Session management in highly scalable web sites

Hi, Every application server has its own session management implementations for supporting high scalability. But an application architect/developer has to design and implement the application to make the best use of it. What are the guiding principles and pattern for session state management? Websphere System management red book mentions that "Session management performance is optimum when session data per user is around 2Kb. It degrades if session data is more than that". I have following questions. 1. How do you measure session data per user? 2. It is generally recommended that you should keep all the session state in database and keep only the keys in HttpSession object. Then everytime a web request is processed, session data is fetched from the database. This way all the data remains in memory only till the request is processed and actual data in HttpSession is very less. (Only few keys). What is the general practice? At what point you should be switching from keeping data in HttpSession to database? Are websites like Amazon or eBay follow this? 3. Is there any open source framework which helps you do session management in a way mentioned in point no. 2? Thanks, Unmesh Thanks, Unmesh

Click to read more ...

Sync data on all servers

I have a few apache servers ( arround 11 atm ) serving a small amount of data ( arround 44 gigs right now ). For some time I have been using rsync to keep all the content equal on all servers, but the amount of data has been growing, and rsync takes a few too much time to "compare" all data from source to destination, and create a lot of I/O. I have been taking a look at MogileFS, it seems a good and reliable option, but as the fuse module is not finished, we should have to rewrite all our apps, and its not an option atm. Any ideas? I just want a "real time, non resource-hungry" solution alternative for rsync. If I get more features on the way, then they are welcome :) Why I prefer to use a Distributed File System instead of using NAS + NFS? - I need 2 NAS, if I dont want a point of failure, and NAS hard is expensive. - Non-shared hardware, all server has their own local disks. - As files are replicated, I can save a lot of money, RAID is not a MUST. Thnx in advance for your help and sorry for my english :)

Click to read more ...

Scalable CMS?

What do you guys think/know about the scalability of the popular CMSs (like Joomla, Drupal or Typo3)? Any experience/suggestions there? I'm not sure which to pick yet... Thanks, Stephan

Click to read more ...

What software runs on this site?

It's pretty slick! olla

Click to read more ...

The Role of Memory within Web 2.0 Architectures and Deployments

Although I have a basic working knowledge of memory, SSDs and the like, I am not technical...I have never developed or deployed a system. I was exposed to ram-disks years ago, when their expense limited their use to very small files or DB applications. I am looking to "get current" on what role memory plays in curremt WEB 2.0 design and deployments. How is memory commonly used to remove latency and accelerate performance in typical Web 2.0 architectures? What role can memory play in massive scale-out implementations? Are there such a thing as memory "best practives"? If memory were cheap, would that significantly change the way systems are designed and deployed? What commercial and open source products that use memory are used, what are the benefits and trade-offs? Can anyone suggest what sources - people, books, papers, products - I might look into to gain a practical understanding of this topic?

Click to read more ...

Design Preparations for Scaling

Hi there, what do you think is crucial in the code designing of a scalable site? How does one prepare for webfarms and clusters (e.g. in PHP)? Thanks, Stephan

Click to read more ...

Technology behind mediatemple grid service

Anyone knows what's behind this service? http://www.mediatemple.net/webhosting/gs/ thanks!

Click to read more ...

Clustering Solution

Hi, I'm interested in peoples thoughts on the best choice for a database clustering solution. I have a database that is mostly varchars and numbers that doesn't store any binary data at all. It's used at about 70% read and 30% writes - though we're using memcached at the moment so it's not really hit that hard. We're currently using mysql with m/cluster, but are interested in a new solution. Possible candidate so far are unicluster (which doesn't seem mature yet.) or DRBD. Had anyone had a similar experience and can make any suggestions? Thanks

Click to read more ...

Why doesn't anyone use j2ee?

From a reader:

> Was reading through your very interesting/useful site. >Most of the architectures are non j2ee-Does that mean that >there aren't enough websites that are scalable(with youtube > like userbase) built with j2ee tech-would like to know if there > are any and their architecture as >well.

eBay uses Java, but in a very pragmatic way. They use servlets, an application server, the JDK, and they do the rest themselves. They skip JSP, entity beans, and JMS. When you need to scale putting all your eggs in one basket is a risky strategy. Why use JSP when you can do better? When use entity beans when you can do better? Use servlets because they are a very effective way of handling http requests. Use Java because it is fast, runs everywhere, and has a boat load of libraries you can use to build your build your custom system. Probably the major reason J2EE is absentee is simply LAMP. LAMP is just so incredibly functional for most 2-tier shared nothing sites they don't need a better infrastructure for writing an application tier. Personally, I pretty excited about GWT which uses Java and servlets. We'll see if that starts to take off a little bit more.

Click to read more ...

2 tier switch selection for colocation

Hi, I am interested in some experienced advice for choosing switches for a colocated 2-tier architecture. I have the hardware chosen for the webservers, app servers, and db servers, but need some advice on the network switch in between: colocation port -> firewall(load balancer) -> 2+ web servers (app servers) -> gigabit switch -> DB server(possibly cluster for future expansion) the question is that I am just starting out, i wonder which rackmount gigabit switch to select for the private LAN between the app server -> DB servers. Do I need managed for that? Cisco switches are the best, but they are the most expensive...I am looking at possibly using Dell/Netgear gigabit switches. Thanks for any input

Click to read more ...