Thin client

[SinNisTeR]

I work for a construction company (350 computer users). Many of the users are localted outside the local network at the main office. We are considering rolling out thin clients as maintenance of pcs has become too great. So I come to my fellow ATOS friends to have some questions answered.

1) What thin client solution is best? Should I just get pre-built thin client machines from HP? Would building my own be cheaper? I've thought about setting up a TFTP server and setup PXE on a DHCP server and load images onto my own thin clients. Where would I get thin clients without OSes? I'm sure they'd be cheaper. Is that the right way to deploy it?

2) What about CD-ROM support? A lot of our Project Managers need to view drawings that come from architects and other people.

3) What else should I be concerned about? Anyone here with a thin client network?

 

[Solema]

I haven't used any thin clients, but I am also interested in others' experiences.

 

[halfadder]

I have worked with SunRay terminals. They're mainly driven by a Linux or Solaris server, but from what I gather, Sun has somehow shoehorned remote desktop / windows terminal server features into their latest release.

Users can login to a SunRay terminal with a username/password, a smartcard, or both. If you go with the smartcard route, you're able to yank your card from the terminal and stick it into another terminal to instantly continue your session. You can even unplug the power to your terminal, then remove the card, and still continue working on another terminal. It's very slick.

Thin clients work well on any decently-designed switched 100BaseT network. Citrix can be a pain in the rear, but some people are able to make it dance and sing.

Personally, I would continue using "fat" PCs unless you had a really huge reason to switch to thin client. Thin clients are limited by design, and that's often a benefit, but if you don't have experience deploying thin clients, and if your users are going to need to access CD-ROM and flash drives and such, you start to lose the benefits really quick.

You can build your own PCs and netboot the ones you would like to act like "thin clients". Many people have been doing this for a long time. I have even seen netbooted labs of original G3 CRT Apple iMacs. But really, one of the huge benefits of thin clients is being able to buy cheap, small, fanless thin client boxes from Wyse, NCD, Sun, HP, etc and not having to deal with the complexity of a "real" PC.

 

[Brazen]

I think the Linux Terminal Server Project has info on this, if you are wanting to do it cheap as possible and get your hands dirty. The website is something like ltsp.org

 

[cleverhandle]

Originally posted by: SinNisTeR
Many of the users are located outside the local network at the main office.

Um... so you're talking about using thin clients over a WAN? Or am I misreading something?

 

[SinNisTeR]

Originally posted by: cleverhandle

Originally posted by: SinNisTeR
Many of the users are located outside the local network at the main office.

Um... so you're talking about using thin clients over a WAN? Or am I misreading something?

Yes, thin clients over WAN. We use Citrix for almost everything remote. We want to move towards thin clients and start doing email through citrix.

 

[drag]

Originally posted by: Brazen
I think the Linux Terminal Server Project has info on this, if you are wanting to do it cheap as possible and get your hands dirty. The website is something like ltsp.org

Ya.. Linux terminal server project is very sophisticated and mature solution for Linux desktop thin clients. But it won't generally work well over WAN links by itself, doesn't look like it's what he wants.

If your costs associated with maintaining desktops is spyware, stability and crap like that then I realy recommend keeping what you have, install Linux on them and use rdesktop to setup the remote session with the Citrix server.

As far as cheapness goes that's about the best I can think of. Keep current hardware and turn them into 'medium clients' with Linux distro's rdesktop capabilities. A decent admin should be able to set it up so that all of it is completely transparent to the end user and they shouldn't have to know what is going on.

Thin client machines are speciality things are more expensive then desktops themselves as far as hardware goes. Better to use what you got.. unless it's the hardware thats causing the cost problems. Most of the time this sort of thing is done to reduce administration overhead.

Maybe if you tell what was so expensive about the desktops somebody may help you better.

edit:
Oops.
Rdesktop is only used for connecting to Windows machines, I think now.

Citrix has it's own binary-only ICA client for Linux.

 

[TG2]

Compaq T20's and Neoware machines are the thin clients Ive been using, not sure how they would work over the WAN, but since they connect to the apps/desktops via Citrix or RDP, Im guessing it would be about the same performance.

Look into the Linux terminal server project as noted, I was interested in it as well...

 

[drag]

LTSP.org is not realy suitable for over WAN links. At least not by itself.

Typically you have low end PCs or thin clients operating on a 100mbit ethernet link connected to a switch were you end up having that switch connect to your Linux server via a 1gbit ethernet link. Typically these things are diskless and will boot up using PXE or a Netboot ROM or Netboot Floppy.

how many clients you can support depends on the workload and how you set it up. The 'thin clients' are typically low end PCs or mini-itx machines were you will use scripts (to hide the complexity from the end users) to run things like Firefox, multimedia, or VoIP applications locally on the 'thin client' then the rest is managed on the central application server. Using a configuration like that it is very simple to scale a single Dual CPU workstation with 2gigs of RAM upwards to 20 users or more. Even a hundred is possible and people have done that successfully.

Without the optimization work then you can probably get a 6-10 users on a single desktop machine without much headaches. I am guessing.

This article describes a setup were the admin deployed a call center based on LTSP and Kphone software phones and tied it into their existing Asterix PBX system (open source VoIP telephony stuff)..
http://www.linuxjournal.com/article/8165

On a default setup were everything runs on the central application server then you have to watch out for things like flash animations and such which will soak up the bandwidth and cpu time. They also recommend using low resource desktops like XFCE, Fluxbox, Icewm, or FVWM95 depending on how you feel your users will be most comfortable with. (some of them make transitioning from a Windows environment to a Linux graphical one fairly painless)

On this 'Podcast' Radio show.. "The Linux Link Tech Show" episode 97 from last year they interview a couple of the developers from Linux terminal server project. This is were I get most of my information from.
http://tllts.info/dl.php?episode=97

They discuss uses, successfull deployments, and hardware requirments.

Carefull. Portions of the show are not safe for work. Also the first 10-20 minutes is just the hosts B.S.'ing around with each other. But if your curious about it I think it's a good show to listen to.

The main advantage to this sort of setup is ease of central management after it's deployed. It is basicly the same as having multiple users on a single Linux machine. Very easy to manage and keep relatively secure.

It's not uncommon for people to mix and match terminal services. For instance if you want to deploy LTSP, but users still need to access MS Office then people will combine them having the users use X terminals, but also having them connect to Windows terminal services through rdesktop or Citrix stuff through their ICA whatnot.

This allows good migration to Linux, but allows 100% compatability with legacy windows applications. Of course this isn't what the other person is looking for, eh? 🙂

It is probably possible to extend LTSP to work well over WAN links by extending it with 'NX'. Or just using regular Linux workstations with NX.

NX technology is a way to get very high compression for the X protocol. By using this it allows you to access a Linux box graphically even over very slow links. I've used NX over a single ISDN line and it's possible to access a full fledged Gnome desktop even over 28.8 dialup. It's very impressive.

Nomachine developed NX and released the source code for the libraries under the GPL.. however they kept their client and management stuff closed source. http://www.nomachine.com/features.php It not only supports X windows, but also other stuff like VNC, rdesktop, and so on and so forth

As far as LTSP go you can roll your own, or there are a veriaty of professional support services which you can get. The professional side of the ltsp.org website is disklessworkstations.com were they sell a veriaty of LTSP compatable thin client machines. Typically diskless Mini-ITX systems.