Meena Vyas, Murthy Chintalapati, and Allen Gilliland, October 2008
Sun Blogs, available at http://blogs.sun.com, is a blogging service dedicated to Sun employees worldwide, hosted and managed by sun.com engineering. Blogs.sun.com is powered by Sun Java System Web Server 7.0 Update 2 (hereafter, Web Server) running on a pair of Sun Fire T2000 servers with UltraSPARC T2 processors. The site also uses a custom version of the open source blogging server Apache Roller Weblogger Version 220.127.116.11, MySQL database server, and Memcached. The service is integrated with Sun's secure single sign-on identity system backed by a worldwide employee LDAP directory for authentication and authorization.
This article presents an overview of the Sun Blogs site's usage statistics, systems architecture, and Web Server configuration. It also provides information about the system administrator's experience managing one of the busiest externally facing Web 2.0 site deployments at Sun.
This article covers the following topics:
Overall, as of September 2008, Sun Blogs hosted the following:
Table 1: Sun Blogs Statistics
The graph in Figure 1 and the table that follows show monthly raw access log statistics, analyzed by The Webalizer. For example, in August 2008, the Sun Blogs site (blogs.sun.com) served 125 million hits, averaging roughly 4 million per day.
Usage Statistics - blogs.sun.com Summary Period: Last 12 Months Generated 25-Sep-2008 04:05 PDT
Figure 1: Graph
Table 2: Summary by Month
Figure 2 shows the system architecture behind the Sun Blogs service (a mature instantiation of the Apache Roller Weblogger code). It is deployed on a pair of Sun Fire T2000 servers with 32 Gbytes of RAM, negligible local disk, and a shared file system (NFS from Sun Cluster), running Web Server 7.0 Update 2. The service is behind a hardware load balancer splitting traffic evenly. A ton of network gear on the front, from Juniper Network Netscreen firewalls to Nortel Alteon load balancers, does a lot of the heavy network work; the gear is fully redundant all the way through from the provider to the actual machines. The Sun Blogs site plans to switch soon to Sun Fire X4450 servers to take advantage of higher single-thread performance, because the Sun Fire T2000 servers are fairly under-utilized.
The database that powers all this is MySQL on Sun Fire V40z servers with 16 Gbytes of RAM and lots of internal disk. Memcached is used for optimal performance. No external storage is used. The database servers are paired (there are two of them) running in hot/standby mode.
Figure 2: System Architecture
server.xml configuration file contains information related to server runtime behavior, such as number of threads, number of concurrent connections, and Java Virtual Machine (JVM) tuning for the built-in web container to serve servlet and JSP applications. This section shows the configuration changes that the Sun Blogs team needed to make to get the desired site performance.
Here are relevant sections of the web server
server.xml configuration file, with inline comments. For the sake of brevity, only selected attributes are shown.
<server> <log> <log-file>../logs/errors</log-file> <archive-suffix>.m%d</archive-suffix> <log-level>info</log-level> </log> <http> <output-buffer-size>40960</output-buffer-size> </http> <!-- Typical worker thread pool with higher stack size not uncommon for Java web applications with deeper invocation stack depths --> <thread-pool> <max-threads>250</max-threads> <stack-size>256000</stack-size> </thread-pool> <!-- Java VM settings --> <jvm> <java-home>.../jdk</java-home> <server-class-path>...</server-class-path> <debug>false</debug> <debug-jvm-options>-Xdebug -Xrunjdwp:transport=dt_socket, server=y,suspend=n,address=7896</debug-jvm-options> <jvm-options>-Djava.security.auth.login.config=login.conf </jvm-options> <!-- Increased ms and mx; default was -Xms128m -Xmx256m --> <jvm-options>-Xms3g -Xmx3g -XX:NewSize=1g</jvm-options> <jvm-options>-server -Xsqnopause</jvm-options> <jvm-options>-XX:+UseParallelGC -XX:+UseParallelOldGC -XX:ParallelGCThreads=20</jvm-options> <!-- Added java keystore locations --> <jvm-options>-Dcom.sun.management.jmxremote -Djavax.net.ssl.keyStore=...keystore -Djavax.net.ssl.keyStorePassword=...</jvm-options> </jvm> <!-- MySQL data source configured as a JDBC resource --> <jdbc-resource> <jndi-name>jdbc/rollerdb</jndi-name> <datasource-class>com.mysql.jdbc.jdbc2.optional.MysqlDataSource </datasource-class> <property> <name>Password</name> <value>...</value> <description/> </property> <property> <name>User</name> <value>...</value> <description/> </property> <property> <name>URL</name> <value>jdbc:mysql://somedburl:12345/database?relaxAutoCommit= true&useUnicode=true&characterEncoding=utf-8</value> <description/> </property> <description>roller datasource</description> <min-connections>15</min-connections> <max-connections>250</max-connections> <idle-timeout>180</idle-timeout> <connection-validation>meta-data</connection-validation> </jdbc-resource> <mail-resource> <jndi-name>mail/Session</jndi-name> <description>roller mail session</description> <property> <name>mail.smtp.host</name> <value>mailhost</value> <description>Mail server hostname</description> </property> </mail-resource> <!-- blogs web app with document root '/' runs virtual server --> <virtual-server> <name>blogs</name> <host>blogs</host> <http-listener-name>http-listener-1</http-listener-name> <web-app> <uri>/</uri> <path>../web-app/blogs/_default</path> <description/> </web-app> </virtual-server> <!-- Logs are rotated once a day. --> <event> <time> <time-of-day>00:00</time-of-day> </time> <rotate-access-log>true</rotate-access-log> </event> <event> <time> <time-of-day>00:00</time-of-day> </time> <rotate-log>true</rotate-log> </event> </server>
Here's some information from the site administrator.
"As far as my experience with Sun Java System Web Server 7, I love it. We used Tomcat for the first couple years of the site when only Sun Java System Web Server 6.1 was available, and quite frankly, Sun Java System Web Server 6.1 lacked some features and ease of use. At that time, we preferred Tomcat, even though it lacked a lot of cool features.
Shortly after Sun Java System Web Server 7.0 came out, we switched and since then I've been a big fan. Web Server 7 offers way more features than Tomcat does, and has been very stable and nice to work with. Also, we are using Web Server because we like some of the benefits the native Web Server 7 code gives us.
One of the interesting problems we solved using Web Server 7 was an issue caused by slow clients that were tying up Web Server threads in
j2ee-module. Basically, if a client was slow and the thread got stuck in
j2ee-module, it would continue to tie up limited resources, such as database connections, and at one point, this became a real problem.
To resolve the problem, we utilized the ability of the Web Server to set a larger
output-buffer-size for each thread so that the response data for a slow client could be effectively buffered by the Web Server and the thread wouldn't be stuck in
In my experience, this ability is something you don't get from other web servers. I have found that Web Server 7 provides better integration between a native web server and a Java 2 Platform, Enterprise Edition (J2EE) container than other solutions such as Apache Tomcat.
I've also been a big fan of the Web Server
stats.xml data, which can be retrieved from the Web Server at runtime, even when the site appears to be hanging from the Web. That data has been immensely valuable in debugging Web Server issues, such as the one described previously.
Apart from that, our use of Web Server 7 has been pretty much clear sailing. We've actually been running our current installations for about a year with almost no tweaks necessary. The application just sits there and runs."
Sun Blogs (blogs.sun.com) offers a secure blogging service to thousands of Sun employees worldwide. The site runs the Apache Roller Weblogger application and is powered by Sun Java System Web Server 7.0, MySQL database, and Memcached, running respectively on pairs of Sun Fire T2000 and V40Z servers. The Sun Blogs site serves 4 million hits a day on average, representing one of the busiest Web 2.0 sun.com sites.
Meena Vyas is a software engineer with the Sun Java System Web Server development engineering team. Murthy Chintalapati was an architect and is engineering manager for Sun's Web Tier products. Allen Gilliland is a systems specialist with the sun.com engineering team that manages Sun Blogs.
Here are additional resources:
Here is a sample of output from
Sun Java System Web Server 7.0 B12/04/2006 10:15 (SunOS DOMESTIC) Server started Fri Sep 12 09:09:07 2008 Process ... started Fri Sep 12 09:09:07 2008 ConnectionQueue: ----------------------------------------- Current/Peak/Limit Queue Length 0/96/1474 Total Connections Queued 28960884 Average Queue Length (1, 5, 15 minutes) 0.00, 0.00, 0.01 Average Queueing Delay 0.05 milliseconds ListenSocket http-listener-1: ------------------------ Address http://0.0.0.0:8080 Acceptor Threads 1 Default Virtual Server blogs KeepAliveInfo: -------------------- KeepAliveCount 165/200 KeepAliveHits 13743024 KeepAliveFlushes 0 KeepAliveRefusals 1740047 KeepAliveTimeouts 2509109 KeepAliveTimeout 30 seconds SessionCreationInfo: ------------------------ Active Sessions 55 Keep-Alive Sessions 0 Total Sessions Created 250/250 CacheInfo: ------------------ enabled yes CacheEntries 275/1024 Hit Ratio 8662111/25918743 ( 33.42%) Maximum Age 30 Native pools: ---------------------------- NativePool: Idle/Peak/Limit 1/1/128 Work Queue Length/Peak/Limit 0/0/0 DNSCacheInfo: ------------------ enabled yes CacheEntries 0/1024 HitRatio 0/0 ( 0.00%) Async DNS disabled Performance Counters: ------------------------------------------------ Average Total Percent Total number of requests: 26058151 Request processing time: 0.7873 20515742.0000 default-bucket (Default bucket) Number of Requests: 26058151 (100.00%) Number of Invocations: 298097638 (100.00%) Latency: 0.0021 55890.8477 ( 0.27%) Function Processing Time: 0.7852 20459852.0000 ( 99.73%) Total Response Time: 0.7873 20515742.0000 (100.00%) Sessions: ---------------------------------------------------------------- Process Status Client Age VS Method URI Function 28793 response xxx.xx.xxx.xxx 392 blogs GET /mramcha/resource/P1010825s.JPG 28793 response xxx.xx.xxx.xxx 58 blogs GET /barton808/resource/MarksWelcome.JPG 28793 response xxx.xx.xxx.xxx 31 blogs GET /katakai/entry/php_framework_support_in_netbeans 28793 response xxx.xx.xxx.xxx 28 blogs GET /wizidm/feed/entries/atom 28793 response xxx.xxx.xx.xxx 6 blogs GET /roger/ service-j2ee 28793 request xxx.xxx.xx.xxx 4 28793 response xxx.xxx.xx.xxx 4 blogs GET /jonathan/ 28793 response xx.xxx.xxx.xxx 2 blogs GET /jimgris/feed/entries/atom 28793 response xx.xxx.xxx.xxx 1 blogs GET /PotstickerGuru/feed/entries/rss service-j2ee ....
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