Hi, Last year in a summer school we setup two xen installations on two different boxes running instances of the same virtual machines (ltsp servers and app servers). We spread out load with dhcp as mentioned and the homes were mounted on a third box. It worked really well.
Keeping the software versions on the servers the same is easy with xen. you update the app server on one box, and copy the whole server image over to the other box. I think you can use LVM snapshots for the same thing. You could also setup your servers without hard drives and boot them via pxe. Start Xen and then boot virtual ltsp and app servers via the network too. That means when you want more power on your app server, you just change the hardware for new ones (moore's law) No installation required. All data (xen, virtual ltsp and apps servers + homes) go on the third server that might hopefully last you quite a few years without changing. Cloning ltsp/app servers was the reason we first started getting into using xen and ltsp. Chris. On 3/7/07, Rolf-Werner Eilert <[EMAIL PROTECTED]> wrote: > Noel schrieb: > > balwant singh wrote: > >> > >> On 2/27/07, *Noel* <[EMAIL PROTECTED] > >> <mailto:[EMAIL PROTECTED]>> wrote: > >> > >> Tadeu F. Oliveira wrote: > >> > Hi, Everybody > >> > does anyone have tried LTSP with some kind of load balance? > >> > Is there any try to use LTSP with OpenMosix or something such? > >> > > >> Yes, we've tried LTSP with home-made load balancing. > >> > >> We set up two identical LTSP servers, _BOTH_ of them (that's the > >> trick) > >> with DHCP server. The only difference between them (besides IP, of > >> course) is that each DHCP server pointed to himself as TFTP > >> server, NFS > >> server and such. > >> > >> This way, the most loaded server is slower to answer the DHCP petition > >> of a booting client, thus the less loaded server answers DHCP > >> first and > >> "gets the client". > >> > >> The results we've obtained at Ejercicios Resueltos are that there > >> were > >> never more than a 20% difference in number of clients being served by > >> each LTSP twinserver. > >> > >> Greetings > >> > >> Noel Torres > >> er Envite > >> > >> > >> ------------------------------------------------------------------------- > >> > >> Take Surveys. Earn Cash. Influence the Future of IT > >> Join SourceForge.net's Techsay panel and you'll get the chance to > >> share your > >> opinions on IT & business topics through brief surveys-and earn cash > >> > >> http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > >> > >> <http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV> > >> _____________________________________________________________________ > >> Ltsp-discuss mailing list. To un-subscribe, or change prefs, goto: > >> https://lists.sourceforge.net/lists/listinfo/ltsp-discuss > >> For additional LTSP help, try #ltsp channel on irc.freenode.net > >> <http://irc.freenode.net> > >> > >> > >> > >> Interesting, we will be thankful if you may share more details about it. > >> > >> -- > >> With Best Wishes > >> balwant > >> ------------------------------------------------------------------------ > >> > >> ------------------------------------------------------------------------- > >> Take Surveys. Earn Cash. Influence the Future of IT > >> Join SourceForge.net's Techsay panel and you'll get the chance to share > >> your > >> opinions on IT & business topics through brief surveys-and earn cash > >> http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > >> ------------------------------------------------------------------------ > >> > >> _____________________________________________________________________ > >> Ltsp-discuss mailing list. To un-subscribe, or change prefs, goto: > >> https://lists.sourceforge.net/lists/listinfo/ltsp-discuss > >> For additional LTSP help, try #ltsp channel on irc.freenode.net > >> > > Well, there are no really details. > > > > Just set up two identical servers, from DHCP and up to Desktop. > > Configure them with different IP, and configure each one as if being the > > only one. > > > > Then, they will "compete" for the clients, and the most charged server > > will almost always lose the new clients in favor of the discharged one, > > as the competition is decided in the DHCPOFFER step. > > > > After having that, the remaining problem is only to cpe with the users' > > home directories, for which there are plenty of solutions, starting from > > NFS to a third dedicated server. > > > > Noel Torres > > er Envite > > > > > This is really a very good idea, but I see one more problem. From time > to time you will want to update software on the server. If you update > the software, some apps might write their data in another, new way and > users logging in to the other server after having worked with the > updated one might not be able to access their data anymore. Or even > worse, a new way of writing an .rc file might be corrupted if you start > the older version. > > How do you keep the two servers really up-to-date with EVERYTHING like > new apps and stuff? > > You see, I'm just coming from a discussion here about this. We're > planning a new LTSP server, and originally I thought it might make sense > for us to just invest into very big, very up-to-date hardware, a machine > that "does it all alone". The next thought was that we will then have > the old server to backup and mirror everything for emergency, i. e. it > might help where the new one fails. But then you will need a real > mirror-like backup of everything to be able to operate it as a good > substitution for the new server. > > This reminded me that I had read this threat here this morning and we > discussed about the way you did it. What I do not quite understand is > how you make sure that the second machine always has completely the same > software status. > > Thanks for your comments. > > Rolf > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys-and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > _____________________________________________________________________ > Ltsp-discuss mailing list. To un-subscribe, or change prefs, goto: > https://lists.sourceforge.net/lists/listinfo/ltsp-discuss > For additional LTSP help, try #ltsp channel on irc.freenode.net > ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _____________________________________________________________________ Ltsp-discuss mailing list. To un-subscribe, or change prefs, goto: https://lists.sourceforge.net/lists/listinfo/ltsp-discuss For additional LTSP help, try #ltsp channel on irc.freenode.net
