RAC Best Practices on Linux Kirk McGowan Technical Director – RAC Pack Server Technologies Oracle Corporation Session id: 40136 Roland Knapp Principal Member Technical Staff – RAC Pack Server Technologies Oracle Corporation
Scalability by making additional processing capacity available incrementally
Private interconnect/network switch
Shared storage/concurrent access/storage switch
OS, Cluster Manager, DBMS/RAC, Application
Differences between cluster managers
RAC Hardware Architecture Clustered Database Servers Mirrored Disk Subsystem High Speed Switch or Interconnect Hub or Switch Fabric Network Centralized Management Console Storage Area Network Low Latency Interconnect ie. VIA or Proprietary Users No Single Point Of Failure Shared Cache
RAC Software Architecture Shared Disk Database Shared Data Model Shared Memory/Global Area shared SQL log buffer . . . . . . Shared Memory/Global Area shared SQL log buffer Shared Memory/Global Area shared SQL log buffer Shared Memory/Global Area shared SQL log buffer GES&GCS GES&GCS GES&GCS GES&GCS
RAC on Linux HW & SW Components public network Node1a shared storage redo log instance 1 … redo log instance 2 … control files database files Node2a cluster interconnect cache to cache N3 N4 Nn concurrent access from every node = “scale out” more nodes = higher availability Unbreakable Linux Unbreakable Linux ORACM ORACM Oracle 9 i RAC instance 1 Oracle 9 i RAC instance 2 DB cache DB cache
Installation Flowchart for Red Hat Linux AS 2.1 Boot Choose Language Select Keyboard & Mouse Choose – Advanced Server Option Use DRUID for Partition Setup Select Boot Loader Configure Network Configure Timezone Account Configuration Select Graphic Mode Boot Floppy Creation Installation Complete / Reboot
Establish file system or location for ORACLE_HOME (writable for oracle userid)
Setup host equivalence for oracle userid (.rhosts)
Installation Flowchart for OCFS Install the rpm’s on all nodes Run ocfstool as root (configures /etc/ocfs.conf) on all nodes Run load_ocfs (insmod will load ocfs.o) on all nodes Create partition on the primary node Run ocfstool to format and mount your new filesystem Mount the new filesystem on all nodes Edit rc.local or equivalent add load_ocfs and ‘mount –t ocfs <device> <mountpoint’ Download the latest OCFS rpm’s from www. ocfs .org
Remember to also download rpm’s for OCFS “Support Tools” and “Additional Tools”
Download the dd/tar/cp rpm that supports o_direct
Use rpm –Uv to install all 4 rpm’s on all nodes
Use OCFS for Oracle DB files only, not Oracle binaries (OCFS 1.0.x was not designed as a general purpose filesystem).
Installation Flowchart for oracm and Oracle Install the oracm from the 18.104.22.168 CD-ROM Configure ocmargs.ora and cmcfg.ora Load the softdog and start with ./ocmstart.sh the cluster manager on both nodes Install 22.214.171.124 software with the RAC option Kill the oracm and watchdog process modify ocmargs.ora and cmcfg.ora (remove watchdog) Load the hangcheck-timer module with lsmod Install the oracm from the 126.96.36.199 patchset Start with ./ocmstart.sh the cluster manager Install the 188.8.131.52 patchset Configure private interconnect and quorum device Fix empty directory bug
Hangcheck NM, and CM Flow (After V184.108.40.206) Oracle Instance Cluster Manager (including Node Monitor) Hangcheck-timer User-mode Kernel-mode Oracm maintains both, node status view and instance status view. The hangcheck-timer monitors the kernel for hangs, and resets the node if needed.
Bug 2820871 - ORA-29740 NODE EVICTION DESIGN ALGORITHM AND ABRUPT TIME CHANGE ARU: 220.127.116.11 ARU 4161735 completed for LINUX Intel
Bug 2420930 - GET ORA-600 [KSXPMPRP1] DURING STARTUP IN RAC MODE WITH LARGER BUFFERS. This was mysteriously included in 18.104.22.168, but not in 22.214.171.124. Bug 2875050 was opened for this issue. ARU: 126.96.36.199 ARU 4202164completed for LINUX Intel
Bug 2420930 - GET ORA-600 [KSXPMPRP1] DURING STARTUP IN RAC MODE WITH LARGER BUFFERS Bug 2922471 – Fractured block found during crash/instance recovery. Not an Oracle bug. Do not use ‘intr’ for the mount option.
Bug:2844009 - MISSING LIBCXA.SO.3 LIBRARY ISSUE IN PSR 9203. ARU: 188.8.131.52 ARU 4046387 completed for LINUX Intel
Bug 2779294 – node_list does not populated into oraInventory/ContentsXML/inventory.xml. opatch install will only apply to local node. Workaround is editing inventory.xml documented in bug 2742686.
Bug 2646914, 2675090, 2706220 and 2695783 - ORA-600 [KCCSBCK_FIRST],  on linux and W2K platform after installing 184.108.40.206. Very important patch, missing from 220.127.116.11 ARU: 18.104.22.168 ARU 4110670 completed for LINUX Intel ·
Find out the pid of the process (shell) from where oracle will be started using ps (Oracle - echo $$)
changing /proc/$pid/mapped_base to 0x10000000 and restarting oracle
Metalink Note: 200266.1
Post Installation Variable SGA Reserved for kernel DB Buffers (SGA) Default Code, etc. 0xFFFFFFFF 0xC0000000 0x50000000 0x40000000 0x00000000 Variable SGA Reserved for kernel DB Buffers (SGA) After Relink Code, etc. 0xFFFFFFFF 0xC0000000 0x15000000 0x10000000 0x00000000 mapped_base (/proc/<pid>/mapped_base) sga_base (relink Oracle) Lowering of mapped base