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Improve Storage Performance

VirtuCache, software for VMware vSphere to improve storage performance.

If you would like to improve storage performance of VMware, without touching the storage appliance or storage network, then our host side caching software called VirtuCache is ideal for you.

VirtuCache automatically caches all VM data (reads and writes) from your SAN based storage to in-VMware host RAM or SSD. Subsequently, VirtuCache services frequently read data and all writes from / to this in-host cache media, instead of the IO requests traversing the storage network and served by the storage appliance. This improves storage throughput and latencies considerably, thus improving the performance of applications running in VMs.

VirtuCache is very easy to deploy and manage. It can be installed while production VMs are running on the host, without requiring maintenance mode. You can choose to evaluate it by registering for VirtuCache download here.

VirtuCache deployment is seamless, in the sense that applications or end users don’t realize that most of the data is now read from and always first written to the in-host cache media, instead of backend storage array. Deploying VirtuCache doesn’t require any storage, network, or host reconfiguration (other than installing VirtuCache and assigning RAM/SSD to it).

Click here for technical details around how VirtuCache caches reads and writes; syncs writes to backend storage appliance; and protects against data loss in case of host failure.

We compete with all-flash and hybrid arrays, and hyper converged appliances.

Versus other host side caching software

We are the only host side caching software in the market currently. All the others we used to compete with like VMware’s VFRC, Infinio, PernixData, PrimaryIO, JetStream(ex-Sandisk Flashsoft), and Samsung AutoCache are all end-of-lifed.

Versus SSDs in the storage array

Here are the reasons why SSDs in the host (when used for caching with VirtuCache) work better than if the SSDs are in the backend hybrid or all-flash array

  • With VirtuCache the SSD is closer to the CPU that consumes data versus SSD in an appliance is behind the storage controllers and network. And so the same SSD will perform better in the host than in the appliance.
  • Scales performance and capacity independently – With VirtuCache, performance scales linearly as a SSD is added to each host, and it scales separately from capacity.

A quick historical note about host side caching. The first host side caching software was written by Facebook and Google for their internal Linux compute nodes. Facebook calls their software FlashCache and Google calls it Bcache. We were the first ones to do this for VMware, and we are still the only ones to cache both reads and writes, and support all VMware features seamlessly.

Versus Hyper-Converged Infrastructure (HCI).

  • VirtuCache is similar to HCI in the sense that high speed storage is back in the host.
  • Unlike HCI, VirtuCache only moves the performance tier to the VMware host, the capacity tier stays in the backend array, so you still get the advantage that traditional converged infrastructure has over HCI, that you can scale and do maintenance on storage and compute independently of each other.
  • Click here for more details on how we compete with HCI like VSAN and Nutanix.

If using RAM with VirtuCache, there is no equal in performance.

This is because storage appliances and hyper-converged boxes are not designed to use large amounts of RAM anywhere in the storage IO path. And RAM is the highest performing storage media, higher performing than even NVME SSDs.

List of storage arrays we have improved the performance of, in large numbers.

Though we support any SAN based storage appliance, below is a list of the most popular appliances at our customers that we have improved the performance of. Click on the hyperlink for your appliance to see how we compare with appliance based caching / tiering or all-flash versions of the appliance.

  • Dell-EMC Unity, VNX, VMAX, Symmetrix, and Clariion.
  • HP MSA, LeftHand Networks, P2000, VSA, Nimble, 3PAR.
  • Dell Equallogic, Compellent, VRTX (hyper-converged), Dell PowerVault ME4.
  • Netapp Appliances and Ontap Select Storage Software– We support it only when its connected to ESXi using iSCSI, FC, FCoE, not when its connected using native NAS/NFS.
  • Hitachi HDS.
  • Fujitsu Eternus.
  • Western Digital (now DDN) Tegile.
  • Pure Storage.
  • CEPH – Only when its connected to ESXi using iSCSI, not when its connected using NFS or Object protocol.
  • ZFS / Nexenta – Only when its connected to ESXi using iSCSI, not when its connected using NFS.
  • Synology over iSCSI only.
  • QNAP over iSCSI only.
  • FreeNAS over iSCSI only.
  • Windows iSCSI.


VirtuCache is ideal if you want to improve the performance of your existing SAN based storage infrastructure without requiring an upgrade to your storage network or storage appliance. Of all the alternatives on the market, VirtuCache is the easiest to deploy and the most reasonably priced.

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