load-balancing
ERROR 2013 (HY000): Lost connection to MySQL server at ‘reading authorization packet’, system error: 0
From documentation: More rarely, it can happen when the client is attempting the initial connection to the server. In this case, if your connect_timeout value is set to only a few seconds, you may be able to resolve the problem by increasing it to ten seconds, perhaps more if you have a very long distance … Read more
PHP sessions in a load balancing cluster – how?
You could set PHP to handle the sessions in the database, so all your servers share same session information as all servers use the same database for that. A good tutorial for that can be found here.
Distributed Concurrency Control
you might want to consider using Hazelcast distributed locks. Super lite and easy. java.util.concurrent.locks.Lock lock = Hazelcast.getLock (“mymonitor”); lock.lock (); try { // do your stuff }finally { lock.unlock(); } Hazelcast – Distributed Queue, Map, Set, List, Lock
Pros and Cons of Sticky Session / Session Affinity load blancing strategy?
Pros: It’s easy– no app changes required. Better utilizes local RAM caches (e.g. look up user profile once, cache it, and can re-use it on subsequent visits from same user) Cons: If the server goes down, session is lost. (Note that this is a con of storing session info locally on the web server, not … Read more
Web App: High Availability / How to prevent a single point of failure?
I have found this article on the subject: http://www.tenereillo.com/GSLBPageOfShame.htm Basically if you do not require long lasting sticky sessions you can configure your DNS servers to return multiple A records (IP addresses) for your website. Web browsers are smart enough to try all the addresses until they find one that works.
Adding machineKey to web.config on web-farm sites
This should answer: How To: Configure MachineKey in ASP.NET 2.0 – Web Farm Deployment Considerations Web Farm Deployment Considerations If you deploy your application in a Web farm, you must ensure that the configuration files on each server share the same value for validationKey and decryptionKey, which are used for hashing and decryption respectively. This … Read more