Killing the Business Desktop PC Softly
by Johan De Gelas on July 19, 2007 3:00 AM EST- Posted in
- IT Computing
Between VDI and SBC
Meet the rock - VDI - and the hard place: SBC. Server Based Computing (SBC) might not be the most exciting technology, but it is exciting from a cost point of view. It requires one large server, which means that you have to maintain only one server OS, which can support - depending on the amount of RAM you put in that machine - up to 100 users or more. As sessions don't require that much memory and you have only one kernel running, the memory demands are generally low too. The bandwidth demands are ridiculously low: one user can work over an ISDN line. Best of all, it is much cheaper to let 100 users access one server than paying for 100 OS licenses. Of course, SBC can only be used for "CPU light" software, and for software that is compatible with Terminal Services or Citrix.
VDI doesn't have these limitations. Basically you run a lot of desktops in separate virtual machines on one or more servers. Compatibility is not a problem, as each application gets its own OS running on its own virtual machine. In a sense VDI offers the same thing as CCI, but on virtual instead of physical machines. Our own research shows that if you attach one virtual machine to one CPU core, the performance loss of virtual machine manager is negligible, between 1% (CPU intensive applications) and 8% (memory intensive applications). Once you use more virtual machines than CPUs, this quickly rises to 15% and more in some cases. This is still acceptable, but if you absolutely want the same performance as CCI, you need one core per desktop.
The disadvantage is that VMWare ESX licenses are not cheap, unless you run a lot of virtual machines per socket. It is clear that quad core CPUs are the way to go here: it makes the Intel Xeon 53xx ("Clovertown") very attractive. VDI is certainly not a replacement for Terminal Services (TS). With TS you have to manage one OS for maybe 100 users; with VDI you have to manage 100 OSes for 100 users. For those of you that are relatively new to SBC, VDI, and blade PCs, you can get a brief overview in the table below.
So where does CCI fit? This is how HP positions Blade PCs relative to SBC and VDI. The X-axis represenst the increasing complexity of the user's required software, the Y-axis the level of performance one needs.
HP sees a lot overlap between blade PCs and SBC. We don't see so much space. With quad core CPUs, 64-bit Windows 2003 (and Linux), and decent Gigabit NICs, performance shouldn't be a problem for SBC. We mention the 64-bit OS as it is important because it allows servers to take advantage of large swap spaces and more than 4GB of physical RAM. It is hard to see any reason to go blade PC when your application is compatible with Terminal Services.
Meet the rock - VDI - and the hard place: SBC. Server Based Computing (SBC) might not be the most exciting technology, but it is exciting from a cost point of view. It requires one large server, which means that you have to maintain only one server OS, which can support - depending on the amount of RAM you put in that machine - up to 100 users or more. As sessions don't require that much memory and you have only one kernel running, the memory demands are generally low too. The bandwidth demands are ridiculously low: one user can work over an ISDN line. Best of all, it is much cheaper to let 100 users access one server than paying for 100 OS licenses. Of course, SBC can only be used for "CPU light" software, and for software that is compatible with Terminal Services or Citrix.
VDI doesn't have these limitations. Basically you run a lot of desktops in separate virtual machines on one or more servers. Compatibility is not a problem, as each application gets its own OS running on its own virtual machine. In a sense VDI offers the same thing as CCI, but on virtual instead of physical machines. Our own research shows that if you attach one virtual machine to one CPU core, the performance loss of virtual machine manager is negligible, between 1% (CPU intensive applications) and 8% (memory intensive applications). Once you use more virtual machines than CPUs, this quickly rises to 15% and more in some cases. This is still acceptable, but if you absolutely want the same performance as CCI, you need one core per desktop.
The disadvantage is that VMWare ESX licenses are not cheap, unless you run a lot of virtual machines per socket. It is clear that quad core CPUs are the way to go here: it makes the Intel Xeon 53xx ("Clovertown") very attractive. VDI is certainly not a replacement for Terminal Services (TS). With TS you have to manage one OS for maybe 100 users; with VDI you have to manage 100 OSes for 100 users. For those of you that are relatively new to SBC, VDI, and blade PCs, you can get a brief overview in the table below.
| SBC Overview | |||||
| Feature | Server based computing | VDI | Blade PC | Workstation blade | Traditional fat Client |
| Client | Terminal PC | thin PC | Thin PC | Thin PC | desktop PC |
| Task of the Terminal server | Server processes application data for many clients | One virtual PC processes data for one thin client | One blade PC processes data for one thin client | One blade PC does it all, sends compressed and encrypted graphics stream to one thin client | No terminal server |
| Task of the client | Displaying GUI | Displaying GUI | Displaying GUI | Displaying the graphics stream from the workstation blade | Displaying GUI & processing business logic |
| Relation Client - terminal server | n to 1 | 1 to 1 | 1 to 1 | 1 to 1 | N/A |
| 3D graphics? | No | No | No | Yes | Yes |
| Typical tasks | Light office work | Software that is not too intensive and that doesn't work with SBC | Data mining, application development | CAD | Light office work to Heavy CAD |
| Impossible tasks | CPU or graphics intensive apps | Graphics intensive apps | Graphics intensive apps | High-end CAD applications | Nothing |
| Protocol | ICA (Citrix), RDP (MS) | RDP | RDP | RGS (HP), IBM prop. Protocol | N/A |
| Bandwidth | 0.02 to 0.03 Mbit/s | 0.03 Mbit/s | 0.03 Mbit/s | 2-4 Mbit/s | N/A |
So where does CCI fit? This is how HP positions Blade PCs relative to SBC and VDI. The X-axis represenst the increasing complexity of the user's required software, the Y-axis the level of performance one needs.
HP sees a lot overlap between blade PCs and SBC. We don't see so much space. With quad core CPUs, 64-bit Windows 2003 (and Linux), and decent Gigabit NICs, performance shouldn't be a problem for SBC. We mention the 64-bit OS as it is important because it allows servers to take advantage of large swap spaces and more than 4GB of physical RAM. It is hard to see any reason to go blade PC when your application is compatible with Terminal Services.
Facebook
Twitter
RSS
39 Comments
View All Comments
Pale Rider - Thursday, July 19, 2007 - link
I work for a fortune 500 company as a sys admin. We have 10,000 nodes (PCs and servers).Half of those are desktop business PCs and we use PCs on purpose - they fullfill the business need the best.
The facst are, most applictions do not run correctly in a terminal server or think client enviroment. Until the software developers change this and the cost of this clients come down consideranly we have no plans to move to think clients - this is true for the majority of IT departments as well.
rowcroft - Thursday, July 19, 2007 - link
It's been out there for years, but I have deployed Sun's SunRay systems and they worked great. Granted, the environment had limited Windows requirements (ran Mozilla for web and e-mail, used custom apps for business use) but those were satisfied with a Citrix deployment.If you're looking for a stable, cost effective environment (both from a productivity and hard cost savings PoV) then you should consider something like that as well.
yacoub - Thursday, July 19, 2007 - link
I'd feel horrible for anyone working in that type of locked-down environment... no freedom, no ability to use software beyond what is installed by the default image (obviously I'm talking about winamp, AIM, and other useful items, not trojans or malware), all of your programs and processing power are at the mercy of whoever dictates how much your share of the server's horsepower you're allowed to consume and what software you have access to. Ugh. What a death sentence of a work environment.And for the IT department, what a dream come true! ;)
rowcroft - Thursday, July 19, 2007 - link
Problem is, who gets to determine what's OK and what isn't? Try managing that in an enterprise environment. This isn't meant for a shop with 200 computers and one admin.yacoub - Thursday, July 19, 2007 - link
Why the preview lure text for articles that is posted on the homepage below the article title always cuts off and yet the exact sentence never seems to be found in the actual article:nobody less than who? Please finish the sentence of the preview text on the homepage, instead of burying parts of it amongst several sentences later in the article.
strikeback03 - Thursday, July 19, 2007 - link
If you go to the "IT Computing" tab at the top of the page (or whatever section the article is in) you get the whole intro blurb. they just display a portion on the homepage.punko - Thursday, July 19, 2007 - link
As a heavy guy, I resent the term "fat client".The biggest improvement in cost of ownership lately has been the change to LCD monitors. The effect is real in power savings.
The biggest headache is the licensing model change by Microsoft, AutoDesk and Adobe. This may lead to a massive shift in software to open source alternatives.
In our firm, most have PC's with a large number of laptops. Thin clients can't replace laptops, and most of us with PC's tend to push them hard, so there isn't any advantage over PC's.
Chunga29 - Thursday, July 19, 2007 - link
Give me a break - take the PC (political correctness) somewhere else, please! If you're so offended, get off your duff and get some exercise, drop the fast food, don't drink sodas or juice or alcohol, and you'll be amazed at what that can do for your obesity.And yes, you probably are clinically obese, as are 65% (and rising) Americans. I was one of them until a year ago, when I kicked my ass into shape doing the above. Dropped from 240 pounds and 31% body fat down to 190 pounds and 16% body fat, where I have been happily resting for the past six months.
Or, you can be like so many others and blame the problem on genetics, your job, etc. because weight issues certainly can't be caused by personal behavior!
NT78stonewobble - Saturday, September 15, 2007 - link
I read it as a joke.Still I WOULD blame my doctor on gaining around 30 % body weight in one year when I was twelve by giving me hormones.
Hormones that in the end wouldn't have had any effect on me. Hormones would help eg. 60 % of cases and in the rest surgery was necessary. However the initial exam of everyone with this particular problem was cut due to costs and thus everyone was given one or even two halfyear treatsments of hormones instead.
So unless you really know the guy dont ditch him.
P.S. Yes I've lost the weight since then. I am however still suffering from depressions going on the 10 th year and have an allmost anorectic relationship to food.
JohanAnandtech - Thursday, July 19, 2007 - link
Thin portables do exist, and could be a reality once Wimax and/or 3G are ubiquitous.But I do agree that the licensing models of the bige Software guys add a lot to TCO. Is it just me or is IDC always trying minimize those by grossly overestimating administration costs? :-)