There are many types of storage technologies that are gaining traction. Storage has greatly matured and progressed over the past few years. New and exciting technologies have come to the fore that are allowing organizations to provision, configure, and scale their storage environments for virtualization quickly and easily.

VMware is arguably the leader in enterprise datacenter virtualization today. They have pioneered several exciting new storage technologies that are providing powerful options for the enterprise. Two of these storage technologies are Virtual Volumes (VVOLs) and Virtual SAN (vSAN). Both offer exciting capabilities and opportunities for businesses to configure, manage, and scale their storage. While both VVOLs and vSAN have some similarities between them, they are different storage technologies.

VMware Virtual Volumes (VVOLs) are an advancement of the more traditional storage architecture that you are used to with a traditional SAN shared between VMware vSphere ESXi hosts. However, it incorporates new advancements in the way storage is presented to the ESXi hosts.

On the other hand, VMware’s software-defined storage solution is Virtual SAN or vSAN as it is branded now. VMware’s vSAN is an extremely powerful software-defined solution that has tremendous momentum and offers businesses truly next-generation capabilities in storage.

In this post, we will take a detailed look into both of these exciting technologies and see how each can help solve the storage challenges of today and tomorrow.

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VMware vSphere Virtual Volumes (VVOLs) Overview

VMware Virtual Volumes is aimed at changing the way more traditional storage solutions are provisioned in the VMware vSphere environments when using a storage area network (SAN) for storage.

What is VMware Virtual Volumes (VVOLs)?

At its heart, VMware vSphere Virtual Volumes is an integration and management framework for SAN and NAS that streamlines today’s storage operations. It does this through effective policy-driven automation that simplifies the delivery of storage to applications while at the same time providing more granular control of storage resources at the VM level instead of the traditional LUN level or storage unit. This helps to eliminate much of the overprovisioning that happens with traditional LUNs. The VM only consumes the amount of storage needed.

VMware Virtual Volumes is a new way that VMware is presenting storage to VMware vSphere ESXi hosts from traditional storage arrays. Now, with Virtual Volumes, each individual virtual machine and its disks are “objects” of storage and are presented as individual units of storage for VMware vSphere.

Each VMware VVOL object is presented as an individual storage entity as exported by a storage array that supports VVOLs storage provisioning.

How are these objects exported from the Storage Array and presented to the VMware vSphere ESXi hosts?

A special set of protocol endpoints (PE) are used to export the virtual volumes to the VMware vSphere ESXi hosts. These are used to create the data path between the VMs and the virtual volumes comprising their storage objects. The protocol endpoints are included as part of the physical storage fabric within the storage array.

You might wonder with virtual volumes creating several logical units of storage, this would be hard to manage? These can be grouped into constructs called storage containers (SC) that can be used for management. By combining the VMware vSphere Virtual Volumes themselves along with the storage containers, this forms the storage fabric for the virtual environment.

VMware Virtual Volumes make use of a special set of APIs that are known as the vSphere APIs for Storage Awareness or VASA for short. By using VASA, this is how storage is connected to the actual virtual machines from the underlying physical storage array.

One of the features of the VASA with virtual volumes is the communication between vSphere and the physical storage array can be used to offload many of the virtual machine operations to the physical storage array. These operations include such tasks as snapshots and clones.

The great thing about VMware VVOLs is that it continues to allow you to use familiar protocols for in-band communication with Virtual Volumes storage systems. This includes iSCSI and Fibre Channel as well as NFS storage area networks.

When using VMware vSphere Virtual Volumes, you create a VVOL Datastore to implement the technology. The VVOL datastore is a much different construct in ways than a traditional data store that may be formatted with a file system, etc. The VVOL datastore represents the underlying physical storage array along with the features present on the storage array. It provides provisioning limits, VM mappings, and storage policy service levels.

VMware vSphere Virtual Volumes Key Characteristics and Benefits

There are many key characteristics and benefits of VMware vSphere Virtual Volumes. Let’s talk about the following:

  • Virtualized Storage Consumption at the logical level
  • VMs become the primary focus of storage
  • Automated SLA Policy using SPBM
  • Improved Storage Management Operations
  • Storage Granularity
  • Flexibility in choosing Vendors for Storage

Let’s take a look at each of these key characteristics and benefits and see how each are accomplished using VMware vSphere Virtual Volumes.

Virtualized Storage Consumption at the Logical Level

VMware vSphere Virtual Volumes is a storage virtualization technology that abstracts the physical storage hardware resources. It does this by creating Virtual Volumes which are in effect logical pools of capacity that can be consumed in a flexible manner. They can span one or many storage arrays.

The Virtual Volumes datastore defines capacity, access, and data services accessible to the virtual machines that are found in the Virtual Volumes storage pool. Since Virtual Volumes are logical in nature, this means they can be configured spontaneously and without disruption that typically comes with reconfiguration of traditional storage arrays and technologies.

VMs Become the Primary Focus of Storage

Instead of in a traditional storage technology the LUN being the primary focus of storage, in VMware vSphere Virtual Volumes, the virtual machine itself becomes the centralized point of focus for storage.

Each Virtual Volume is a virtual disk container that is specific to the VM and totally independent of the physical storage. With this being said, the virtual machine virtual disk becomes the focus of data management at the array level.

With the focus and centralization of management at the virtual machine level, this means that execution of storage operations can be performed with VM-level granularity. With VMware vSphere Virtual Volumes, SLAs can be provided at the VM-level.

Automated SLA Policy using SPBM

VMware vSphere Storage Policy-Based Management or SPBM is well-known in the vSAN world. It is also available for use with VMware vSphere Virtual Volumes. It allows creating policy templates and then associate VMs to the policy template.

SPBM automates the provisioning of storage for virtual machines so the requirements defined in the SPBM policy including capacity, performance, available, etc, are met. With SPBM policy enforcement, monitoring and compliance throughout the lifecycle of the VM is easily achievable.

Improved Storage Management Operations

Simplified Operational Management is a key benefit to today’s fast paced virtual environments. VMware vSphere Virtual Volumes allows simplified storage management since it allows the vSphere administrator to be much more self-sufficient.

With traditional storage solutions, the virtual administrator may need to rely on the storage administrator for both the upfront storage provisioning for the virtual environment as well as any data services and service levels association with a virtual machine.

However, now with VMware vSphere Virtual Volumes, the vSphere administrator can be much more self-sufficient. The storage administrator may still need to provision the storage, but the vSphere administrator using the power of Virtual Volumes and SPBM can determine which data services should be assigned to a VM simply by selecting the policy needed with creating a particular VM.

So, this is no longer a physical storage construct to guarantee service level for the VMs, but rather is now a logical construct that can be automated. This enables a much more efficient, agile, and effective storage management and consumption for VMs.

Types of VVOL Objects

As mentioned earlier, VMware vSphere Virtual Volumes is an object-based storage technology. With that being said, the various components of the virtual machines are represented as objects in the VVOL datastore. There are several types of objects that comprise the underlying VVOL data structure for a VMware vSphere virtual machine. What are those?

  • Metadata – Config VVOL – This VVOL contains the settings, configuration and other information such as state information for the VMware vSphere virtual machine. This includes .vmx, .nvram, and any log files
  • VMDKs – Data VVOL – This is the virtual hard disk file for the virtual machine
  • Snapshots – Mem VVOL – This VVOL includes the memory information that is captured during a snapshot taken with memory
  • Swap files – Swap VVOL – Contains the virtual machine memory pages that are not included in memory
  • Vendor Solution Specific – Other VVOL – Vendor defined VVOL objects

VMware vSphere Virtual Volumes VVOLs Components

VMware vSphere Virtual Volumes is made possible by various storage components. Let’s take a look at those VVOL components. These include:

  • VVOL Datastore – This is not a file system but rather a representation of the storage array and its feature capabilities
  • Protocol Endpoints – A logical I/O proxy that communicates with VVOLs and VM disk files encapsulated by VVOLs. These are used by the ESXi host to establish a data path from VMs to their respective VVOLs
  • Data Path – The channel of communication between the VMware vSphere virtual machines and their respective virtual volumes
  • Storage Containers – These are not preconfigured volumes like are found in traditional storage, but rather it is a raw storage capacity or aggregate of storage capabilities of the storage array presented to vSphere
  • VASA Providers – These are VVOLs storage providers that makes up the software component that provides storage awareness to vSphere. The VASA providers are the “go-between” with the ESXi host and the storage system. The VASA providers are APIs
  • VVOLs Objects – Virtual Volumes are encapsulations of VM files, disks, and other components as objects. These objects are stored in storage containers on the array

VVOLs-vs-vSAN

A high-level overview of Virtual Volumes components (Image Courtesy of VMware)

How is VMware vSphere VVOLs Managed?

The great thing about VMware vSphere VVOLs is the workflow of vSphere administration to the vSphere administrator when working with virtual machines is the same. However, storage operations can be simplified with VVOLs as the storage provider. The storage administrator can configure the VVOLs datastore that presents the capacity and array-based features and then the vSphere administrator can then use these capabilities to control service levels.

Most management of VVOLs for the vSphere administrator will be providing and assigning Storage Policy-based Management (SPBM) policies. With SPBM policies the vSphere administrator can assign service levels very granularly to virtual machines running with VVOLs that can tier workloads based on specific array capabilities.

In essence, when you assign the SPBM policies to virtual machines, vSphere asks the storage array, “can you support this feature?”. This can be capacity or performance requirements. This requires no involvement from the storage administrator which means much more efficient and agile operations.

The management of storage is much simpler and more efficient since with VVOLs you don’t have to create separate datastores for different performance tiers or array capabilities. Below is a screenshot of creating a new storage policy and attaching to service levels with VVOLs.

VVOLs-vs-vSAN

Creating a new SPBM policy for VVOLs for service levels

VMware VVOLs Pros and Cons

VMware vSphere VVOLs provides really great new storage capabilities to today’s fast-paced virtualized environments. We have already touched on some of the benefits, however, let’s briefly look at the pros and cons of VMware vSphere VVOLs.

Pros

  • Simplifies and streamlines storage management
  • More efficient management of storage capacity and performance
  • Allows very granular control of VM performance with SPBM
  • Creates a logical construct for storage which allows more flexibility with storage container
  • Offloads snapshots and other functionality off to hardware storage array

Cons

  • Has had slow adoption among storage vendors which has led to slow adoption in enterprise
  • Needs to have support from backup solutions to support VVOLs
  • Relies on storage vendor more so on the capabilities and implementation rather than VMware. Some vendors are better than others with their code

VMware vSAN – Overview

VMware vSAN is a different approach to storage virtualization when compared to VVOLs.

With VMware vSAN, rather than using a physical vendor specific SAN, vSAN utilizes direct attached storage to the ESXi hosts in a vSphere cluster. VMware vSAN aggregates the DAS storage using a software-defined layer to present the storage as a single storage pool across all hosts in the vSAN-enabled vSphere cluster. This effectively eliminates the need for external shared storage and also simplifies storage configuration and VM provisioning.

VMware vSAN is fully integrated with VMware vSphere. In fact, vSAN is software that is actually included in the ESXi hypervisor itself.

When looking at the physical disk components that make up a VMware vSAN datastore, each ESXi host has two components to the vSAN datastore. Each host has a cache tier and a capacity tier for contributing to the vSAN datastore. Both are required.

The cache tier must be comprised of flash devices, while the capacity tier can be either traditional spindle magnetic storage or can also be flash-based.

VVOLs-vs-vSAN

Overview of vSAN Datastore architecture

VMware vSAN can also take advantage of the same Storage Policy-based Management (SPBM) templates that can be used with VVOLs. This helps to automate the service level of virtual machines down to the VMDK level.

Additional powerful vSAN configurations include two-node clusters for edge environments as well as stretched clustering that provides interesting configurations and opportunities for high availability.

Similarities Between VVOLs and vSAN

Customers looking at moving to a next-generation storage platform on their next refresh may be looking at both VMware vSphere VVOLs and vSAN. Which solution is best to choose?

It can be helpful to look at the similarities and differences between the two solutions to see where each solution shines. First, let’s take a look at the similarities between VVOLs and vSAN.

  • One of the first things that is strikingly similar between VVOLs and vSAN is they are both object-based storage. The virtual machine files are now represented as objects on both storage technologies. Object-based storage provides many benefits in efficiency and high availability features when compared to traditional storage configurations
  • Both technologies also simply the storage administration tasks that are normally involved with provisioning storage. With VVOLs, the vSphere administrator has much greater control over the storage solution with the more traditional storage array backing VVOLs. While the storage administrator has to provision the initial storage size and features, the vSphere administrator, using SPBM, has the ability to assign the service level for the virtual machines. This provides automation of virtual machine storage provisioning
  • Both technologies allow storage interaction and operations to be handled at the VMDK level which provides extreme granularity of the control, performance, and other characteristics of the virtual machine
  • Both vSAN and VVOLs allow you to have granular access to what is happening at the low-level of the virtual machine VMDK. This provides really great visibility that is not easily possible with traditional storage environments without difficulty

Differences Between VVOLs and vSAN

Let’s take a quick look at the differences between the two solutions. There are a few things to note between the two.

  • VMware vSAN uses locally attached storage to each ESXi host. VVOLs will be using a more traditional approach of having a SAN in place, however, abstracts the connections between the ESXi hosts and the storage array
  • When looking at getting VMware vSAN up and running, it doesn’t require any interaction with the storage administrator since everything can be done by the vSphere administrator with the locally attached storage to the ESXi host. With VVOLs, there will still need to be interaction with the storage administrator to provision the initial VVOLs datastore. From this perspective, vSAN will be simpler and more agile. However, VVOLs has greatly simplified the process once the storage administrator has provisioned the initial VVOls datastore
  • Another difference in VVOLs when compared to vSAN is the initial investment to get into the storage solution. While VVOLs requires a SAN with VVOLs technology capabilities to get started, vSAN requires only local storage. To get into a SAN, often these are “overscaled” initially to account for growth, etc
  • To scale vSAN, you simply add more hosts/disks in the future, so it is a bit simpler and perhaps more cost-effective to make use of vSAN. However, businesses that are already making use of SANs from a particular storage vendor may still lean towards VVOLs

How to Decide between VVOLs and vSAN

  • Between VVOLs and vSAN, it may depend on the storage technology that a business is aligned with. If your business currently uses and manages many SANs from a particular storage vendor, VVOLs may be a great transition while sticking with hardware configurations that are currently used. With greenfield installations, vSAN may be a great fit for organizations looking to delve into next generation software-defined storage that requires no external storage device and can be scaled as needed
  • If you are looking for a storage solution that requires no additional collaboration between departments and you want the vSphere administrator to be able to do everything that needs to be done to configure, provision, management, and maintain virtual machine storage, vSAN has the edge here
  • If you are looking for storage that is between traditional storage that is comfortable to many with a SAN and still is able to leverage next-generation features like SPBM, VVOLs can certainly deliver on that use case

Whichever storage solution your business decides to utilize, either VVOLs or vSAN are both great platforms to provide all the latest capabilities for production workloads and allow the vSphere administrator to have a great degree of control over the storage infrastructure.

Choose a Backup Vendor that Protects Both VVOLs and vSAN

Choosing a backup vendor is an extremely important decision because it has implications across the board for production virtual environments you may be running. Your backup solution will certainly dictate the technologies, versions, capabilities, and features that you are able to take advantage of. If you can’t back up the virtual machines running in a particular storage technology, you certainly will not be able to make use of it without reconsidering your backup solution. This can be expensive and certainly lead to a lack of agility in your environment.

When thinking about a backup vendor and the choice between VVOLs and vSAN, choose a backup vendor that is able to support both technologies. In this way, you are setting yourself up to be able to take advantage of either platform for storage.

Vembu BDR Suite is a great choice for businesses looking for a powerful, modern, backup vendor that is able to protect virtual machines running on both VVOLs and vSAN storage. It provides all the capabilities and features that you would expect from a next-generation backup solution protecting your workloads running in either storage platform.

When running on either VVOLs or vSAN datastores, Vembu BDR Suite is able to provide:

  • Automatic, seamless backups
  • Near continuous data protection for VMs running on VVOLs or vSAN datastores
  • Application-aware backups for protecting Microsoft SQL Server, Exchange
  • Server, SharePoint, and Active Directory

  • VM Replication
  • Offsite backup copies to align with the 3-2-1 backup best practice methodology
  • Backup encryption with encryption of your backup data both in-flight and at-rest
  • Support for the latest VMware platforms and versions

By choosing Vembu BDR Suite, you are not locked into either storage platform from VMware. You can decide to use one or both technologies and not have to worry about your backup solution getting in the way of taking advantage of next-generation features.

Concluding Thoughts

Both VVOLs and vSAN are exciting storage technologies that truly liberates the VMware vSphere environment from the underlying physical hardware. It does this by abstracting storage devices and presenting them in a logical format in a way that scales and provides the flexibility needed in today’s enterprise storage environments. Both have certain strengths and potential weaknesses mostly in the realm of use cases or best fit scenarios that may lend themselves to one technology over another.

An important decision with either technology is choosing a backup vendor that allows you to take advantage of either technology. This allows potentially picking one or both technologies now and then using a different technology in the future. Vembu BDR Suite is one such solution that enables you not to be tied to specific storage technology, but rather, keep your options open.

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