Search the VMware Knowledge Base (KB)
View by Article ID

Virtunet Systems VirtuCache 2.x for vSphere 5.x (Partner Verified and Supported) (2116221)

  • 2 Ratings


Product Overview

This article provides information about Partner Support for deploying Virtunet Systems VirtuCache 2.x with ESXi 5.x.

Note: The Partner Verified and Supported Products (PVSP) policy implies that the solution is not directly supported by VMware. For issues with this configuration, contact Virtunet Systems directly. See the Support Workflow on how partners can engage with VMware. It is the partner's responsibility to verify that the configuration functions with future vSphere major and minor releases, as VMware does not guarantee that compatibility with future releases is maintained. 

Disclaimer: The partner product reference in this article is a software module that is developed and supported by a partner. Use of this product is also governed by the end user license agreement of the partner. You must obtain the application, support, and licensing for using this product from the partner. 


Product Overview

Virtunet Systems ( VirtuCache software improves storage performance of VMware virtual machines without requiring any upgrades to customer’s existing storage appliance or storage network. It is kernel only software that clusters in-host SSDs installed across VMware hosts together and then caches frequently and recently used data from the customer’s primary storage appliance to this clustered pool of host based SSDs. Subsequently, by writing to and serving more and more data from in-host SSDs, instead of backend storage appliance, VirtuCache substantially improves storage performance of VMware virtual machines for the customer’s existing storage appliance, thus improving the performance of applications running within virtual machines and increasing the density of virtual machines running on each host.

Deploying VirtuCache requires no downtime to your virtual machine and storage infrastructure.

  • Accelerates reads and writes. All frequently read data is cached to host based SSDs and all recent writes are written to this same SSD.
  • Since writes are written to only the local SSD without synchronously writing to the backend storage, writes on the SSD that have not been synced with backend storage (dirty writes) need to be protected against host or SSD failure. This is done by mirroring dirty writes across hosts. In case of host or SSD failure the mirrored copy of dirty writes from another host is immediately synced with the backend storage appliance.
  • Only a single software component is installed within the hypervisor. No agents in guest virtual machines and no virtual appliance per ESXi host.
  • No storage reconfiguration required.
  • Ability to control caching policy at virtual machines and Datastore level.
  • Support for vMotion, high availability, snapshots, DRS, linked clones, and storage vmotion.
  • Data center wide cache management using CLI or graphical UI within the vCenter Server.
Block Diagram

System Requirements and Deployment Details
  • Supports any operating system in the guest virtual machine.
  • Supports VMware vSphere 5.x.
  • Can Cache data to any SAS, SATA, PCIe, NVME based Flash card or Solid State Drive.
  • Can Cache data from any SATA, SAS, FC, iSCSI, and FCoE based storage.
  • VirtuCache installation does not require a virtual machine or ESXi host reboot.

Download Details

Navigate to Click Download Trials. Then register for Virtunet Systems Support credentials. Within 30 minutes, you will get a response from a Virtunet Systems Support person and the VirtuCache download binaries will be made available.

You can also contact Virtunet Systems Support at or call +1 (650) 847-8633 to request VirtuCache software and license.

Installation Details

VirtuCache has two components.

  1. VirtuCache Manager – This is a virtual machine that is downloaded as an OVA (200 MB) from Virtunet Systems Support site and imported into vCenter Server. Only one instance of VirtuCache Manager is needed per vCenter Server. Turning on the VirtuCache Manager virtual machine enables a Graphical User Interface (GUI) that allows you to manage the VirtuCache Driver software on each host in the VMware cluster from a central web based GUI or a vCenter Server plug-in. The VirtuCache Manager virtual machine is not in the storage IO path, so even if the VirtuCache Manager is off, Caching at the host level is still enabled.

  2. VirtuCache Driver – This is a Driver software packaged as a .vib file (200 KB) that is downloaded from the Virtunet Systems Support site. You can deploy this software exactly as you deploy other vib files or VMware updates. VMware’s best practices recommendation is to use Update Manager to deploy vib files. Vib files can also be installed using the VMware CLI.
For more information on installing VirtuCache Driver and Manager, See the VirtuCache Administrator’s Guide, available at the download link.

Configuration Details

With VirtuCache, datastores or virtual machines can be configured with any of the five caching policies listed in step 2.

  1. Write-Through and Write-Back Modes: The difference between Write-Through and Write-Back caching mode is in the write IO path from the virtual machine. The read IO path for both modes is the same in that recently and frequently used data is served from the SSD in both cases. In Write-Through mode, all writes are first written to the backend storage appliance based Datastore and once committed, these writes are then copied to the in-host SSD. Hence in Write-Through mode, reads are accelerated and writes are not. In Write-Back mode, all recent writes are written to the local SSD without synchronously committing the writes to backend storage appliance based Datastore. In Write-Back mode, to guard against data loss in case the local host fails, VirtuCache replicates the dirty writes to the SSD(s) in one or more ESXi hosts. The replicated dirty write cache on another host is called a Replica. In case of host failure, VirtuCache immediately syncs the Datastore with a Replica from another host. In this way the Datastore is kept consistent even in case of ESXi host failure.

  2. Caching Policies can be configured at the Datastore and virtual machine level

    There are five Caching policies:

    1. Uncached
    2. Write-Through
    3. Write-Back with 0 Replicas
    4. Write-Back with 1 Replica
    5. Write-Back with 2 Replicas. These caching policies are applied at the Datastore level and by default all the virtual machines in that Datastore inherit these policies. The Administrator can subsequently override a virtual machine’s caching policy to a different policy than what its Datastore has.
Verification Details

VirtuCache works for any VMware 5.x version.

VirtuCache was tested with this software and hardware

  • Servers and Blades on the ESXi 5.x Hardware Compatibility List (HCL)
  • FC HBAs, FCoE CNAs, and iSCSI software and hardware adapters on the ESXi 5.x HCL
Though VirtuCache was tested with software and hardware listed on the ESXi 5.x HCL, it is designed to be agnostic of SAN protocols, HBAs, iSCSI adapters, and SSDs.

Known issues and work arounds

VirtuCache is a Path Selection Plug-In (PSP) to VMware’s Native Multi-path Plug-in (NMP). If there is EMC PowerPath, EqualLogic MPP or any other non VMware MPP, these will need to be replaced with VMware’s NMP. If you choose to keep the EqualLogic MPP / EMC PowerPath / any other 3rd party MPP, Virtunet has a separate plug-in that co-exists with these storage vendor provided Multi-Path Plug-ins.

Additional Information

Support Information

Virtunet Systems Support can be reached at or at +1 (650) 847-8633

The Virtunet Systems Support website provides information and functionality related to:
  1. VirtuCache Binaries and Documentation
  2. Knowledgebase
  3. Ticketing system for prospects and customers

See Also

Request a Product Feature

To request a new product feature or to provide feedback on a VMware product, please visit the Request a Product Feature page.


  • 2 Ratings

Did this article help you?
This article resolved my issue.
This article did not resolve my issue.
This article helped but additional information was required to resolve my issue.

What can we do to improve this information? (4000 or fewer characters)

Please enter the Captcha code before clicking Submit.
  • 2 Ratings