7
Administering Multiple Instances

This chapter describes how instances are managed through initialization files and Oracle Parallel Server Manager (OPSM).

Specific topics covered in this chapter are:

• Understanding the Initialization Files
• Setting Initialization Parameters for the Oracle Parallel Server
• Managing Instances Using OPSM

Understanding the Initialization Files

An initialization parameter file is an ASCII text file containing a list of parameters. Each node consists of an initialization parameter file named INITSID.ORA with parameters unique for an instance and an initialization parameter file named INIT_COM.ORA with common parameters shared from node-to-node.

Figure 7-1 Instance Initialization Files

 

Purpose of INITSID.ORA

The INITSID.ORA initialization parameter files point to INIT_COM.ORA file for common parameters and define the:

• unique instance number
• thread number for instance
• private rollback segments for an instance

Purpose of INIT_COM.ORA

INIT_COM.ORA is called by the individual parameter files through the IFILE parameter.

Figure 7-2 Common Initialization Files

 

In a parallel server, some initialization parameters must have the same values for every instance, whether individual or common parameter files are used. By referencing the common parameter file using the IFILE parameter within the individual parameter files, instances that have individual parameter files can use the correct parameter values for those that must be identical. This also allows individual parameter files with different values.

Figure 7-3 shows the contents of INITOPS1.ORA:

Figure 7-3 INITOPS1.ORA

instance_number=1
thread=1
rollback_segments=(RB1, RB2, RB3, RB4, RB5, RB6, RB7, RB8)
ifile=c:\orant\ops\init_com.ora

Figure 7-4 shows the contents of INITOPS2.ORA:

Figure 7-4 INITOPS2.ORA

instance_number=2
thread=2
rollback_segments=(RB9, RB10, RB11, RB12, RB13, RB14, RB15, RB16)
ifile=c:\ORANT\ops\init_com.ora

Note:   During the installation process, these initialization files are automatically created.

   

Figure 7-5 shows a sample INIT_COM.ORA file:

Figure 7-5 INIT_COM.ORA

db_name=ops
db_files = 1024                                                   
control_files = `\\.\OPS_cntr01'
db_file_multiblock_read_count =  8 
db_block_buffers =  200                     
shared_pool_size =  10000000                          
log_checkpoint_interval = 10000
processes =  59                                    
parallel_max_servers = 5         
log_buffer =  8192                                   
sequence_cache_entries =  10         
sequence_cache_hash_buckets =  10   
max_dump_file_size = 10240      
background_dump_dest=%RDBMS80%\trace
user_dump_dest=%RDBMS80%\trace
db_block_size = 2048
remote_login_passwordfile = shared
text_enable = TRUE
job_queue_processes = 2
job_queue_interval = 10
job_queue_keep_connections = false
distributed_lock_timeout = 300
distributed_transactions = 5
open_links = 4
parallel_server = true

Setting Initialization Parameters for the Oracle Parallel Server

This section describes the following:

• GC_* Global Constant Parameters
• Parameter Notes for Multiple Instances
• Identical Parameters on Each Instance
• Parameter Descriptions
• Location of Initialization Files
• Editing Initialization Files

GC_* Global Constant Parameters

Initialization parameters with the prefix GC (Global Constant) are relevant only for an Oracle Parallel Server. These parameters are specified in the INIT_COM.ORA file.

Global constant parameter settings determine the size of the collection of global locks that protect the database buffers on all instances. The settings you choose affect the use of certain operating system resources.

Of the instances (OPS1, OPS2, and so on), the first instance to start up in shared mode determines the values of the global constant parameters for the other instances. The control file records the values of the GC_* parameters when the first instance starts up.

When another instance attempts to start up in shared mode, the Oracle Server compares the values of the global constant parameters in its parameter file with those already in use and issues a message if any values are incompatible. The instance cannot mount the database unless it has the correct values for its global constant parameters.

The global constant parameters for an Oracle Parallel Server are:

Parameter	Description
GC_FILES_TO_LOCKS	Gives the mapping of hashed and fine-grain locks to blocks within each data file.   The meaning of this parameter has changed. Previously, files not mentioned in this parameter (or files added later) were assigned the remaining hash locks. Files not mentioned in this parameter use DBA locking. You can now have multiple entries of GC_FILES_TO_LOCKS.
GC_LCK_PROCS	Specifies the number of LCK background processes for one instance.
GC_RELEASABLE_LOCKS	Sets the number of locks which will be used for DBA locks.
GC_ROLLBACK_LOCKS	For each rollback segment, specifies the number of instance locks available for simultaneously modified rollback segment blocks.

 

Parameter Notes for Multiple Instances

Multiple instance issues concerning initialization parameters \are summarized in the following table:

Parameter	Parallel Server Notes
CHECKPOINT_PROCESS	In Oracle Parallel Server, your database can have more datafiles. To speed up checkpoints, enable the CHECKPOINT_PROCESS parameter.
DELAYED_LOGGING_BLOCK_  CLEANOUTS	If set to TRUE, this parameter can potentially reduce pinging between instances.
DML_LOCKS	This parameter must be identical on all instances only if set to zero.
INSTANCE_NUMBER	If specified, this parameter must have unique values for different instances.
LOG_ARCHIVE_FORMAT	You must include the thread number.
MAX_COMMIT_PROPAGATION_DELAY	If you want commits to be seen immediately on remote instances, you may need to change the value of this parameter.
NLS_* parameters	This parameter can have different values for different instances.
PARALLEL_SERVER	To enable a database to be started in parallel server mode, this parameter must be set to TRUE in the initialization file.
PROCESSES	This parameter must have a value large enough to allow for all background processes and all user processes in an instance. Some operating systems can have additional DBWR processes. Defaults for the SESSIONS and TRANSACTIONS parameters are derived directly or indirectly from the value of the PROCESSES parameter. If you do not use the defaults, you may want to increase some of these parameter values to allow for optional background processes.
RECOVERY_PARALLELISM	To speed up the roll forward or cache recovery phase, you can set this parameter.
ROLLBACK_SEGMENTS	Specify the private rollback segments for each instance.
THREAD	If specified, this parameter must have unique values for different instances.

 

Identical Parameters on Each Instance

Certain initialization parameters are critical at database creation or affect certain database operations. These parameters must have the same value for every instance in an Oracle Parallel Server specified in each INIT_COM.ORA file for each instance. For example, the values of DB_BLOCK_SIZE and CONTROL_FILES must be identical for every instance. Other parameters can have different values for different instances; for example, INIT_SQL_FILES can have any value because it is ignored except when the database is created.

The following initialization parameters must have identical values for every instance in a parallel server:

CACHE_SIZE_THRESHOLD	LM_LOCKS (identical values recommended)
CONTROL_FILES	LM_PROCS (identical values recommended)
CPU_COUNT	LM_RESS (identical values recommended)
DB_BLOCK_SIZE	LOG_FILES
DB_FILES	MAX_COMMIT_PROPAGATION_DELAY
DB_NAME	PARALLEL_DEFAULT_MAX_INSTANCES
DML_LOCKS (must be identical only if set to zero)	PARALLEL_DEFAULT_MAX_SCANS
GC_FILES_TO_LOCKS	ROLLBACK_SEGMENTS
GC_LCK_PROCS	ROW_LOCKING
GC_ROLLBACK_LOCKS	SERIALIZABLE

 

Setting LM_* Parameters

Set values for the LM_* initialization parameters. Note that the resources, locks and processes configurations are per OPS instance. For ease of administration, these parameters should be consistent for all the instances.

LM_LOCKS	Number of locks. Where R is the number of resources, N is the total number of nodes, and L is the total number of locks, the following calculation is used:   L = R + (R*(N - 1))/N
LM_PROCS	Number of processes. The value of PROCESSES initialization parameter multiplied by the number of nodes.
LM_RESS	This parameter controls the number of resources that can be locked by the Lock Manager. This parameter covers the number of lock resources allocated for DML, DDL (data dictionary locks), and data dictionary cache locks + file and log management locks.

 

Parameter Descriptions

Chapter 18, "Administering Multiple Instances," of the Oracle8 Parallel Server Concepts & Administration includes descriptions of the initialization parameters:

Location of Initialization Files

The database for which the instance is started must have access to the appropriate initialization parameter files. Oracle Parallel Server uses the initialization parameter files located in ORACLE_HOME\DATABASE, unless you specify a different initialization file with the PFILE option at startup.

Editing Initialization Files

To customize Oracle Parallel Server for Windows NT databases functions, you need to edit the initialization parameter files. Use any ASCII text editor to modify the file.

Managing Instances Using OPSM

Although instances can be started and stopped individually from each node using Server Manager, it is not always the most efficient way. OPSM allows you to manager, start and stop one or more instances from one node or from an Oracle Enterprise Manager Console, thus centralizing the management of instances.

Additional Information:   See Chapter 6, "Installing and Configuring Oracle Parallel Server Manager", for OPSM requirements and setup.

   

Using OPSM from the Oracle Enterprise Manager Console

After the repository is built, the Oracle Enterprise Manager Console appears with access to the Oracle Parallel Servers in the Navigator tree. An instance or multiple instances are started or stopped by:

• right-clicking the mouse on a parallel server, and choosing either Startup or Shutdown from the Navigator tree
• executing an Oracle Parallel Server start up/shut down job from the Job menu

.

Additional Information:   See Chapter 2, "Oracle Parallel Server Management Operations", in the Oracle Parallel Server Management User's Guide and the Oracle Enterprise Manager Administrator's Guide for further information about managing Oracle Parallel Servers and parallel server instances from Oracle Enterprise Manager.

   

If you configured the Oracle Performance Manager, you can display a variety of tabular and graphic performance statistics for parallel server.

Additional Information:   See the Oracle Parallel Server Management User's Guide for further information about using the Oracle Enterprise Manager Console and Oracle Performance Manager.

   

Using OPSM from OPSCTL

The OPSCTL.EXE utility allows you to manage all Oracle Parallel Server instances from each node. You can choose to start or stop all instances on an individual node.

Understanding OPSCTL Requirements

Note:   The following requirements are met if you followed all the steps in Chapter 5, "Configuring Oracle Parallel Server" and Chapter 6, "Installing and Configuring Oracle Parallel Server Manager".

   

OPSCTL requires the following:

• The name of each service must be exactly the same as the Oracle SID for that instance (and exactly the same as they appear in the registry).
• The database initialization files must follow a format of INITSID.ORA and be located in the ORACLE_HOME\DATABASE directory.
• The database initialization files for all instances of your Oracle Parallel Server must exist on the node where OPSCTL.EXE is run.
• A new Windows NT user with the same name as the one you are using to access your Oracle Enterprise Manager console workstation must be created on all nodes of your Oracle Parallel Server.

OPSCTL.EXE uses this user to start services on remote machines, so this user must have the equivalent of administrator access on each of the nodes. You can either use the default Oracle Enterprise Manager Console credential to access your Oracle Parallel Server or supply a different account name/password combination when creating a startup/shutdown job. In either case, the account used must have DBA privileges on an instance of Oracle Parallel Server in order to start or stop that instance.

Startup

OPSCTL START Command Line Usage

OPSCTL START -CCONNECT_STRING -NDATABASE_NAME  [-ISID, SID] [-F] [-T] [-U] [-M] 

[-Y|-E] [-v] [-h]

Note:   [] indicates optional items.

   

where:

Parameter	Specifies
-CCONNECT_STRING	connect string, such as INTERNAL/MANAGER
-NDATABASE_NAME	name of the Oracle Parallel Server database name to start; defined in the INIT_COM.ORA file
-ISID, SID	to start specified instance(s) only
-F	startup of instances following an ABORT shutdown; default is IMMEDIATE
-T	RESTRICTED SESSION privileges only
-U	database not to be mounted upon startup
-M	mount, but do not open the database
-Y	retry database opening if recovery is in progress
-E	EXCLUSIVE mount and open
-V	verbose
-H	print usage

 

To start all instances:

C:\> CD ORACLE_HOME\BIN
C:\ORACLE_HOME\BIN> OPSCTL START -CINTERNAL/PASSWORD -NDATABASE_NAME

To start an individual instance:

C:\> CD ORACLE_HOME\BIN
C:\ORACLE_HOME\BIN> OPSCTL START -ISID -CINTERNAL/PASSWORD -NDATABASE_NAME

Shutdown

OPSCTL STOP Command Line Usage

OPSCTL STOP -CCONNECT_STRING -NDATABASE_NAME  [-ISID, SID] [-F] [-T] [-U] [-M] 

[-v] [-h]

Note:   [] indicates optional items.

   

where:

Parameter	Specifies
-CCONNECT_STRING	connect string, such as INTERNAL/MANAGER
-NDATABASE_NAME	name of the Oracle Parallel Server database name to stop; defined in the INIT_COM.ORA file
-ISID, SID	to stop specified instance(s) only
-F	shutdown of instances in ABORT mode; default is IMMEDIATE
-T	RESTRICTED SESSION privileges only
-U	database not to be mounted upon startup
-M	NORMAL mode of shutdown; default is IMMEDIATE
-V	verbose
-H	print usage

 

To stop all instances:

C:\> CD ORACLE_HOME\BIN
C:\ORACLE_HOME\BIN> OPSCTL STOP -CINTERNAL/PASSWORD -NDATABASE_NAME

To stop an individual instance:

C:\> CD ORACLE_HOME\BIN
C:\ORACLE_HOME\BIN> OPSCTL STOP -ISID -CINTERNAL/PASSWORD -NDATABASE_NAME

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