RAC Cheatsheet This is a quick and dirty cheatsheet on Oracle RAC 10g, as my experience with RAC grows I will update this section, below is a beginners guide on the commands and information that you will require to administer Oracle RAC. Acronyms Acronyms GCS Global Cache Services in memory database containing current locks and awaiting locks, also known as PCM GES Global Enqueue Services coordinates the requests of all global enqueues uses the GCS, also known as non-PCM GRD Global Resource Directory all resources available to the cluster (formed and managed by GCS and GES), see GRD for more details GRM Global Resource Manager helps to coordinate and communicate the locks requests between Oracle processes GSD Global Services Daemon runs on each node with one GSD process per node. The GSD coordinates with the cluster manager to receive requests from clients such as the DBCA, EM, and the SRVCTL utility to execute administrative job tasks such as instance startup or shutdown. The GSD is not an Oracle instance background process and is therefore not started with the Oracle instance PCM (IDLM) Parallel Cache Management formly know as (integrated) Distributed Lock Manager, its another name for GCS Resource n/a it is a identifiable entity it basically has a name or a reference, it can be a area in memory, a disk file or an abstract entity Resource (Global) n/a a resource that can be accessed by all the nodes within the cluster examples would be the following • Data Buffer Cache Block • Transaction Enqueue • Database Data Structures LVB Lock Value Block contains a small amount of data regarding the lock TRFC Traffic Controller controls the DLM traffic between instances (messaging tickets) Files and Directories Files and Directories $ORA_CRS_HOME/cdata/ OCR backups (default location) $ORA_HOME/log//client/ocrconfig_.log OCR command log file $ORA_CRS_HOME/crs/log contains trace files for the CRS resources $ORA_CRS_HOME/crs/init contains trace files for the CRS daemon during startup, a good place to start $ORA_CRS_HOME/css/log contains cluster reconfigurations, missed check-ins, connects and disconnects from the client CSS listener. Look here to obtain when reboots occur $ORA_CRS_HOME/css/init contains core dumps from the cluster synchronization service daemon (OCSd) $ORA_CRS_HOME/evm/log logfiles for the event volume manager and eventlogger daemon $ORA_CRS_HOME/evm/init pid and lock files for EVM $ORA_CRS_HOME/srvm/log logfiles for Oracle Cluster Registry (OCR) $ORA_CRS_HOME/log log fles for Oracle clusterware which contains diagnostic messages at the Oracle cluster level Useful Views/Tables GCS and Cache Fusion Diagnostics v$cache contains information about every cached block in the buffer cache v$cache_transfer contains information from the block headers in SGA that have been pinged at least once v$instance_cache_transfer contains information about the transfer of cache blocks through the interconnect v$cr_block_server contains statistics about CR block transfer across the instances v$current_block_server contains statistics about current block transfer across the instances v$gc_element contains one-to-one information for each global cache resource used by the buffer cache GES diagnostics v$lock contains information about locks held within a database and outstanding requests for locks and latches v$ges_blocking_enqueue contains information about locks that are being blocked or blocking others and locks that are known to the lock manager v$enqueue_statistics contains details about enqueue statistics in the instance v$resource_limits display enqueue statistics v$locked_object contains information about DML locks acquired by different transactions in databases with their mode held v$ges_statistics contains miscellaneous statistics for GES v$ges_enqueue contains information about all locks known to the lock manager v$ges_convert_local contains information about all local GES operations v$ges_convert_remote contains information about all remote GES operations v$ges_resource contains information about all resources known to the lock manager v$ges_misc contains information about messaging traffic information v$ges_traffic_controller contains information about the message ticket usage Dynamic Resource Remastering v$hvmaster_info contains information about current and previous master instances of GES resources in relation to hash value ID of resource v$gcshvmaster_info the same as above but globally v$gcspfmaster_info conatins information about current and previous masters about GCS resources belonging to files mapped to a particular master, including the number of times the resource has remastered Cluster Interconnect v$cluster_interconnects contains information about interconnects that are being used for cluster communication v$configured_interconnects same as above but also contains interconnects that AC is aware off that are not being used Miscellanous v$service services running on an instance x$kjmsdp display LMS daemon statistics x$kjmddp display LMD daemon statistics Useful Parameters Parameters cluster_interconnects specify a specific IP address to use for the inetrconnect _gcs_fast_config enables fast reconfiguration for gcs locks (true|false) _lm_master_weight controls which instance will hold or (re)master more resources than others _gcs_resources controls the number of resources an instance will master at a time _lm_tickets controls the number of message tickets _lm_ticket_active_sendback controls the number of message tickets (aggressive messaging) _db_block_max_cr_dba limits the number of CR copies per DBA on the buffer cache (see grd) _fairness_threshold used when too many CR requested arrive for a particular buffer and the block becomes disowned (see grd) _gc_affinity_time specifies interval minutes for reamstering _gc_affinity_limit defines the number of times a instance access the resource before remastering _gc_affinity_minimum defines the minimum number of times a instance access the resource before remastering _lm_file_affinity disables dynamic remastering for the objects belonging to those files _lm_dynamic_remastering enable or disable remastering _gc_defer_time define the time by which an instance deferred downgrading a lock (see Cache Fusion) _lgwr_async_broadcast change the SCN boardcast method (see troubleshooting)