What are the real advantages of Citrix? 1

[thesleepylizard]

I'm helping set up a Citrix-based system. (Though Citrix engineers are doing the tricky parts relating to Citrix.) I've never actually used it before.

However, from what I've heard, I'm not very impressed. From my basic understand, it seems to me that there are significant disadvantages to Citrix:

* Programs run slowly, beacuse it's key presses, mouse movements, and screen shots getting transmitted - instead of just the raw data

* Large data volumes (for reasons above)

* Massive server farms required! I'm told 15-20 max users by application server: and about 1 database server for every 2-3 application servers! This is just massive compared to what I've worked with: 100 database users handled by a single server, etc.

* Expensive, for server farms, but also for licensing and hiring Citrix engineers

* Difficult to access all functions on the computer (like some ports, etc)

The only actual advantage I'm aware of is that it's much easier to deploy updates of the client software, plus perhaps monitor some things.

But I can't say too much, I've never seen it in action. Have I got all this completely wrong? Am I missing something?

 

[xs4citrix]

* Programs run slowly, beacuse it's key presses, mouse movements, and screen shots getting transmitted - instead of just the raw data

Depends on the program. If you run an application that uses internal business logic that consumes a lot of cpu, then yes it will run faster locally on a pentium 4 2.6 gigaherz, then on a citrix server, sharing power over 20 people. We call that an app that is not suitable for use on a TS/Citrix server, or you accept that downside.
The gui of an app, should work at the same speed as local.

* Large data volumes (for reasons above)

I don't quite understand you. No data should be stored on a citrix server by default. All data should be stored at fileservers, profileservers and applicationservers.

* Massive server farms required! I'm told 15-20 max users by application server: and about 1 database server for every 2-3 application servers! This is just massive compared to what I've worked with: 100 database users handled by a single server, etc.

An app can bring your server to it's knees. Either by 5 people, or by 25. Sizing a server, depends on the apps you're going to run on it, and going for the experiences of suppliers who sell you the apps. Rule of thumb i use, without any info on the apps, is to scale out at a maximum of 30 concurrent users. At that config, i am talking about a dual xeon > 2.0 and at least 1.5 gig ram.
As for the database app; Citrix servers share io for all users. What normally has to go through 1 nic, now has to go through 1 nic for 30 people. 3 of those servers is about 90 users, which comes close to the 100 you mentioned could connect on the database serverside.
If the 30 people create an unacceptable load on the citrix nic, making other services break down, then you will have to load those people over more servers. (ie 20 max)

Have you asked on the details, why the consultants, or supplier sized the servers that way?

* Expensive, for server farms, but also for licensing and hiring Citrix engineers

Citrix should only be used for true farming, or for special apps that need to be deployed that way.
In small invironments, that do not have a specific purpose, it is a waste of money, and you should try a win2k3 TS solution first. Win2k3TS is for workgroup solutions, and Citrix is big boy computing.
Citrix licenses are concurrent and farmwide. In small environments far to expensive. In large setups it is excellent. By hiring citrix engineers, you will probably double or triple the costs of the project. If your boss chooses not to send you to a citrix class, and set it up yourself; so be it. The costs are probably calculated in advance.

* Difficult to access all functions on the computer (like some ports, etc)

Correct. Various usb and com1 equipment do not handle citrix very well. Also local computercards, like pci's are a nightmare. (ie don't work) This should all be taken into consideration, before deploying citrix. Not afterwards.

Welcome to the world of SBC.

http://www.printingsupport.com

Free citrixprinting support

 

[CitrixEngineer]

What are the advantages?

You say that Citrix Engineers are "doing the tricky parts relating to Citrix".

Well, specific to Citrix, there are no really tricky parts - you install it, it works. You just have to manage applications, user profiles, printers and data, system updates, Active Directory and the rest of the network ;-)

I can't imagine what "tricky parts" the Engineers are doing. Make sure they document everything they've done and leave you with a clear guide - otherwise you may be calling them out for support more often than you expected. Database clients can be tricky things - but I see no reason why you shouldn't get more users per server, unless the client really is unsuitable for this environment. I also find it odd that you should need more than one database server - but that obviously depends on the database and the overall solution. However, if it worked with all your users on fat clients, there should be no difference with thin clients, IME.

xs4citrix has the answers to your questions over disadvantages - in short, you deploy a Citrix solution where there is a need for it, and after meticulous planning and with a good understanding of its capabilities - this is a major sea-change from PC-based computing so has its own challenges. However, the cost savings of SBC are, in the medium to long term, irrefutable.

MetaFrame comes into its own in medium to large environments, where the central administration, scalability and availability to a huge number of different clients pays back dividends. If you are going to be administering this farm, you will need training and experience of SBC - not just MetaFrame. The greatest challenges lie in getting applications to co-operate on this platform, in getting various parts of your overall network structure in order, and administering user policies and profiles.

Oh - and TEST frequently.

Good Luck!

 

[thesleepylizard]

Hi guys, thanks for your comments.

>The gui of an app, should work at the same speed as local.

I'm curious as to how it acheives this. I was under the impression that if you entered "Smith" into a field, it would send each key press to the server - and the server sends back progressive screen shots.

I can't see how this could be faster than entering "Smith" into a program running locally. Wouldn't the letters "s-m-i-t-h" appear on the screen sluggishly, slightly delayed? (Or do I misunderstand what Citrix is actually doing?)


>I don't quite understand you. No data should be stored on
>a citrix server by default. All data should be stored at
>fileservers, profileservers and applicationservers.

Of course. What I mean is, the Citrix communications system is constantly sending every single keystroke, and every changed pixel back and forth over the internet (perhaps with some compression). Of course each keystroke and changed pixels isn't much, but because every single one gets sent, surely this would add up to a lot. (Again, maybe I misunderstand what Citrix is really doing?)


>Have you asked on the details, why the consultants, or
>supplier sized the servers that way?

No, however, the advise came from both the Citrix engineers I consulted with and the software developers who wrote the actual software, and have deployed systems in the past. (ie. I trust their advice



* Expensive, for server farms, but also for licensing and hiring Citrix engineers

>By hiring citrix engineers, you will probably double or
>triple the costs of the project. If your boss chooses not
>to send you to a citrix class, and set it up yourself; so
>be it. The costs are probably calculated in advance.

lol... what really sucks is this - Mr Senior Management decided to move to this software without a costing, and without even consulting IT! When we first heard about it (somewhat indirectly!!), we did a costing of our own initiative, (~$30000AU) and warned management several months ago, and gave them several reminders. Then we hit them with it recently and they freaked out. Sigh. Communications are not good in this company.

But I'm just whining. Ignore me.


>Correct. Various usb and com1 equipment do not handle
>citrix very well. Also local computercards, like pci's are
>a nightmare. (ie don't work) This should all be taken into
>consideration, before deploying citrix. Not afterwards.

Yup. Not a problem in my case, I was just exploring the general pros and cons.


CitrixEngineer:

>and after meticulous planning and with a good
>understanding of its capabilities

lol! Dear dear, as I explained above - our management system has _cer*TAI|N correlations with Dilbertism. And us IT guys have to clean up the messes. Sorry, I'm just whining again


>However, the cost savings of SBC are, in the medium to long
>term, irrefutable.

But my question is on this one. Real idiots question, but where do the cost cuttings come in? As I explained above, it seems to me that extra data gets transfered. You still require clients (though they can now be thin).

Again, I'm a newbie to Citrix - treat me like an idiot. (management sure does haha)

Thanks again for your comments guys.

Cheers,
-lizard

 

[Palagast]

"I can't see how this could be faster than entering "Smith" into a program running locally. Wouldn't the letters "s-m-i-t-h" appear on the screen sluggishly, slightly delayed? (Or do I misunderstand what Citrix is actually doing?)"

->If you're working with a slow connection (dial-up link or so), this might happen. On a local LAN though, the network usually is by far fast enough to show you your letters and mouse actions rightaway without any noticable delay.


"But my question is on this one. Real idiots question, but where do the cost cuttings come in? As I explained above, it seems to me that extra data gets transfered. You still require clients (though they can now be thin)."

-> Exactly the point, they can be thin. One of the major advantages of using Citrix (or any Terminal Services program) is that you can use thin clients so you can buy a bigger server then without it, but you can stick to cheap desktops. Especially with larger settings this can save alot of $

 

[CitrixEngineer]

Quote /"Mr Senior Management decided to move to this software without a costing, and without even consulting IT"/ Quote

That sounds very familiar somehow... (my first encounter with Citrix back in 1996-7 - I think we had the same planners ).


Quote /"I was under the impression that if you entered "Smith" into a field, it would send each key press to the server - and the server sends back progressive screen shots." /Quote

No - MetaFrame is MUCH cleverer than that - via a system of Virtual Channels and giving each user their own virtual O/S, it breaks up, compresses and queues _only the bits of data that need to move_ up or down the wire - not the whole lot. It's a bit like the most efficient movie compression algorithm you can think of - except it's interactive. The keystrokes and sampled mouse movements move up the wire to enable that interaction, but the process (csrss.exe/gdi.exe) is running on the server the whole time. The bandwidth is around 15k. Compare that with any fat client you like.

Cost savings come in several ways - I'll give a couple, the rest are in Citrix's propaganda, I mean, sales literature

1. No need to upgrade PCs - all upgrades are done on on the server (if you run all common apps on the server).

2. No need for expensive high-end PCs at all - everyone could have 386s (if you felt mean!). What I mean is, hardware does not need to be expensive. It only tends to be once the users complain a bit that they haven't got the latest...

3. You can easily "Corporatise" the users desktops - and lock them down so they don't break anything. Not popular at first - but the Managers always seem to like it!

4. Need for less IT staff - once you have become a competent Citrix Administrator, you may have need for a "PFY" to run errands and fix a few local issues while you tend to the farm, but that's it. With an operation the size you have, I shouldn't think you'd need an extra pair of hands - just an expert website, like Tek-Tips


If your scenario matches my first assignment, you'll find that the Engineers come in, do their stuff and it all works. 3 weeks later, it all falls over, and you can't get hold of the engineers, and you spend another fortune getting someone else in to sort out the bodge job. THEN you get training and work it out yourself.

I sincerely hope not

Good Luck

 

[douglagm]

Cost-savings
1. You will have a few servers with the software installed, not hundreds of PC's. So you will need less support-staff to support the software/Applications.
2. Smaller WAN/LAN Bandwith. If Citrix is configured properly you should be able to run a session on a 28.8 kb line at local speed.
3. You can start replacing the workstation with Terminals, less hardware to support, which means less support staff.