Thursday, October 25, 2007 at 9:42PM I just heard about some web sites where Velocity templates are used to render HTML instead of using JSPs and all the processing in performed in servlets. Can JSPs cause issue with scalability? Thanks, Unmesh
Thursday, October 25, 2007 at 12:51PM Who can answer or analyze the image store and visit solution about alibaba.com?Thanks
Monday, October 15, 2007 at 12:49PM Hello,everybody,I'm plant to building a new website like 2008.sina.com.cn 2008.sohu.com .site contents have pic news,text news,and video news.user blog ....now I have a question to ask everybody,I hope can get usefully information to here. status: 100,000,000 people /per day 50,000 people /peak time more than 200 servers OpenBSD/Opensuse Apache Fast CGI modules lighttpd for picture Mysql varnish LVS lucene search do you have a good idea to it?thans for everybody!
Sunday, October 14, 2007 at 11:35PM I have 3 exp in building website using java.I work on only single server.Website is not very scalable.I always wonder how ebay,youtube,monster handle traffic, giving responses within seconds.From the google i find this site and i hope i can also able to build very scalable website .I need guidelines from where to start ,what are the things we needed.I know that scalability comes through the use of distributed applications but don't how to implement it. I see many website build in languages other than java so java is good choice for building high scalable website. Thanks
Tuesday, October 9, 2007 at 5:51PM Hi everybody :) We have a bunch of webservers (about 14 at this time) running Apache. As application framework we're using PHP with the APC Cache installed to improve performance. For load balancing we're using a Big F5 system with dynamic ratio (SNMP driven) To sync new/updated sourcecode we're using subversion to "automaticly" update these servers with our latest software relases. After updating the new source to these production servers the load of the mashines is raising to hell. While updating the servers, they are still in "production", serving webpages to the users. Otherwise the process of updating would take ages. Most of the time we're only updating in the morning hours while less users are online, because of the above issue. My guess is, that the load is raising that high, because APC needs to recompile a bunch of new files each time. Before and while compiling the performance simply is "bad". My goal would be to find a better solution. We want to "sync" code no matter how many users are online (in case of emergency) without taking the whole site down. How you're handling this issues ? What do you think about the process above ? Do you may find the "problem" ? Do you have similiar issues ? Feedback is highly welcome :) Greetings, Stephan Tijink Head of Web Development | fotocommunity GmbH & Co. KG | Rheinwerkallee 2 | 53227 Bonn
Sunday, October 7, 2007 at 3:59PM Hi, In java web servers, each http request is handled by a thread in thread pool. So for a Servlet handling the request, a thread is assigned. It is tempting (and very convinient) to keep context information in the threadlocal variable. I recently had a requirement where we need to assign logged in user id and timestamp to request sent to web services. Because we already had the code in place, it was extremely difficult to change the method signatures to pass user id everywhere. The solution I thought is class ReferenceIdGenerator { public static setReferenceId(String login) { threadLocal.set(login + System.currentMillis()); } public static String getReferenceId() { return threadLocal.get(); } private static ThreadLocal threadLocal = new ThreadLocal(); } class MySevlet { void service(.....) { HttpSession session = request.getSession(false); String userId = session.get("userId"); ReferenceIdGenerator.setRefernceId(userId); try { doSomething(); } finally { ReferenceIdGenerator.remove(); } } This method is also discussed at http://crazybob.org/2006/07/hard-core-java-threadlocal.html Is this a reasonable approach to pass context information in web application? Can this ever happen that while a http request is being processed in the thread, a thread is suddenly assigned to some other tasks? I hope this can never happen, because app servers themselves rely heavily on threadlocals to keep transaction related information around. What do you think? Thanks, Unmesh
Thursday, October 4, 2007 at 4:20AM Hello, Does someone know or has an idea of how many load balanced servers there might be? Thanks, Antoni www.amasso.info
Wednesday, October 3, 2007 at 3:25AM Monday, October 1, 2007 at 2:26AM My company is developing a centralized web platform to service our clients. We currently use about 3Mb/s on our uplink at our ISP serving web pages for about 100 clients. We'd like to offer them statistics that mean something to their businesses and have been contemplating writing our own statistics code to handle the task. All statistics would be gathered at the page view level and we're implementing a HttpModule in ASP.Net 2.0 to handle the gather of the data. That said, I'm curious to hear comments on writing this data (~500 bytes of log data/page request). We need to write this data somewhere and then build a process to aggregate the data into a warehouse application used in our reporting system. Google Analytics is out of the question because we do not want our hosting infrastructure dependant upon a remote server. Web Trends et al. are too expensive for our clients. I'm thinking of a couple of options. 1) Writing log data directly to a SQL Server 2000 db and having a Windows Service come in periodically to summarize and aggregate the data to the reporting server. I'm not sure this will scale with higher load and that the aggregation process will timeout because of the number of inserts being sent to the table. 2) Write the log data to a structure in memory on the web server and periodically flush the data to the db. The fear here is that the web server goes down and we lose all the data in memory. Other fears are that the IIS processes and worker threads might mangle one another when contending for the memory system resource. 3) Don't use memory and write to a file instead. Save the file handler as an application variable and use it for all accesses to the file. Not sure about threading issues here as well and am reluctant to use anything which might corrupt a log file under load. 4) Add comment data to the IIS logs. This theoretically should remove the threading issues but leaves me to think that the data would not be terribly useful once its in the IIS logs. The major driver here is that we do not want to use any of the web sites and canned reports built into 90% of all statistics platforms. Our users shouldn't have to "leave" the customer care portal we're creating just to see stats for their sites. IFrames are not an option. I'm looking for a solution that's not entirely complex, nor is it overly expensive and it will give me the access to the data we need to record on page views. It has to scale with volume. Thoughts are appreciated. Derek
Sunday, September 23, 2007 at 6:31PM Hi, Can someone teach me how you implement network switch fail over since we are paranoid for single point of failure. For example, you have: a dozen web servers -> switch -> DB cluster that switch is a SPOF. How does one implement dual switch in a fail over fashion?
