Brian Madden posted a topic the other day that addressed a concern by one of his readers about styles of provisioning VDI. Essentially Brian talked about thin provisioning (and the need/problem of data deduplication) versus non-persistent shared disk images and how he wishes some day we could get to a shared image/layering concept someday. The full entry is here.

Since Brian doesn't seem to think that anyone but VMware and Citrix or a small handful of  niche startups merit his attention, I felt the need to chime in on their thread to try and bring some accuracy and reality to the discussion.

The following is my response (with contributions from Leo Reiter, Virtual Bridges CTO)

There are a couple of things that bother me about the way this topic is presented.

1) The claim that "In the early days of VDI, everything was done with the persistent 1-to-1 images." is just plain wrong. If we could ever get Brian to keep one of the appointments he's asked for with Virtual Bridges he would learn that our VDI solution predates VMware's by several years and our architecture always employed stateless, gold master sessions coupled dynamically with a persistent user data image

2) The second thing is the conclusion that "this whole single-image / shared-image / layering concept, while great, is just not real today." Hello. See above. Right here. When will people start expanding the conversation beyond VMware and Citrix? Thankfully, IBM gets it. And, so does Austin Ventures who are now the backers of Virtual Bridges.

To elaborate on some technical points:

1. deduplication is a hack for needing duplication in the first place, which is an element of really bad design; despite the slickness of deduplication technology it is complicated and expensive, and is only a patch for the problem - you still need to manage separate stateful images which is no different than managing individual PC's, and therefore a non-starter for any serious VDI implementation plan.

2. delta files are also a bad approach, because they need to be thrown away when the master image is updated, and again are a patch for a bad design (see #3)

3. VERDE separates user and system data in virtual desktops of any type (Windows XP, Windows 7, Linux, etc.), therefore the "deltas" are persistent across gold master updates (this has been proven over 5 years of field deployments).  Also, the system administrator assigns a cap to the size of the user "image" for each gold master deployment ahead of time, so there is no such thing as a "runaway" delta file - you plan for the peak storage you will need (see #4), and this method is better than roaming profiles for various reasons (see #5)

4. requiring expensive SAN for VDI is both a myth and an artifact of poor early (and some current, such as View) VDI implementations. VERDE uses NAS for shared storage and connections are limited to just the servers themselves - there is no 1:1 VM->storage requirement.

5. roaming profiles vs. VERDE user persistence technology - VERDE wins here for various reasons:

     a. roaming profiles are a practice many organizations refuse to consider (this is based on talking to customers for years, not conjecture or surveys)

     b. roaming profiles typically carry a long log-in time than local profiles - sometimes much longer (measured in the 1 minute+ range in some cases)

     c. roaming profiles only work for Windows virtual desktops, which of course is fine and addresses most of the market, but encourages lock-in for the future     (like when Linux desktops become more and more useful to Enterprise in the years to come); limiting vendor lock-in at every level possible should be an important consideration for forward-looking organizations deploying VDI today

     d. roaming profiles are vulnerable to VM crashes and user aborts because you have to log off completely in order to have your data preserved - VERDE overcomes this by writing user data to persistent disk much more frequently

     e. even if roaming profiles are used, the VERDE mechanism still helps to greatly speed up logins because some per-user local persistence remains to keep the login process reasonably quick; most of the penalty of domain logons (which are typically required for roaming profile use) is creating the initial user profile bits that are assumed to be persistent - if these bits are not there, they are created each time and a huge time premium is paid; VERDE preserves these bits between logins to eliminate most of the overhead

     f. with or without roaming profile use, the VERDE mechanism provides additional per-user persistence that can be used by scripts and/or custom applications to improve the user experience or automate IT processes - this is the per-user space you get "outside roaming profiles"

In summary, VERDE marries the benefits of thin provisioning with a far superior management model that enables centralized updates without sacrificing per-user persistence, and without runaway storage requirements and costs.

Brian Madden posted an entry wondering about the future of VDI vendors who only do one thing well here. The following is my response (also posted on his site):

I think point solutions, or “one-hit wonders” are doomed.

As you point out, they are difficult to integrate into other offerings and, even if they could be integrated, the aggregate price would be astronomical.

More complete solutions, like VERDE from IBM and Virtual Bridges, offer the best hope for delivering full-featured value at an economical price… and, without the wait.

Consider that VERDE is shipping today and includes almost everything on your list of required features for successful adoption (and more): distributed connection broker, efficient hypervisor, multimedia display protocol, single Gold Master image management, personalized sessions (docs and settings), clustering, dynamic provisioning, integrated client-side hypervisor for mobile users, ability to automatically replicate gold images to branch servers/sites for overcoming any latency issues, no bit duplication at all… and all this for a paid up license of $50 per seat (in volumes of 1000 or more).

Solutions like this will begin to shine more brightly as more users emerge from their economic bunkers and begin to actually deploy VDI and see demonstrable benefits. This will separate the vendors with products that are integrated, easy to use and affordable from those that are more hype and reputation.

This is in response to Brian Madden's post today for comment on "The Madden Paradox":

 I respectfully contend that the “Madden Paradox” is fundamentally flawed because it is equating “VDI” with VMware and Citrix and not taking into account more complete offerings in the market such as VERDE from Virtual Bridges and IBM.

 IBM gave a very compelling demonstration and presentation of the newly-announced VERDE 2.0 yesterday at CloudWorld in San Francisco.

 If the world were flat then yes, the “paradox” is increasingly true. The gap between TS and VDI is increasingly negligible. But, the world is not flat, and there are vendors out there who offer truly innovative VDI, not just blatant extensions of the server consolidation paradigm with token efforts at incorporating innovations that address desktop-centric computing. Of the two, Citrix at least seems to understand the desktop better but they are the ones most caught in the teeth of the “Madden Paradox” – but that is another discussion.

 So, if you come to see the world as round, you will see that Virtual Bridges’ VERDE has been designed from the ground up as a pure VDI product and addresses most of the issues that you have been insightfully pointing out are wrong with the flat-world comparison for TS and VDI.

 When looking at The Paradox in the context of TS versus VDI, where VDI is defined as VERDE, then there are a number of distinguishing advantages of VDI over TS – and, I concede that TS still fills certain use cases better than VDI, but in meeting the needs of next generation desktop management, which is what VDI is all about, VDI has a number of distinct advantages:

 1) VDI is superior for Public Clouds and MSP’s because of the better inherent segregation of users on the same servers. This is more cost efficient (HW, SW and operating cost), more energy efficient and more flexible for serving diverse populations efficiently.

 2) VDI is superior in its ability to accommodate heterogeneous user environments - VDI allows one to seamlessly deploy a mix of XP, Windows 7 and Linux on the same infrastructure. This is important to not only future-proof your management and provisioning infrastructure, but also to make it more flexible in assigning the right desktop to the right job instead of a one-size-fits-all tariff on your desktop population.

 3) VDI is superior in Application compatibility… (as referenced above). Not only are there applications that are not TS-aware or TS-friendly, but when dealing with sensitive legacy applications with finicky food chain dependencies, it is a lot easier/cheaper to isolate and provision these from a separate gold image than it is from a separate server as is required in TS.

 4) VDI is superior in enabling disconnected use/local processing. Just because VMware and Citrix have no figured this out yet doesn't mean others haven't. VERDE has had support for disconnected use for several months. TS will never cross this barrier. VDI (VERDE) can do it today.

 5) VDI is more flexible in accommodating distributed infrastructure whereas TS requires a centralized monolithic array of servers. This is currently unique to VB, and counter-intuitive to VDI, but the ability to have regional data centers and replicated branches that are centrally managed and dynamically provisioned as opposed as having to consolidate infrastructure into data centers gives VDI a practical advantage in situations where network reliability or bandwidth is an issue.

 6) VDI servers are lower maintenance – VDI architectures are effective stateless when it comes to applications on servers whereas TS architecture needs to have applications installed on each server, and each server therefore requires more management and care. VDI involves running of desktop gold master images that are stored on disk. The applications are installed in the gold master images, not on the server.

 7) VERDE VDI has built-in storage optimization. With its minimal persistent storage requirements this compares a lot closer to TS than Vmware for example. This isn’t really an advantage of VDI over TS, but it narrows the TS advantage.

 8) In the same vein, unlike the re-purposed server-oriented hypervisors like Xen and ESX, VERDE uses a more modern hypervisor approach so that densities of our desktop-oriented hypervisor are closer to TS densities than to the densities of antiquated server-oriented hypervisor densities.

 So, in our view, VDI has several compelling and sustainable advantages over Terminal Services that will allow it to fulfill the high expectations that analysts and strategists have for it… but it will be a slow painful process if thought leaders continue to look to Vmware and Citrix for delivering on the promise.

 Unfortunately, if you concede that there is a bigger world out there beyond just Vmware and Citrix, you will have to give up on your dream of the “The Madden Paradox” being your ticket to the Industry Lexicon Hall of Fame… ;-)

Hello Fellow VDI.com members,

I am the CEO of Virtual Bridges, the makers of VERDE. We recently announded VERDE 2.0 in conjunction with IBM.

We are excited to be a part of this forum and are looking for partners and advocates for a fresh approach to VDI.

VERDE runs on Linux servers, utilizes KVM, and supports both Linux and Windows guests. VERDE is a full-featured VDI solution not just a connection broker. We include by default a massively scalable clustering model as well as support for "disconnected use" via our client-side hypervisor... so, we offer both VDI and managed desktops from the same infrastructure. We also offer true gold master dynamic provisioning. We do not store individual VMs on disk but create them dynamically upon athentication. This not only saves disk, but dramatically simplifies the management of the desktops. These attributes allow us to say with full confidence that we can deliver the fastest time to payback/ROI of any VDI vendor on the market.

Not only do we have many differentiating characteristics to VMware and Citrix, we have been at it much longer. And, we offer a very compelling price point.

If you have any questions, please drop me a note, or check us out at www.vbridges.com.

We look forward to working with you.

Jim