Since VMware’s acquisition of Virsto earlier this year, many customers and folks in the community have expressed a great deal of interest in the product. Since so many folks have requested more information about the product, I’ve decide to write a series of in-depth blog articles that will discuss VMware Virsto’s capabilities, benefits, and targeted use cases for the product. VMware Virsto is a software-defined storage solution design to optimize the use of external block storage in vSphere virtual infrastructures. VMware Virsto enhances the use of external Storage Area Networks (SAN) by accelerating performance and increasing overall storage utilization. When considering the storage challenges that are faced today in virtual infrastructures, one of the primary concerns revolves around performance and space efficiency. Virtualized environments tend to be performance intensive and persistent with the presentation of random I/O.
It is no secret that block based storage platforms work best with sequential I/O and VMware Virsto addresses the challenge which currently exists in virtualized infrastructures by intercepting all of the randomized I/O at the vSphere Hypervizor level and writing them to dedicated write logs in a serialized format and later de-staged onto virtual disks on storage area networks (SAN). As a result of this design the product improves performance by accelerating random I/O and also eliminating the disk-sprawl caused by performance constraints. This is all achieved regardless of what the underlying block based storage platform type or vendor may be.
VMware Virsto introduces a level of flexibility and elasticity for storage resources in similar way to how vSphere hypervizor provide compute resources for servers by effectively allowing all aspects of the storage constructs and resource characteristics such as performance, capacity, and a number of different data services like snapshots, clones, thin-provisioning, etc. to be completely defined in software. The product complements and leverages the vSphere rich portfolio of management tools and workflows to provide and deliver rapid provisioning of high performance capabilities and space-efficient storage solution.
The services and capabilities delivered by VMware Virsto are focused on a virtual machine centric management model from a storage perspective with much a more intuitive approach. The management of block-based storage (FC, iSCSI) is based on logical unit number (LUN) level which is both complex and inefficient in a world where the VM are the key object. A VM-centric storage management model is not only more efficient, but much easier to understand for vSphere administrators who do not have deep storage backgrounds.
VMware Virsto is designed to manage logical volumes presented to it by heterogeneous block based storage platforms, and because of this there is no need for the product to be responsible for managing disk devices directly. It is assumed that the existence of a reliable and highly available storage subsystem with adequate RAID designs and configuration are implemented before volumes are presented to VMware Virsto. VMware Virsto sits on top of the RAID layer, and it is able to see all the presented and connected storage as a set of volumes. Any of the underlying volumes might represent individual disk devices, some RAID aggregation of disks, or entire intelligent storage arrays. The underlying storage could be heterogeneous, exhibiting various qualities of service, or it could be a set of homogeneous block based storage devices.
In short, VMware’s Virsto is a true software-define storage solution for existing vSphere virtualized infrastructures. It delivers virtual machine centric I/O performance optimization and efficient and agile data services. In Part Two of this blog series, I will cover the VMware Virsto architecture and construct definitions. In subsequent articles I will map out specific use cases for the product, including Virtualized Database, Tier 2, and Tier 3 Test/Dev workloads stored on block based storage.
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