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.


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/<cluster_name> OCR backups (default location)
$ORA_HOME/log/<hostname>/client/ocrconfig_<pid>.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$configured_interconnects same as above but also contains interconnects that AC is aware off that are not being used
v$service services running on an instance
x$kjmsdp display LMS daemon statistics
x$kjmddp display LMD daemon statistics

Useful 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)


Oracle RAC Daemons and Processes
OPROCd Process Monitor provides basic cluster integrity services
EVMd Event Management spawns a child process event logger and generates callouts
OCSSd Cluster Synchronization Services basic node membership, group services, basic locking
CRSd Cluster Ready Services resource monitoring, failover and node recovery
Lock Manager Server process - GCS

this is the cache fusion part, it handles the consistent copies of blocks that are tranferred between instances. It receives requests from LMD to perform lock requests. I rools back any uncommitted transactions. There can be upto ten LMS processes running and can be started dynamically if demand requires it.

they manage lock manager service requests for GCS resources and send them to a service queue to be handled by the LMSn process. It also handles global deadlock detection and monitors for lock conversion timeouts.

Lock Monitor Process - GES

this process manages the GES, it maintains consistency of GCS memory in case of process death. It is also responsible for cluster reconfiguration and locks reconfiguration (node joining or leaving), it checks for instance deaths and listens for local messaging.

A detailed log file is created that tracks any reconfigurations that have happened.

Lock Manager Daemon - GES this manages the enqueue manager service requests for the GCS. It also handles deadlock detention and remote resource requests from other instances.
Lock Process - GES manages instance resource requests and cross-instance call operations for shared resources. It builds a list of invalid lock elements and validates lock elements during recovery.
Diagnostic Daemon This is a lightweight process, it uses the DIAG framework to monitor the healt of the cluster. It captures information for later diagnosis in the event of failures. It will perform any neccessary recovery if an operational hang is detected.

General Administration

Managing the Cluster
starting /etc/init.d/init.crs start

crsctl start crs
stopping /etc/init.d/init.crs stop

crsctl stop crs
enable/disable at boot time /etc/init.d/init.crs enable
/etc/init.d/init.crs disable

crsctl enable crs
crsctl disable crs
Managing the database configuration with SRVCTL
start all instances

srvctl start database -d <database> -o <option>

Note: starts listeners if not already running, you can use the -o option to specify startup/shutdown options


stop all instances srvctl stop database -d <database> -o <option>

Note: the listeners are not stopped, you can use the -o option to specify startup/shutdown options

start/stop particular instance srvctl [start|stop] database -d <database> -i <instance>,<instance>
display the registered databases srvctl config database

srvctl status database -d <database>
srvctl status instance -d <database> -i <instance>,<instance>
srvctl status service -d <database>
srvctl status nodeapps -n <node>
srvctl status asm -n <node>

stopping/starting srvctl stop database -d <database>
srvctl stop instance -d <database> -i <instance>,<instance>
srvctl stop service -d <database> -s <service>,<service> -i <instance>,<instance>
srvctl stop nodeapps -n <node>
srvctl stop asm -n <node>

srvctl start database -d <database>
srvctl start instance -d <database> -i <instance>,<instance>
srvctl start service -d <database> -s <service>,<service> -i <instance>,<instance>
srvctl start nodeapps -n <node>
srvctl start asm -n <node>
adding/removing srvctl add database -d <database> -o <oracle_home>
srvctl add instance -d <database> -i <instance> -n <node>
srvctl add service -d <database> -s <service> -r <preferred_list>
srvctl add nodeapps -n <node> -o <oracle_home> -A <name|ip>/network
srvctl add asm -n <node> -i <asm_instance> -o <oracle_home>

srvctl remove database -d <database> -o <oracle_home>
srvctl remove instance -d <database> -i <instance> -n <node>
srvctl remove service -d <database> -s <service> -r <preferred_list>
srvctl remove nodeapps -n <node> -o <oracle_home> -A <name|ip>/network
srvctl asm remove -n <node>
OCR utilities
log file $ORA_HOME/log/<hostname>/client/ocrconfig_<pid>.log
checking ocrcheck

Note: will return the OCR version, total space allocated, space used, free space, location of each device and the result of the integrity check
dump contents ocrdump -backupfile <file>

Note: by default it dumps the contents into a file named OCRDUMP in the current directory
export/import ocrconfig -export <file>

ocrconfig -restore <file>
backup/restore # show backups
ocrconfig -showbackup

# to change the location of the backup, you can even specify a ASM disk
ocrconfig -backuploc <path|+asm>

# perform a backup, will use the location specified by the -backuploc location
ocrconfig -manualbackup

# perform a restore
ocrconfig -restore <file>

# delete a backup
orcconfig -delete <file>

Note: there are many more option so see the ocrconfig man page
add/remove/replace ## add/relocate the ocrmirror file to the specified location
ocrconfig -replace ocrmirror '/ocfs2/ocr2.dbf'

## relocate an existing OCR file
ocrconfig -replace ocr '/ocfs1/ocr_new.dbf'

## remove the OCR or OCRMirror file
ocrconfig -replace ocr
ocrconfig -replace ocrmirror

CRS Administration

CRS Administration

## Starting CRS using Oracle 10g R1
not possible

## Starting CRS using Oracle 10g R2
$ORA_CRS_HOME/bin/crsctl start crs

stopping ## Stopping CRS using Oracle 10g R1
srvctl stop database -d <database>
srvctl stop asm -n <node>
srvctl stop nodeapps -n <node>
/etc/init.d/init.crs stop

## Stopping CRS using Oracle 10g R2
$ORA_CRS_HOME/bin/crsctl stop crs
disabling/enabling ## use to stop CRS restarting after a reboot

## Oracle 10g R1
/etc/init.d/init.crs [disable|enable]

## Oracle 10g R2
$ORA_CRS_HOME/bin/crsctl [disable|enable] crs
checking $ORA_CRS_HOME/bin/crsctl check crs
$ORA_CRS_HOME/bin/crsctl check evmd
$ORA_CRS_HOME/bin/crsctl check cssd
$ORA_CRS_HOME/bin/crsctl check crsd
$ORA_CRS_HOME/bin/crsctl check install -wait 600
Resource Applications (CRS Utilities)
status $ORA_CRS_HOME/bin/crs_stat
create profile $ORA_CRS_HOME/bin/crs_profile
register/unregister application $ORA_CRS_HOME/bin/crs_register
Start/Stop an application $ORA_CRS_HOME/bin/crs_start
Resource permissions $ORA_CRS_HOME/bin/crs_getparam
Relocate a resource $ORA_CRS_HOME/bin/crs_relocate
member number/name olsnodes -n
local node name olsnodes -l
activates logging olsnodes -g
Oracle Interfaces
display oifcfg getif
delete oicfg delig -global
set oicfg setif -global <interface name>/<subnet>:public
oicfg setif -global <interface name>/<subnet>:cluster_interconnect
Global Services Daemon Control
starting gsdctl start
stopping gsdctl stop
status gsdctl status
Cluster Configuration (clscfg is used during installation)
create a new configuration clscfg -install
upgrade or downgrade and existing configuration clscfg -upgrade
clscfg -downgrade
add or delete a node from the configuration clscfg -add
clscfg -delete
create a special single-node configuration for ASM clscfg -local

brief listing of terminology used in the other nodes

clscfg -concepts
used for tracing clscfg -trace
help clscfg -h
Cluster Name Check
print cluster name cemulto -n

Note: in Oracle 9i the ulity was called "cemutls"
print the clusterware version cemulto -w

Note: in Oracle 9i the ulity was called "cemutls"
Node Scripts
Add Node addnode.sh

Note: see adding and deleting nodes
Delete Node deletenode.sh

Note: see adding and deleting nodes
displaying statistics SQL> column current_utilization heading current
SQL> column max_utilization heading max_usage
SQL> column initial_allocation heading initial
SQL> column resource_limit format a23;

SQL> select * from v$resource_limit;
Messaging (tickets)
ticket usage select local_nid local, remote_nid remote, tckt_avail avail, tckt_limit limit, snd_q_len send_queue, tckt_wait waiting from v$ges_traffic_controller;
dump ticket information

SQL> oradebug setmypid
SQL> oradebug unlimit
SQL> oradebug lkdebug -t

Lighwork Rule and Fairness Threshold
downconvert select cr_requests, light_works, data_requests, fairness_down_converts from v$cr_block_server;

Note: lower the _fairness_threshold if the ratio goes above 40%, set to 0 if the instance is a query only instance.
force dynamic remastering (DRM)

## Obtain the OBJECT_ID form the below table
SQL> select * from v$gcspfmaster_info;

## Determine who masters it
SQL> oradebug setmypid
SQL> oradebug lkdebug -a <OBJECT_ID>

## Now remaster the resource
SQL> oradebug setmypid
SQL> oradebug lkdebug -m pkey <OBJECT_ID>

Enable tracing  $ export SRVM_TRACE=true
Disable tracing  $ export SRVM_TRACE=""

Voting Disk

adding crsctl add css votedisk <file>
deleting crsctl delete css votedisk <file>
querying crsctl query css votedisk