On Thu, Nov 07, 2002 at 11:33:27PM -0500, David Johnston wrote: > On Thu, 2002-11-07 at 08:31, rob apodaca wrote: > > On Wed, 6 Nov 2002 22:45:29 -0800 (PST) > > pedro noticioso <[EMAIL PROTECTED]> wrote: > > > > > I was thinking about the approach of separating > > > servers for different applications, meanning that if > > > the server that serves the office app dies, it will be > > > the only app not available until the server reboots, > > > without killing the complete sessions.
I don't know the circumstances for the installation, but the price of down-time might be high - even only for one application. You (or another sysadmin) might be present all the time or not. > > > What do you think about the idea? is it possible? > > > easy? hard? > > It is possible and not difficult. One way would be to mount the 'main' server's > > home dir and serve the apps via ssh. You can use ssh keys to avoid passwords. > > Then, its a matter of writing a simple shell script and using it to launch > > the app. Configuration might be more work (depending on the flexibility you give to users on issues like window-managers etc). > > I have done this and it does work well. I think its best suited if you find > > yourself working with 'stone knives and bear skins' for servers (low mem > > capacity). Computing wise it has advantages since it saves RAM. > > Otherwise, as others have pointed out, there are more elegant solutions. Saving RAM IS elegant :-) > The folks in Key Largo are doing it this way. Each major app runs on a > separate server; if a server goes down, they only lose one app. This > design works well for damage control, but it doesn't help load balancing > at all. IMHO that is a very limited form of damage control. As previously stated the price of down-time might be high - even only for one application (e.g. the window-manager). > Take a look at the Mosix packages on the K12LTSP site; you can > cluster two or more servers for load balancing. Before jumping on openMosix for load balancing understand that not all applications will tend to migrate (e.g. Mozilla, Openoffice) and that responsiveness will be effected negatively for applications that does migrate. > A guy down the street > built a small Mosix cluster for his business; I understand that he can > take a server out of the cluster without killing processes, so this > should provide better uptime, too. Better uptime than the each-application-runs-on-its-own-server solution yes, but not better uptime than Tom Lisjacs two-servers-share-the-terminals solution (which can be combined with openMosix but that does not make uptime chances better). For a server of the cluster to be removed without killing processes it must be shutdown in a clean manner. Power off will kill the processes it was running. -- Hans Ekbrand
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