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The biggest differences are:

1. We accelerate both reads and writes, Infinio accelerates only reads.

2. Infinio doesn't support Linked Clones or Non Persistent VDI. We support all VDI features.

3. With us you can apply caching policy at the datastore and/or VM level versus only at the VM level with Infinio.

4. We accelerate IO originating in VMware kernel and VMs, versus only VM generated IO is accelerated by Infinio.

Both cache 'hot' data to in-host RAM, but the differences between Citrix MCS Storage Optimization and VirtuCache are many. The top three are:

- MCSIO works only for non-persistent Xenapp / Xendesktop VMs.¹ VirtuCache works for all VMs on the ESXi host;

- Citrix MCSIO can cache only VM writes and to VM RAM only.¹ VirtuCache can cache VM reads and writes to in-host SSD or RAM;

- With MCSIO there will be VM data loss / instability if the host fails or the RAM cache is full,¹ not so with VirtuCache.

For detailed differences, please review the table below.

For the most part both our GUI and workflows are similar. This article compares, with screenshots, steps to install and configure VirtuCache and PernixData FVP.

The only differences between us and Pernix stem from the fact that we leverage VMware's own capability in the areas of clustering, license management, and logging, whereas Pernix programmed these features separately within their software. Overall these additional screens add a few clicks and pages in Pernix versus us, but again I want to emphasize that we are more similar than different, in terms of the GUI and workflow.

In our first article, we explained the differences between our host side caching software (VirtuCache) and Datrium's (DVX DiESL). To summarize the first article, VirtuCache differs from DVX DiESL in 3 ways - (1) VirtuCache caches reads and writes to in-host cache media, Datrium caches only reads; (2) DVX DiESL only works for Datrium's own appliance, VirtuCache works for any appliance; and (3) VirtuCache can cache to in-host RAM and SSD, DVX DiESL can cache to in-host SSD only.

Now Datrium, on this link, puts forth arguments to not cache writes to in-host cache media. In this post we counter Datrium's arguments and argue for caching both reads and writes to in-host cache media.

More similar than different

Both us and PernixData differentiate from rest of the host side caching vendors in similar ways - that we are kernel mode software; both of us cache writes in addition to reads; have data protection strategies in place to prevent against data loss in case of multiple simultaneous hardware failure; do not require networking or storage to be reconfigured; and do not require agents per VM or VM per host.

This article is the first in a series of two articles that compares our software versus PernixData FVP. The second article compares (with screenshots) GUI and configuration steps for PernixData FVP and us.

Below is how we compare on important criteria.

Both Datrium and us differentiate from rest of the storage appliance vendors in that both of us cache data to cache media in the VMware host instead of in the storage appliance, which is the traditional approach. Datrium calls their host side caching component DVX DiESL, and we call our software VirtuCache.

The top three differences between Datrium and us are:

1. Our host side caching accelerates any storage appliance, Datrium’s works only for their own appliance;

2. We cache writes and reads to in-VMware host cache media, Datrium caches only reads;

3. We can cache to host RAM and SSD, Datrium can cache to in-host SSD only.

So if you are a Datrium customer and if you are looking to apply the concept of host side caching that you have come to like from Datrium, to your other storage appliances, then you could do so with VirtuCache. We will accelerate the performance of any SAN based storage appliance no matter how old or slow, by caching all storage IO (reads and writes) to any in-host SSD (or host RAM).

We believe that caching data to in-VMware host high speed media (SSD/RAM) is a better option than caching to the same media in the storage appliance because the cache media in our case is closer to the CPU that consumes ‘hot’ data, and hence the same high speed media is lower latency when installed in the VMware host than when installed in the appliance. This principle applies equally to both reads and writes and hence we cache both reads and writes to in-host SSD (or RAM). Whereas Datrium decided to cache reads in the host SSD and writes to NVRAM in their storage appliance, much like a traditional storage appliance. Datrium’s founder has these arguments to make in favor of caching writes to the appliance and NOT to in-VMware host cache media, which we patently disagree with. Our counter points to Datrium are on this link.

Also, if you use host RAM to cache with VirtuCache, VirtuCache powered infrastructure will be higher performing than any storage array or hyper-converged appliance, because no storage appliance or HCI hardware is capable of using large amounts of RAM in the storage IO path. And RAM is the highest performing storage media there is.