Just remember that every role you customize and change during a code push you will then have to synchronize. Synchronizing is painful in my experience particularly for your production environment. We find that syncronizing the www role leaves no load balancer at times, and for a period of up to two minutes both load balancers are in place causing undefined havoc. We find that app roles stick around after the new ones have started and the load balancers send traffic to both causing more havoc for a few minutes. So we've been working hard at writing scripts that run on init such that if we lose an instance and one is restarted it configures itself with the latest code, and obviates the need to synchronize each role when we do a code push.
Our standard code pushes have been reduced from two hours to 30 minutes, and are much less error prone and less stressful. Our app role takes about 15 minutes to start and now have increased risk since a failure of the complex script could render that instance unuseable, but waiting for synchronizes to finish and their destabilizing effect was an untennable situation. On Jul 8, 2009, at 11:42 PM, Frédéric Sidler <[email protected]> wrote: > > There is a 4th role you should consider for this purpose. This is not > www, app or mysql role. > > On Thursday, July 9, 2009, kenvogt <[email protected]> wrote: >> >> I need a farm with a database server, a web server, and two distinct >> application servers for backend processing. When I login to Scalr and >> go to build a new farm, select Shared Roles, then Application >> servers, >> it only allows me to check a box for a server type. I need two of the >> app64 however. This is not a scaling issue, the servers need to do >> different things. > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "scalr-discuss" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/scalr-discuss?hl=en -~----------~----~----~----~------~----~------~--~---
