I wanted to thank everybody who shared their Tomcat scalability stories/tips with me! Thanks a lot!
BJ Biernatowski Application Developer -----Original Message----- From: Sérgio Costa [mailto:[EMAIL PROTECTED] Sent: Tuesday, June 20, 2006 9:39 AM To: Tomcat Users List Subject: Re: Tomcat's scalability Be aware that Firewalls are known to drop idle TCP conections after a certain amount of time. We experienced a similar problem with a DB2 JDBC conection pool through a Cisco PIX. What was happening was the conections were closed by the firewall. When they were re-used, there was an added overhead until Java noticed the socket was closed, and the reconected it. We solved it through firewall configuration. Sérgio On 6/20/06, Hyatt, Gordon <[EMAIL PROTECTED]> wrote: > > We had an application (with connection pooling and validation query) > running on TC5.0.28 (now on TC5.5.17) connecting to MS SQL Server using > the Microsoft JDBC drivers. When tomcat and the database were on the same > side of the firewall performance was great (averaged < 20ms obtaining > connection and 2-3s running SELECT queries). (Yes, I actually put tracing > into the code that timed how long it took to acquire the connection, run the > query, and transmit the data back to the client.) > > Once we moved the tomcat server outside the firewall (an the SQL Server > stayed inside), the performance degraded horribly (7-10s to obtain > connection, 15-20s to run the simple queries (select by primary key), > 30s > to run the more 'complex' queries, for example SELECT id, name, description > FROM single_table WHERE name LIKE '%a%';). > > As a test, I changed the database to PostgreSQL v8.0 (at that time it was > still in beta), changed the driver, and ported the database (dropped all > indices except primary key and foreign keys), the query results were > dramatically different: < 500ms on any query I tried. I had 2 instanced of > my app on the tomcat server, one using PostgreSQL, the other using MS SQL > Server. A member of the Network Team sat with me and opened both ports > (1433 and 5432) to the database machine. > > I even reconfigured PostgreSQL to use the same port as SQL Server, > restarted tomcat, ran a set of queries using one DB then the other (shutting > the first down, obviously). The timing was still as dramatically different > as running on 2 different ports. > > I know there may have been configuration issues with the firewall that > impeded the performance, but, unfortunately, that (the firewall > configuration) was beyond my control. > > > Basically, be warned: if you are running your connection to MS SQL Server > (and using the Microsoft JDBC drivers) through a firewall, this MAY be one > contributing factor of your poor performance. > > Just my $0.02. > > Gord > > > -----Original Message----- > From: Alex Turner [mailto:[EMAIL PROTECTED] > Sent: Tuesday, June 20, 2006 12:42 AM > To: Tomcat Users List > Subject: Re: Tomcat's scalability > > > On 6/19/06, Leon Rosenberg <[EMAIL PROTECTED]> wrote: > > > > On 6/19/06, Biernatowski Bartosz J <[EMAIL PROTECTED]> > wrote: > > > I am about 90% sure the bottleneck is Tomcat or what's running on top > of > > > Tomcat. Application uses JDBC queries to MS SQL server > > > Chips are Intel Xeon. My monitoring data: > > > Memory utilization under 30%, CPU under 10%. Using hardcore > performance > > > tools and systematic approach. > > > The bottom line is that Tomcat/my application combo don't seem to > handle > > > more than a certain number of users. All I want to do is to up the # > of > > > users by 3. > > > > Sounds like your db connection pool is the problem. Maybe you should > > check whether you have enough connections in the connection pool. > > > Connection pooling, ahh yes. This is also a likely problem if you aren't > doing any. > > > > > > > So far it sounds that the approach of adding separate instance of > Tomcat > > and > > > using round robin is better than adding a separate JVM. > > I think both options are equal. How do you plan to run a separate > > tomcat in the same JVM? > > > Both options are equaly stupid. Putting multiple intances of tomcat on a > single box is pretty worthless unless you have serious application > problems. Tomcat is multi-threaded, and will by nature utilize a > multi-CPU > setup. > > > If you ask me (and hey, we have thousands of concurrent users and a > > lot more requests) you need a monitoring tool for your application > > inside your application not just vmstat or top. You need to know which > > servlet/action/whatever your presentation layer is takes the time and > > trace it down in the persistence. Everything else is just kindergarten > > :-) > > > > > > > > > > > > > BJ Biernatowski > > > Application Developer, e-Business > > > > Leon > > > > > > > > -----Original Message----- > > > From: Leon Rosenberg [mailto:[EMAIL PROTECTED] > > > Sent: Monday, June 19, 2006 10:49 AM > > > To: Tomcat Users List > > > Subject: Re: Tomcat's scalability > > > > > > are you sure that tomcat is your bottleneck? > > > Your 4 CPU machine (which cpu's btw?) should be able to handle more > > > than 1000 users (unless you are speaking about suns cpu) without > > > problems. Maybe you should provide more info about your application. > > > Do you have any monitoring data? > > > > > > Leon > > > > > > On 6/19/06, Biernatowski Bartosz J <[EMAIL PROTECTED]> > > wrote: > > > > Hello, > > > > I was hoping somebody on the list might point me in the right > > direction... > > > > > > > > I am trying to scale up Tomcat based web application currently > > supporting > > > > ~100 users to 350 users. > > > > > > > > It seems that I have enough hardware: 2 load balanced servers x 4 > CPUs > > > each > > > > with 4 GB of RAM which is underutilized for most of the time even > > though > > > > application performance slows dramatically at peak times. > > > > > > > > I was advised to install multiple JVMs in order to improve Tomcat's > > > > performance. Another option I considered was to install 2 instances > > > > of Tomcat on each server to see whether it would handle increased > > load. > > > > > > > > Would anybody know what kind of performance improvement would > multiple > > > > JVM/Tomcat installations provide? Are there any benchmarks > available? > > > > > > > > Thank you for any help! > > > > BJ > > > > > > > > BJ Biernatowski > > > > Application Developer > > > > > > > > This e-mail, including attachments, may include confidential and/or > > > proprietary information, and may be used only by the person or entity > to > > > which it is addressed. If the reader of this e-mail is not the > intended > > > recipient or his or her authorized agent, the reader is hereby > notified > > that > > > any dissemination, distribution or copying of this e-mail, including > its > > > contents and attachments, is prohibited. 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