.

 Supported Hardware Platforms

Currently Dell and HP are the OEM hardware vendors supports this feature and you can find the supported servers details on below links

With vSphere 6.7 a built in script available to test the hardware compatibility with ESXi Quick Boot.

Script Path - /usr/lib/vmware/loadesx/bin/

Detailed Information available on VMware KB

Verify the Host Compatibility

Login to ESXi as root from putty or Console

Verify the ESXi version and run the script

Configure vSphere Quick Boot 

Configuring VMware ESXi 6.7 Quick Boot functionality must be done through VMware Flex client and Upgrades or Patching Can be done though HTML Client

Navigate to Home > Update Manager

Select the vCenter Server and navigate to Manage - >  Host/Cluster Settings

You can see Quick Boot is not enabled , Click on Edit button go to configuration option.

Select the Enable Quick Boot option by adding Tick on the box and Click OK

After Enabling  , Verify the Quick Boot Status  .








The Update Manager UI will present Quick Boot as an option for servers that support the feature, however for some servers this option will not be available and your host will perform regular reboot rather than a Quick Boot.

You may see this issue if:

  • Host platform is not supported.
  • Host is configured to use a TPM.
  • passthru devices configured for VMs on your host.
  • vmklinux drivers loaded on your host.
  • Other non-certified drivers loaded on your host
  • Quick Boot is disabled in the Update Manager UI.

More vSphere 6.7 Posts

Refer VMware Documentation for More details .

Vembu BDR Suite v3.9.1 Released

Vembu BDR Suite is a complete solution designed to protect organization critical data. Vembu announced their latest BDR Suite version 3.9.1, which include Standard Edition appropriate for small business (SMBs) at very affordable pricing.

Vembu BDR Suite v3.9.1 is now available in three editions: Free, Standard and Enterprise .Compare all available features between the versions from Vembu  and choose the solutions suit for your business needs.

Standard edition of Vembu BDR Suite supports unlimited VM backup, fast VM recovery, Instant file recovery, granular recovery and much more and using these features BDR will protect Organization entire virtual IT infrastructure. Some top features is missing with version but for a SMB’s this version suitable and fulfilling their requirement with an affordable price.

Additionally new Standard Edition also offers built-in compression, deduplication, and security features using AES-256 encryption algorithm.

Key Features of Vembu VM Backup Standard Edition

Vembu BDR Suite v3.9.1 edition released with significant enhancements and bug fixes to improve performance and availability.

Vembu Standard Edition Pricing

This time Vembu comprehensively validated the customer requirements and decided to offer features to fulfill SMB’s requirement at a reasonable price.

Pricing for Standard Edition of VMware Backup at $ 216/CPU-socket per annum. If you planning to add more servers soon or the requirement comes under 6 CPU sockets, Vembu offers an additional discount of 50% and you have great saving .You have to pay only $ 108/CPU-socket per annum.

The Standard Edition for Hyper-V Backup also has reasonable price $ 144/CPU-socket per annum. More over above-mentioned discount category is available here also, only $ 72/CPU-socket per annum.

More on pricing details visit Vembu Pricing

Download Vembu BDR Suite v3.9.1  and experience the best modern data protection for your environment.

Configure iSCSI target on vSAN 6 .7

As we know with vSAN 6.5, VMware released feature iSCSI Target and with new release of vSAN version 6.7, they have enhanced this feature. vSAN 6.7 now supports iSCSI target with SCSI Persistent Reservations for iSCSI shared disks. We can present the iSCSI-shared disks from vSAN to Virtual machines on the same vSAN cluster and officially support Microsoft WSFC “Windows Server Failover Clusters “. In this post, I will cover how to configure iSCSI target on vSAN 6.7 environment and about WSFC will discuss on another post as continuation of this .

iSCSI target service will support to enable the hosts and physical workloads that reside outside the vSAN cluster to access the vSAN datastore.This feature enables an iSCSI initiator on a remote host to transport block-level data to an iSCSI target on a storage device in the vSANcluster.

After you configure the vSAN iSCSI target service, you can discover the vSAN iSCSI targets from a remote host. To discover vSAN iSCSI targets, use the IP address of any host in the vSAN cluster, and the TCP port of the iSCSI target. To ensure high availability of the vSANiSCSI target, configure multipath support for your iSCSI application. You can use the IP addresses of two or more hosts to configure the multipath.

Note:- vSAN iSCSI target service does not support other vSphere or ESXi clients or initiators, third-party hypervisors, or migrations using raw device mapping (RDMs).

How to Enable iSCSI Target

First verify iSCSI Target service status by following below , by default this service will be disabled

Navigate to the vSAN cluster - > Configure -> vSAN -> iSCSI Target Service 

Click on the Enable Option  , new window will appear with enable vSAN option

Enable the iSCSI target service  and add required details and Click Apply

You have to select the default network , TCP port, Authentication method and a vSAN Storage Policy.

You Can monitor the progress on the recent tasks

Once the Target service is enabled you will the options to configure the iSCSI Targets and do other related configurations

create an iSCSI target

Click on " + "  Add button  to create new iSCSI target and  from same window you can create the LUN and assign to the same target or you can skip this potion by remove the " tick "  , you can use the vSphere Flex Client to do these configuration .

While creating iSCSI Target and LUN  you have to fill various details

  • VMKernel Interface
  • iSCSI target Alias name
  • TCP Port Number
  • Authentication Method (CHAP and Mutual CHAP supported)
  • The Storage Policy to be applied to the iSCSI Target
  • LUN ID
  • Alias for LUN
  • Size of the LUN
  • LUN ID
  • Storage Policy vSAN storage allocation for LUN , it gives you an example on the right hand side of what this looks like from a vSAN Perspective


After you create iSCSI target and LUN you will see similar configuration  like below

You have Option to configure the access to iSCSI target , you may specify the IQNs / Add them to Group or Everyone

Additionally you can configure iSCSI initiator Groups to manage  access to Targets

Navigate to vSAN Cluster->Configure ->vSAN -> iSCSI Initiator Groups to configure .

From a vSAN side iSCSI Target configuration and LUN maping has been completed, now you can login to Windows Machine  configure the iSCSI Initiator  .

Navigate to Administrative Tools -> iSCSI Initiator service -> Discovery Tab

and enter the IP Address of your iSCSI Target, my scenario host 1 and iSCSI IP is

If you are using CHAP/Mutual CHAP you can configure that also in advanced setting

After adding the IP of iSCSI target , Click on the “Targets” tab and you  will find Target IQN as “Inactive”, click on Connect and select “Enable Multi Path” also .


Another main thing if you need MPIO for iSCSI, this has to enabled if it is not listed under "Administrative Tools" ,you can enable the feature from Server Manager -> Add Roles and Features

If MPIO is enabled make sure you have selected “Add support for iSCSI devices” , if you enable this a Reboot is required for Windows Machine . Also need to add another path ( ip of vmk of another host in vSAN cluster  ) .

And you can configure the MPIO policy from -> iSCSI Targets -> Properties - > MCS / devices options

After adding the of  iSCSI target and enable MPIO you will be able see the devices from device manager and you can enable and configure the new iSCSI disk on windows .

Navigate to Computer Management ->Disk Management , you will see newly added un-partitioned disk in offline mode .

You can Change to Online Mode -> Initialize ->Format and start using the disk .


Additional Information 


In CHAP authentication, the target authenticates the initiator, but the initiator does not authenticate the target.

Mutual CHAP

In mutual CHAP authentication, an extra level of security enables the initiator to authenticate the target.

iSCSI Targets

You can add one or more iSCSI targets that provide storage blocks as logical unit numbers (LUNs). vSAN identifies each iSCSI target by a unique iSCSI qualified Name (IQN). You can use the IQN to present the iSCSI target to a remote iSCSI initiator so that the initiator can access the LUN of the target.

Each iSCSI target contains one or more LUNs. You define the size of each LUN, assign a vSAN storage policy to each LUN, and enable the iSCSI target service on a vSAN cluster. You can configure a storage policy to use as the default policy for the home object of the vSAN iSCSI target service.

iSCSI Initiator Groups

You can define a group of iSCSI initiators that have access to a specified iSCSI target. The iSCSI initiator group restricts access to only those initiators that are members of the group. If you do not define an iSCSI initiator or initiator group, then each target is accessible to all iSCSI initiators.

A unique name identifies each iSCSI initiator group. You can add one or more iSCSI initiators as members of the group. Use the IQN of the initiator as the member initiator name.


Recommended to read the iSCSI Target Configuration from VMware Library  and iSCSI target usage guide for more information about using the vSAN iSCSI target service


vSAN Erasure Coding – RAID 5 and RAID 6

First when you hear the term “Erasure Coding”, confused? , Let’s clarify this. what is “Erasure Coding” , Erasure Coding is a general term that refers to *any* scheme of encoding and partitioning data into fragments in a way that allows you to recover the original data even if some fragments are missing. Any such scheme is refer to as an “erasure code”  , this clarified from VMware Blog .

RAID-5 and RAID-6 are introduced in vSAN to reduce the overhead when configuring virtual machines to tolerate failures. This feature is also termed “erasure coding”. RAID 5 or RAID 6 erasure coding is a policy attribute that you can apply to virtual machine components. They are available only for all-flash vSAN Cluster, and you cannot use it on hybrid configuration.


To configure RAID-5 or RAID-6 on VSAN has specific requirement on the number of hosts in vSAN Cluster. For RAID-5, a minimum of 4 hosts and for RAID-6 a minimum of 6. Data blocks are placing across the storage on each host along with a parity. Here there is no dedicated disk allocated or storing the parity, it uses distributed parity. RAID-5 and RAID-6 are fully supported with the new deduplication and compression mechanisms in vSAN .

RAID-5  - 3+1 configuration, 3 data fragments and 1 parity fragment per stripe.

RAID-6  -  4+2 configuration, 4 data fragments, 1 parity and 1 additional syndrome per stripe.

To Learn More on RAID Levels , Check  STANDARD RAID LEVELS

You can use RAID 5 or RAID 6 erasure coding to protect against data loss and increase storage efficiency. Erasure coding can provide the same level of data protection as mirroring (RAID 1), while using less storage capacity.

RAID 5 or RAID 6 erasure coding enables vSAN to tolerate the failure of up to two capacity devices in the datastore. You can configure RAID 5 on all-flash clusters with four or more fault domains. You can configure RAID 5 or RAID 6 on all-flash clusters with six or more fault domains.

RAID 5 or RAID 6 erasure coding requires less additional capacity to protect your data than RAID 1 mirroring. For example, a VM protected by a Primary level of failures to tolerate value of 1 with RAID 1 requires twice the virtual disk size, but with RAID 5 it requires 1.33 times the virtual disk size. The following table shows a general comparison between RAID 1 and RAID 5 or RAID 6.

RAID Configuration Primary level of Failures to Tolerate Data Size Capacity Required

RAID 1 (mirroring)


100 GB

200 GB

RAID 5 or RAID 6 (erasure coding) with four fault domains


100 GB

133 GB

RAID 1 (mirroring)


100 GB

300 GB

RAID 5 or RAID 6 (erasure coding) with six fault domains


100 GB

150 GB

RAID-5/6 (Erasure Coding) is configured as a storage policy rule and can be applied to individual virtual disks or an entire virtual machine. Note that the failure tolerance method in the rule set must be set to RAID5/6 (Erasure Coding).

Additionally In a vSAN stretched cluster, the Failure tolerance method of RAID-5/6 (Erasure Coding) - Capacity applies only to the Secondary level of failures to tolerate .

RAID 5 or RAID 6 Design Considerations

  • RAID 5 or RAID 6 erasure coding is available only on all-flash disk groups.
  • On-disk format version 3.0 or later is required to support RAID 5 or RAID 6.
  • You must have a valid license to enable RAID 5/6 on a cluster.
  • You can achieve additional space savings by enabling deduplication and compression on the vSAN cluster..

RAID-1 (Mirroring) vs RAID-5/6 (Erasure Coding).

RAID-1 (Mirroring) in Virtual SAN employs a 2n+1 host or fault domain algorithm, where n is the number of failures to tolerate. RAID-5/6 (Erasure Coding) in Virtual SAN employs a 3+1 or 4+2 host or fault domain requirement, depending on 1 or 2 failures to tolerate respectively. RAID-5/6 (Erasure Coding) does not support 3 failures to tolerate.


Erasure coding will provide capacity savings over mirroring, but  erasure coding requires additional overhead. As I mentioned above erasure coding is only supported in all-flash Virtual SAN configuration and effects to latency and IOPS are negligible due to the inherent performance of flash devices.

Overhead on Write & Rebuild  Operations

Overhead on Erasure coding  in vSAN is not similar to RAID 5/6 in traditional disk arrays. When anew data block is
written to vSAN, it is sliced up, and distributed to each of the components along with additional parity information. Writing the data in distributed manner along with the parity will consume more computing resource  and write latency also increase since whole objects will be distributed across all hosts on the vSAN Cluster .

All the data blocks need to be verified and rewritten with each new write  , also it is necessary to have a uniform distribution of data and parity  for failure toleration and rebuild process  . Writes essentially are a sequence of read and modify, along with recalculation and rewrite of parity. This write overhead occurs during normal operation, and is also present during rebuild operations. As a result, erasure coding rebuild operations will take longer, and require more resources to complete than mirroring.

RAID-5  & Raid 6  conversion to/from RAID-1

To convert from a mirroring failure tolerance method, first you have to check  vSAN cluster meets the minimum host or fault domain requirement. Online conversion process adds additional overhead of existing components when you apply the policy. Always it is recommended do a test to convert virtual machines or their objects before performing this on production , it will help you to understand the impact of process and accordingly you can plan for production .

Because RAID-5/6 (Erasure Coding) offers guaranteed capacity savings over RAID-1 (Mirroring), any workload is going to see a reduced data footprint. It is importing to consider the impact of erasure coding versus mirroring in particular to performance, and whether the space savings is worth the potential impact to performance. Also you can refer below VMware recommendations .


  • Applications that are particularly sensitive to higher latencies and/or a reduction in IOPS such as ERP systems and OLTP applications should be thoroughly tested prior to production implementation.
  • Generally, read performance will see less of an impact from erasure coding than writes. Virtual SAN will first try to fulfill a read request from the client cache, which resides in host memory. If the data is not available in the client cache, the capacity tier of Virtual SAN is queried. Reads that come from the Virtual SAN capacity tier will generate a slight amount of resource overhead as the data is recomposed.
  • Workloads such as backups, with many simultaneous reads, could see better read performance when erasure coding is used in conjunction with larger stripe count rule in place. This is due to additional read locations, combined with a larger overall combined read IOPS capability. Larger clusters with more hosts and more disk groups can also lessen the perceived overhead.
  •  Ways to potentially mitigate the effects of the write overhead of erasure coding could include increasing bandwidth between hosts, use of capacity devices that are faster, and using larger/more queue depths. Larger network throughput would allow more data to be moved between hosts and remove the network as a bottleneck.
  • Faster capacity devices, capable of larger write IOPS performance, would reduce the amount of time to handle writes. Additional queue depth space through the use of controllers with larger queue depths, or using multiple controllers, would reduce the likelihood of contention within a host during these operations.
  • It is also important to consider that a cluster containing only the minimum number of hosts will not allow for in-place rebuilds during the loss of a host. To support in-place rebuilds, an additional host should be added to the minimum number of hosts.
  • It is a common practice to mirror log disks and place configure data disks for RAID5 in database workloads. Because Erasure Coding is a Storage Policy, it can be independently applied to different virtual machine objects, providing simplicity & flexibility to configuring database workloads.

vSAN Deduplication and Compression

Deduplication and compression are the two great space efficiency features on vSAN. With help of these techniques, you will be able to reduce the overall storage consumption on Virtual SAN. As we all know the concept of the duplication since it is been in use from long time by multiple storage and backup  vendors, so here I am not going explain more about that but just a brief on that and how vSAN uses this features .

First, you have to understand deduplication and Compression will work with only vSAN cluster with all flash mode ( Cache and Capacity Devices ) . vSAN keep most referenced data blocks in the cache tier while it is active/hot and as soon as the data is no longer active, it is moved to the capacity tier and during this movement vSAN does the deduplication and compression.

Deduplication and compression processing will occur only the data block is cold (no longer used) and it moved to the capacity tier. Advantage of this process is applications are writing data (same block) or over-written multiple times in the cache tier not on the Capacity Tier and there will not be any overhead on deduplication and compression.

Pic 1


If a block of data is already available on storage, a small reference will create to the existing block instead of writing the whole block again.

VSAN uses the SHA-1 hashing algorithm for deduplication, creates a “fingerprint” for each data block. This algorithm ensure that all data blocks uniquely hashed and multiple same data blocks will not be available on same hash. When a new data block comes in it will hashed and compared to the existing table of hashes. If the data block already available vSAN will add a new reference to it, if the block is not available, a new hash entry will create and the block is persisted.


This will help to squeeze more blocks to same footprint, VSAN uses the LZ4 compression mechanism and it works on 4KB blocks and get the 4KB block compressed to a size of 2KB.

If a new block found as unique it will go through compression. LZ4 compression mechanism reduce the size of the block to less than or equal to 2KB and compressed version of the block is continued to the capacity tier. If compression cannot reduce the size to less than 2KB, then the full-sized block is remain unchanged.

Deduplication and Compression Points

  • vSAN cluster must be on all flash ( Cache and Capacity devices ) .
  • You should enable together, Cannot enable each separately.
  • You must enable this on a group within disks on the same disks group.
  • Sha1 hash algorithm used for deduplication.
  • LZ4 is the compression mechanism used for compression.
  • Deduplication performed on 4KB block level.
  • vSAN will compress the deduped 4KB block down below 2KB or less , If not Original size remain same .
  • Single device failures will make the entire disk group appear unhealthy.
  • Deduplication and Compression will performed at the disk group level.
  • Deduplication is an IO intensive operation and more operations performed during destaging.

How Read and Write Operations on Duplication IO Intensity

As I mentioned above deduplication is an IO intensive operation, more operations are performed during the destaging of the data blocks.

Read – While performs a read, extra reads need to be sent to the capacity SSD in order to find the logical addresses and to find the physical capacity (SSD) address .

Write – During destage process, extra writes are required for perform the Hashing the data blocks from cache tier. The hot data on cache tier and hash map tables helps to reduce overheads. Therefore, this overhead has to be accounted, as this is the cause due to the 4KB block is been used.

Refer VMware Docs for More 

How to Obtain Free Version Of vSphere (ESXi) 6.7

VMware vSphere 6.7 has been announced by VMware recently and there are many enhancement and new features are available with this release. Question is how we can obtain a free version of vSphere 6.7 for our non-production or testing environment.

As earlier how we used to get free license for older versions same method we have the options to generate vSphere 6.7 license. License key with no expiration date can created free at VMware's website. You can use the "Free Hypervisor" as identical to the paid version but with some software limitations.

Also Free version has some technical  Spec and limitations , find the below .

  • Free ESXi cannot be added to a vCenter Server
  • No commercial support
  • Some API functionality is missing
  • Number of logical CPUs per host: 480
  • No physical CPU limitation
  • Maximum vCPUs per virtual machine: 8
  • If you have already a free key for ESXi 6.0 or 6.5, you can use the old key for vSphere 6.7 also.

How to Obtain Free vSphere License

  1. Browse to VMware vSphere Hypervisor (ESXi) 6.7 Download Page

  1. You can Login with existing account or create an account
  1. To Register for ESXi you have to enter your personal information .After registration, you will receive a unique license key and access to the vSphere 6.7 binaries.

  1. Now Download VMware vSphere Hypervisor 6.7 - Binaries

  1. You can install ESXi to your Hardware and ass the License to the ESXI host from web Client
  2. Login as root with the Embedded Host Client (https://<ESX IP / FQDN>/ui/)

5.Navigate to Manage -> Licensing

6. Click Assign license and enter your license key and start using the free vSphere  6.7