Expert Oracle Exadata - Parent Directory

CHAPTER 1 WHAT IS EXADATA?Notice that the main system call captured on the non-Exadata platform is I/O-related (pread64). Thepoint of the previous two listings is to show that there is a very different mechanism in play in the waydata stored on disks is accessed with Exadata.Storage Server SoftwareCell Services (cellsrv) is the primary software that runs on the storage cells. It is a multi-threadedprogram that services I/O requests from a database server. Those requests can be handled by returningprocessed data or by returning complete blocks depending in the request. cellsrv also implements theResource Manager defined I/O distribution rules, ensuring that I/O is distributed to the variousdatabases and consumer groups appropriately.There are two other programs that run continuously on Exadata storage cells. Management Server(MS) is a Java program that provides the interface between cellsrv and the Cell Command LineInterface (cellcli) utility. MS also provides the interface between cellsrv and the Grid Control Exadataplug-in (which is implemented as a set of cellcli commands that are run via rsh). The second utility isRestart Server (RS). RS is actually a set of processes that is responsible for monitoring the other processesand restarting them if necessary. OSWatcher is also installed on the storage cells for collecting historicaloperating system statistics using standard Unix utilities such as vmstat and netstat. Note that Oracledoes not authorize the installation of any additional software on the storage servers.One of the first things you are likely to want to do when you first encounter Exadata is to log on tothe storage cells and see what’s actually running. Unfortunately, the storage servers are generally offlimitsto everyone except the designated system administers or DBAs. Here’s a quick listing showing theoutput generated by a ps command on an active storage server:> ps -eo ruser,pid,ppid,cmdRUSER PID PPID CMDroot 12447 1 /opt/oracle/.../cellsrv/bin/cellrssrm -ms 1 -cellsrv 1root 12453 12447 /opt/oracle/.../cellsrv/bin/cellrsbmt -ms 1 -cellsrv 1root 12454 12447 /opt/oracle/.../cellsrv/bin/cellrsmmt -ms 1 -cellsrv 1root 12455 12447 /opt/oracle/.../cellsrv/bin/cellrsomt -ms 1 -cellsrv 1root 12456 12453 /opt/oracle/.../bin/cellrsbkm-rs_conf /opt/oracle/.../cellsrv/deploy/config/cellinit.ora-ms_conf /opt/oracle/cellroot 12457 12454 /usr/java/jdk1.5.0_15//bin/java -Xms256m -Xmx512m-Djava.library.path=/opt/oracle/.../cellsrv/lib-Ddisable.checkForUpdate=true -jar /opt/oracle/cell11.2root 12460 12456 /opt/oracle/.../cellsrv/bin/cellrssmt-rs_conf /opt/oracle/.../cellsrv/deploy/config/cellinit.ora-ms_conf /opt/oracle/cellroot 12461 12455 /opt/oracle/.../cellsrv/bin/cellsrv 100 5000 9 5042root 12772 22479 /usr/bin/mpstat 5 720root 12773 22479 bzip2 --stdoutroot 17553 1 /bin/ksh ./OSWatcher.sh 15 168 bzip2root 20135 22478 /usr/bin/top -b -c -d 5 -n 720root 20136 22478 bzip2 --stdoutroot 22445 17553 /bin/ksh ./OSWatcherFM.sh 168root 22463 17553 /bin/ksh ./oswsub.sh HighFreq ./Exadata_vmstat.shroot 22464 17553 /bin/ksh ./oswsub.sh HighFreq ./Exadata_mpstat.shroot 22465 17553 /bin/ksh ./oswsub.sh HighFreq ./Exadata_netstat.shroot 22466 17553 /bin/ksh ./oswsub.sh HighFreq ./Exadata_iostat.sh16