VVol Technical Overview

Another great session at PEX 2015 by Rawlinson Rivera.

Traditional storage architectures can’t keep up:

  • Specialized and costly HW – Not commodity, low utilization, overprovisioning
  • Device-centric silos – Static classes of service, rigid provisioning, lack of granular control
  • Complex processes – Lack of automation, time consuming processes, slow reaction to request

Hypervisor Enables App-Centric Storage Automation

  • Knows the needs of all apps in real time
  • Sits directly in the I/O path
  • Has global view of all underlying storage systems
  • Can configure storage dynamically
  • Hardware agnostic

Traditional Model – long provisioning cycles, managing LUNs, complex, frequent data migrations

App-Centric Automation – Dynamic delivery of storage services when needed. Fine control of data services at the VM level. Common management across heterogeneous devices.

vSphere Virtual Volumes

  • Virtualizes SAN and NAS devices
  • Virtual disks are natively represented on arrays
  • Enables VM granular storage operations using array-based data services
  • Storage policy-based management enables automated consumption at scale
  • Industry-wide initiative supported by major storage vendors
  • Included with vSphere

What is a VVol?

  • Five types of VVols (objects): Config, Data, MEM, SWAP, Other
  • NO filesystem needed (VMFS is history)
  • Virtual machine objects are stored natively on the array

Storage Container

  • Logical storage constructs for grouping of virtual volumes
  • Typically defined by storage administrators on the array in order to define storage capacity allocation and restrictions
  • Capacity is based on physical storage capacity

Differences between Storage Container and LUNs

  • SC Size based on array capacity
  • Max number of SCs depends on the array
  • Size of SC can be extended
  • LUNs need a filesystem, fixed size mandates more number of LUNs

Protocol End Points

  • Access points that enables communications between ESXi hosts and storage array systems
  • Scope of Protocol End Points: iSCSI, NFS v3, FC, FCoE
  • A protocol endpoint can support any one of the protocols at a given time
  • End points receive SCSI or NFS reads, write commands
  • Storage container – For large number of VMs metadata and data files

Management Plane

  • VASA Provider (VP) – Developed by storage array vendors
  • Single VASA provider can manage multiple arrays
  • VASA provider can be implemented within the array or as a virtual appliance
  • Out of band communications
  • ESX and vCenter server connect to VASA provider

Storage Capabilities and VM Storage Policies

  • Are array based features and data services specifications that capture storage requirements that can be satisified by a storage array’s advertised capabilities.
  • Storage array capabilities define what the array can offer to storage containers as opposed to what the VM requires
  • VM storage policies is a component of the storage policy based management framework (SPBM)
  • Published capability – Array based features and data services. Advertised to ESX through VASA APIs
  • Managed on a per vDisk basis
  • Has a concept of compliance to ensure service level is being met

Operations Scenarios

  • Can offload: VM provisioning, machine deletes, full clones, linked clones, snapshots
  • Snapshots: Managed by ESX OR managed by the array

Note: SRM will NOT support vVols in this release. You will need to wait for the next release for this support.

Q&A: Future VVols will allow storage pool to span physical arrays.

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July 5, 2017 4:33 am

Thanks Derek Seaman On the NetApp end, things don't change too much from the model today. One or more Vservers will present NFS volumes and/or target LUNs to vSphere. Each Vserver has 1 or more aggregates in which FlexVols can be created for NFS volumes or to host LUNs. The biggest difference is in the SAN architecture. The target LUNs seen by vSphere are proxies and many VVOL LUNs can be behind it. This gives us the ability to see and manage each VVOL LUN. Think Network proxies, but for LUNs. For NFS a VVOL is simply a file just… Read more »