Pros & Cons of vSphere Virtual Storage Appliance

vSphere Virtual Storage Appliance [VSA]:

VSA is created for SMBs that either don’t have the budget to buy shared storage hardware or lack the skills to manage a more complex storage environment.

Without access to a SAN or NAS array, SMB aren’t able to use top features which are available in VMware virtual infrastructure like HA and vMotion etc.

pros-cons-of-vsphere-virtual-storage-appliance

With the help of VSA, SMB can now use many vSphere features without having to purchase a SAN or NAS device to provide them with shared storage.

Calsoft Whitepaper: File Virtualization with the Direct NFS Protocol

This paper discusses a SANergy-like file system that works on UNIX clients against UNIX servers using NFS, and provides the performance of a SAN, and the manageability of NAS. This paper was published at the NASA/IEEE Symposium on Mass Storage Systems, Maryland.

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VSA works by using the hard drives from the server hosts (ESXi or ESX servers) into a pooled storage, which is fault tolerant similar to an accumulative RAID device. If a single hard drive fails in a host, the RAID configuration within that host will keep providing the data. VSA mirrors data among multiple nodes (multiple ESXi or ESX server hosts). If a server fails, data contained in it will still be available from the hard drives of other ESX servers being used in the VSA configuration.

Pros of VSA

  • vMotion
  • svMotion [Storage vMotion]
  • DRS [Distributed Resource Scheduling ]
  • HA[High Availability]
  • Some vendors provide full functionality of a high-end SAN system
  • Saving in CAPEX
  • Saving in OPEX

Cons of VSA

  • A VSA doesn’t support memory over commit
  • VSA, once installed, restricts including additional storage to a VSA cluster
  • The VSA creates a usable partition that is equivalent to the amount of disk space in the server containing the least quantity of disk space
  • A VSA isn’t intended to be installed onto existing ESXi hosts; it prefers installation onto essentially un-configured hardware. ESXi hosts can’t run VMs before creating the VSA cluster
  • A VSA, in combination with VMware’s RAID requirements for locally attached storage, requires a 75 percent storage overhead for redundancy. This requirement means only 25 percent of deployed storage is actually available for use
  • A VSA can be configured in a 2 or 3 server configuration that, once installed, can’t be altered
  • VMware suggests one doesn’t run vCenter Server within VSA as a VM because the loss of a data store could prevent access to the VSA Manager. As a result, an additional and separate physical computer or VM is required to run vCenter Server and the VSA Manager.
  • A VSA reserves 33 percent of CPU and memory resources on a 3 hosts cluster and 50 percent of CPU and memory resources on a 2 hosts cluster for high availability admission control

To know more email: marketing@calsoftinc.com

Contributed by: Yogesh Patil| Calsoft inc

Calsoft’s VMware Expertise

Calsoft’s customers leverage our skills in building, testing and deploying their product in the VMware ecosystem. A few are: VMware Storage Certification, VMware Orchestrator Plugin, vCenter Plug-in development, VMware APIs for Array Integration ( VAAI ) & VMware Lab Manager

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Yogesh Patil

Yogesh Patil

Senior Test Lead at Calsoft Inc.
Software QA professional with over 10 years of industry experience. Currently working with Calsoft as a Sr. QA Lead.
His experience is across various technology domains; from Systems Engineering, Distributed Computing to Storage, Virtualization and Cloud computing.
Yogesh Patil

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