SIMS + Terminal Server

[Gatt]

planning to virtualise most of our network soon so may cluster the remaining servers to a big TS cluster

[linescanner]

@adamf

 

I would look at 3 servers, gives you some room to breath.

 

@Gatt

 

All the really big boys warn about clustering Terminal servers

[CyberNerd]

I wouldn't virtualise terminal services unless you really have to. There have been considerable gains in performance for recent releases of the various products, but it's still one of the worst possible candidates for virtualisation.

 

Don't tell Citrix, XenApp (terminal services) on XenServer (xen) is a major selling point:

Citrix Systems » XenApp » White Papers

[Ric_]

@CyberNerd: I think the link you mean is Citrix Systems » XenApp » White Papers

 

Citrix seem to think that the Xen hypervisor is the key and I think that they are only promoting the installation of a single instance when talking about XenApp. They do seem to talk mostly about underutilised servers which is unusual in education.

 

I think that in education you would only use the virtualisation to allow for speedy recovery and dynamic provisioning, rather than consolidation.

[Tiger]

Surely working with TS to acheive a remote working facility is taking us back to time warp of terminal based remote working - yes???

 

What a waste of computing resources!!!

 

What you need is to look for a web based MIS solutions which now coming along.

 

Web based MIS also solves at a stoke other big problem of upgading client PCs with each monthly update which many of us bitterly complain in various treads in this forum. :-)

Edited April 21, 2008 by Tiger
typo

[DMcCoy]

Don't tell Citrix, XenApp (terminal services) on XenServer (xen) is a major selling point:

Citrix Systems » XenApp » White Papers

 

"Historically, these benefits have been offset by prohibitive performance degradation exhibited by other vendor solutions. However, today the server virtualization solution enabled only by Citrix XenServer makes the impact of this resource trade-off much more economically feasible."

 

 

So this just means there is a more economic tradeoff, not that its a good candidate for virtualisation. Without some sensible numbers rather than all the marketing bumf then it's difficult to know how big this trade-off is.

Edited April 21, 2008 by DMcCoy

[CyberNerd]

@CyberNerd: I think the link you mean is Citrix Systems » XenApp » White Papers

 

Citrix seem to think that the Xen hypervisor is the key and I think that they are only promoting the installation of a single instance when talking about XenApp. They do seem to talk mostly about underutilised servers which is unusual in education.

 

I think that in education you would only use the virtualisation to allow for speedy recovery and dynamic provisioning, rather than consolidation.

 

yes, down the bottom of that page is a pfd about xen/TS.

I wouldn't want to balance too many TS servers on a xen server, but consolidation is not the only benefit.

Xen's paravirtualisation is definitely the key here. It's not just about underutilisation (which does happen as not all lessons are 100% load) but being able to rapidly deploy new servers to the farm, and less cost in hardware.

The hardware costs are less because it doesn't necessarily require expensive 'server class' hardware as the xen will provide redundancy, any failures move to another box.

Agree some figures would be nice though.

[dhicks]

Surely working with TS to acheive a remote working facility is taking us back to time warp of terminal based remote working - yes???

 

Absolutely. Give it a few years and someone will come up with the revolutionary idea of migrating all these remote-access solutions to client-based (or "personal") computers. Then a few years later someone will have a bright idea about consolidating...

 

What you need is to look for a web based MIS solutions which now coming along.

 

Indeed. It's only just starting to sink in to most people that a web browser is basically a fancy-pants screen display technology with a remote procedure call mechanism. All you really need in an OS are a bunch of web browser tabs and some drivers to glue all the hardware together. However, SIMS and similar software is here, all our data is contained in it, our hard-to-train users know how to use it, therefore we are stuck with it.

 

--

David Hicks

[Geoff]

The only reason I'd consider virtualising my terminal services is in the situation where I had a beefy server with 8Gb+ of ram. I can run a 64bit Host OS and then partition it up into 4Gb 32bit Guest OS's and make full use of the hardware, without breaking any client software.

[Grommit]

Sorry but why don't you just install SIMS locally ?... save you a lot of time effort and money .... Edited April 22, 2008 by Grommit

[Gatt]

 

@Gatt

 

All the really big boys warn about clustering Terminal servers

 

Hmm.. guessing its not that simple?

[Tiger]

Dhicks

Quote:

Originally Posted by Tiger

Surely working with TS to acheive a remote working facility is taking us back to time warp of terminal based remote working - yes???

 

Absolutely. Give it a few years and someone will come up with the revolutionary idea of migrating all these remote-access solutions to client-based (or "personal") computers. Then a few years later someone will have a bright idea about consolidating...

 

I'm pleased to see someone can see where I'm coming from. ANd don't forget getting rid of the labourous chore of client installs all over the school!

 

linescanner :

All the really big boys warn about clustering Terminal servers

 

It is no brainer to understand why!

[Ric_]

@Tiger: Obviously, a nice web-based front-end would make like a lot simpler but the available products only give limited functionality through web-interfaces. As the need for remote working via multiple devices increases, it does make sense to use server-based computing for these applications.

 

By using technologies such as Sun SGD and Citrix Secure Gateway you can publish any application you want to any client through a web-browser. This has the benefits of reducing the client PC's hardware requirements and making it easier for administrators (us) to secure the remote applications (one SSL port for everything!).

[CyberNerd]

Hmm.. guessing its not that simple?

 

I think virtualising TS is something that needs to be thought through. but the fact is that the 'big boys' *are* doing it.

Assuming hardware paravirtualisation gives a 10% performance drop (I guess xenserver is more like 5% or less) we are only talking 3 users less, assuming a max 30 sessions - which means you only need another one server for every 300 users. You can now pool your underutilised DC's, fileservers, email servers, printservers into the mix and prioritise their usage, plus get the added advantage of easy deployment and high availability. I reckon in 99% of schools the underutilisation on the other servers would account for any perf loss on the Xen terminal servers.

[GrumbleDook]

When you are looking at consolidation of your servers (TS or otherwise) via virtualisation, what is your model for sustainability? Do you have a funding plan for a 5 year life span for the server? Are you looking at leasing options?

Are you pigeon holing funding for this (remembering the limited carry forward that schools can have)?

 

Consolidation into big boxes can be good ... but not only does the deployment have to be planned but a full financial breakdown needs to be looked at to make sure that you don't leave the school open to big bills at the start and the end of the life of the servers involved.

[wesleyw]

Yes but the remote working via terminal services would also mean all but a few apps could be run by staff and learners from home, in a cafe anywhere and that's the point really if the DCSF really want to push personalised and remote learning we'll have to look at this? 2D and 3D design packages can run okay over terminal services just a problem with Video and Music. It would mean then that what they see on there Network capable devices (laptops, PDAs et al) in school would be the same and the idea of only managing 20 - 50 TS servers and not 500+ PCs does have a certain appeal.

 

 

Wes

[localzuk]

Sorry but why don't you just install SIMS locally ?... save you a lot of time effort and money ....

 

Maintaining that many installs of SIMS.net is not easy. Running a TS system would be a lot quicker, take less effort and cost a lot less - in terms of time.

[cookie_monster]

@ localzuk: are you running SIMS on TS? We have over 100 SIMS users in school but will soon be going live with a small TS setup soon so will be interested in this within the next year.

 

Cheers.

[localzuk]

@ localzuk: are you running SIMS on TS? We have over 100 SIMS users in school but will soon be going live with a small TS setup soon so will be interested in this within the next year.

 

Cheers.

 

Not yet. But I intend to roll it out as and when I can. So long as I can convince my manager that it would be a good thing.

[DrCheese]

I'm looking at playing with this via a 2008 remoteapp TS box this afternoon. We've only recently started to do online registration via sims and the hassle of running 150/200 installs of sims on teacher PC's fast became apparent. Impatient teachers clicking cancel whenever an upgrade is installing, errors updating when certain user perms are set etc. A move to just a few TS servers would fantastic, then we only have to worry about updating 2/3 systems instead of the 150.

[Tiger]

DrCheese We've only recently started to do online registration via sims and the hassle of running 150/200 installs of sims on teacher PC's fast became apparent. Impatient teachers clicking cancel whenever an upgrade is installing, errors updating when certain user perms are set etc. A move to just a few TS servers would fantastic, then we only have to worry about updating 2/3 systems instead of the 150.

 

To me sadly you started on wrong foot - started with a badly written application and you are trying to put it right without realising that then you are exposing yourself badly another way.

 

1. If you look around hard enough there are online registration software that do not require the hassle of 150/200 installs.

 

2. Using TS to access admin from classooms: Have you considered data security risks by allowing 150/200 PCs accessing your admin domain via TS???

 

Good luck!

[localzuk]

To me sadly you started on wrong foot - started with a badly written application and you are trying to put it right without realising that then you are exposing yourself badly another way.

 

1. If you look around hard enough there are online registration software that do not require the hassle of 150/200 installs.

 

2. Using TS to access admin from classooms: Have you considered data security risks by allowing 150/200 PCs accessing your admin domain via TS???

 

Good luck!

 

1. Yes, there are other packages but that is beside the point.

2. Why do you assume they have a split network? We have SIMS installed on our teacher PC's which are members of our single domain...

[GrumbleDook]

@Localzuk

 

Tiger has concerns over the security of flat networks. This has been debated before and the issue of access TS to work on data is a concern to him. The solutions proposed involve people coughing up for expensive software, tying you into a particular supplier that has been known to be challenged over Patents and their treatment of schools ... erm ... much like a certain other company

 

In reality he has a valid concern but in the balance between security and usability many of us will opt for usability within the framework of the funding we have, the resources we have access too and the instructions from people higher up the chain.

[Tiger]

localzuk: Why do you assume they have a split network? We have SIMS installed on our teacher PC's which are members of our single domain...

 

On the contrary, I don't -hence the risks. For TS to work, Classroom PCs (on the curriculum network) must be on a flat network with Admin servers. This is bad news!!

 

See the Computer Weekly article this week on SQL attack vulnerability from insecure PCs - page 28 & 30. Drop me a PM if you want a copy.

Edited April 28, 2008 by Tiger
typo

[linescanner]

On the contrary, I don't -hence the risks. For TS to work, Classroom PCs (on the curriculum network) must be on a flat network with Admin servers. This is bad news!!

 

Not true if you use something like SGD sat in between both networks. This way you can control who, what why and when the admin network is access from the curriculum side.