(Les05 ASM Instance) [1, 20180208], les0520180208

(Les05 ASM Instance) [1, 20180208], les0520180208
Learning objectives description use the benefits of ASM to manage the creation and deletion of ASM instances extended ASM disk groups use various utilities to retrieve the benefits of ASM metadata for administrators Using ASM can be exempted from: -I/O performance optimization: ASM adopts the strategy of striping and mirroring all data and performs automatic rebalancing. -Move and reorganize data files: you no longer need to change the location of data files to meet performance requirements and space constraints. -File name management: you no longer need to define and enforce file naming policies-logical volume/File System/Cluster File System/bare device management: you no longer need these storage elements to use ASM to reduce the following tasks: -Management of logical unit numbers (Luns) is reduced. Generally, ASM requires fewer and larger logical units.-The dependency between database operators and system administrators is greatly reduced, if the migration of a disk group does not require system administrator intervention. -Reduce errors that occur when manual maintenance tasks are executed. The naming of new data file files is not standardized, and the rest of the database is not supported. Each time the ASM instance starts the ASM or database, it will allocate a shared memory area named system global zone (SGA) and start the Oracle ASM and database background processes ,. The background process and the SGA group are called Oracle ASM instances or Oracle DB instances. The SGA in the ASM instance is divided into four main areas:-shared pool: for metadata-large pool: for parallel-ASM cache: for reading and writing Blocks During the rebalancing operation-idle memory: the recommended minimum memory for available unallocated memory ASM is 256 MB. By default, automatic memory management is enabled for ASM instances. This function dynamically optimizes the size of each SGA memory component. The amount of memory required by the ASM instance depends on the amount of disk space managed by the ASM. The second part of the ASM instance is the background process. The ASM instance can have multiple background processes, not all processes always appear. ASM component-ARCn: archiving process-SMON: system monitoring process-PMON: Program monitoring process-DBWn: Database writing process-LGWR: log writing process-CKPT: Checkpoint Process-DIGA: diagnostic process-Jnnn: Job Queue process-QMNn: queue monitoring process-PSP0: Process derivative process-RECO: recoverer process-VKTM: Virtual timer process-MMAN: process of the Memory Manager Process ASM in the RAC cluster-LMON: global service monitoring process-LMDn: global service daemon-LMSn: Global cache service process-LCKn: lock process ASM instance-main process-RBAL: Coordinating rebalancing activities-ARBn: one or more subordinate processes for performing rebalancing activities-GMON: Managing disk-level activities, such as deleting or going offline and improving the compatibility of ASM disk groups-MARK: MARK the ASM allocation unit as obsolete-Onnn: one or more ASM subordinate processes as needed, creates a set of connections with the ASM instance for message exchange. -PZ9n: one or more parallel subordinate processes used to extract the data ASM instance initialization parameter-INSTANCE_TYPE: Set ASM, this is the only parameter that must be defined. For database instances, this parameter is set to RDBMS-ASM_POWER_LIMIT to control the speed of the rebalance operation. The value range is from 1 to 11 (the default value is 1 ). -ASM_DISKSTRING: it is an operating system-related value. ASM uses it to restrict the disk set to be considered during search (empty by default, indicating all ). -ASM_DISKGROUPS: List of names of the disk groups to be loaded by the ASM instance. This parameter has no default value. -ASM_PREFERRED_READ_FAILURE_GROUPS: Specifies the fault group that contains the preferred disk read. -DIAGNOSTIC_DEST: Specifies the main directory of the automatic diagnosis storage (ADR. Tracking file/warning log/Core File and accident file. The default value of this parameter is-LARGE_POOL_SIZE derived from ORACLE_BASE: Specifies the size (in bytes) of the heap allocated to a large pool-REMOTE_LOGIN_PASSWORDFILE: Specifies whether the Oracle software checks the password file. The default value is the interaction between the EXCLUSIVE database instance and ASM. 1. Create a file for the database Request. 2. The ASM foreground process creates a continuous operation directory (COD) entry and allocates space for the new file in the disk group. 3. The ASM database process receives the zone ing of the new file 4. The file is now open, and the database process directly initializes the file. 5. After initialization, the database process requests the creation of a file. This causes the ASM foreground process to clear the COD entry and mark the file as created. 6. If the file is submitted, the file will be closed implicitly. When I/O occurs in the future, the database instance needs to re-open the file. -- Database instances and ASM instances work together. The database instance must interact with ASM to map the database file to the ASM area. -- Database I/O is not transmitted through the ASM instance. In fact, the database directly performs I/O operations based on the ASM file. ASM instance: dynamic Performance view-the ASM utility uses the SQL language to access these tables to retrieve information containing only metadata-including many dedicated ASM-related views V $ ASM_ALIAS V $ ASM_ATTRIBURE V $ ASM_CLIENT V $ ASM_DISK V $ ASM_DISK_IOSTAT V $ ASM_DISK_STAT V $ ASM_DISKGROUP V $ ASM_DISKGROUP_STAT V $ ASM_FILE V $ ASM_OPERATION V $ ASM_TEMPLATE ASM system permission-the ASM instance does not have a data dictionary SYSASM--OSASM (asmadmin) --- all management permissions SYSDBA--OSDBA (asmdba) --- access data stored in ASM, with SYSASM permissions SYSOPER--OSOPER (asmoper) in the current version --- limited permissions, you can use A group of non-destructive alter diskgroup commands as well as start and stop Start and Stop an ASM instance using SQL * Plus $ sqlplys/as sysasm SQL> startup ALTER DISKGROUP... MOUNT; SQL> shutwon abort [OPEN]-FORCE: Issue the SHUTDOWN ABORT-MOUNT or OPEN: MOUNT the disk group specified in the ASM_DISKGROUPS initialization parameter to the ASM instance before it restarts.-NOMOUNT: start the ASM instance without loading any disk group-RESTRICT: Start the instance in restricted mode. RESTRICT can be used in combination with MOUNT/NOMOUNT/OPEN (in restricted mode, database instances cannot operate on disks) [SHUTDOWN]-NORMAL (default off mode ): ASM unmounts all the disk groups and closes the ASM instances. Wait until the SQL operation is completed and the connected user is disconnected from the instance. New connections-IMMEDIATE or TRANSACTIONAL: ASM will not wait until the ongoing SQL operation is completed before detaching all disk groups and closing the instance, and will not wait until the user currently connected is disconnected. -ABORT: