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lsdg中的Usable_file_MB 为什么是负值?Negative Values of USABLE_FILE_MB Due to the relationship between FREE_MB, REQUIRED_MIRROR_FREE_MB, and USABLE_FILE_MB, USABLE_FILE_MB can go negative. Although this is not necessarily a critical situation, it does mean that: Depending on the value of FREE_MB, you may not be able to create new files. The next failure may result in files with reduced redundancy. If USABLE_FILE_MB becomes negative, it is strongly recommended that you a

Provide a smooth and repeatable procedure to resize Exadata Disk Groups without re-installation or system outage. CAUTION 1: DO NOT TRY TO RESIZE THE DISK, WHEN DISK GROUP’S SPACE IS EXHAUSTED. You need minimum free space of “required_mirror_free_mb” for these methods to work. Use the following SQL to check the current space usage. SQL> select name, total_mb, free_mb, required_mirror_free_mb from v$asm_diskgroup; Note: Result of the query for “free_mb” need to be grea

Actually the question is “What happens when ASM has lost two disks in different failgroups when redundancy is normal?”[@more@]Actually the question is “What happens when ASM has lost two disks in different failgroups when redundancy is normal?”We’re sure that there will be no problem if we lose all of the disks in a single failgroup but in order to answer the question we have to understand how mirroring works in ASM.In normal redundancy, mirror of each extent is written to another disk in

A collection of facts on configuration and and diagnostic of Oracle ASM.[@more@]Contents: ASM Metadata and Internals ASM metadata, V$ and X$: X$KFFXP (metadata, file extent pointers) Example - find location of ASM files extents using x$kffxp X$KFDAT (metadata, disk-to-AU mapping table) Example2 - list allocation units of a given file from x$kfdat Example3 - list extents belonging to voting disk in ASM (11gR2) Example4 - from strace data of an oracle user proce

ASM Diskgroup Can Not Be Shown When Creating Database With DBCA在安装oracle 11g R2 RAC的时候，有时候会遇到在用DBCA建立数据库时使用ASM作为文件存储，看不到相关的ASM diskgroup 组的问题。，用GRID用户，使用ASMCA建立相关的disk group，在resource组里也显示正常。这个问题遇到过几次。最近一次是由于grid 用户目录下oracle 执行文件没有设置成S。以前安装时都是oracle 自动设置，支持不知道为什么没有改变。可能是由于我原来安装的是11.2.0.1，支持改变成11.2.0.2.有什么地方没清除干净等原因。解决问题一般有如下解决方

Setup SCAN listener and Clients to use SCAN listener to connect to 11gR2 RAC using SCAN.[@more@] Verify SCAN Listener Configuration on Server After grid installation is completed you can verify the SCAN Listener configuration on your server - •At the $GRID_HOME/network/admin directory you will have two listener related files. -rw-r--r-- 1 grid oinstall 887 Jul 13 09:33 listener.ora -rw-r--r-- 1 grid oinstall 375 Jul 13 09:33 endpoints_listener.ora example of listener.ora LISTENER_SCAN

Document to show 11.2 Scan and Node TNS listener examples for RAC, along with client trace connection, showing possible route taken to database from client.[@more@] SolutionExample for 2 Node cluster with 2 Scan listeners running, with following details: Ipaddress Hostname-------------- -------------------------------------Scan Addresses:11.111.111.11 netrac-scan netrac-scan.uk.oracle.com22.222.222.22 netrac-scan netrac-scan.uk.oracle.comNode Addresses:12.345.678.111

How To Setup UDEV Rules For RAC OCR And Voting Devices On SLES10, RHEL5, OEL5, OL5 [ID 414897.1] 1. Create The New UDEV Rules 1.1 Create UDEV Permission Rule Prior Up-To Version 11.1.0.7 1.2 Create UDEV Permission Rule For Version 11.2 And Later 2. Restart The UDEV Service[@more@]Applies to:Linux OS - Version: 2.6.18-8 to 2.6.21Oracle Server - Enterprise Edition - Version: 10.1.0.2 to 11.2.0.2.0 [Release: 10.1 to 11.2]Linux x86Linux x86-64Linux Itanium***Checked for re

GoalThe goal of this document is to provide checklist when connection through 11gR2 Grid Infrastructure (CRS) SCAN name to database fails. Solution Troubleshooting StepsWhen client program connects to RAC database through SCAN name, SCAN listener will accept t he request and redirect the connection to local listener. To identify connection issue, first try to connect to each local listener through node VIP, then try each SCAN listener through each SCAN VIP. [@more@]To test throug

在网络上看到这篇文章，写的不错。特转载在自己的blog里，需要时查看。文章中红色字体部分，写的不错。对于带绑定变量的sql语句的执行计划，用set autotrace on 显示的不对。使用 select * from table(dbms_xplan.display_cursor); 进行执行计划的查看这个语句是我们在ACS测试过程总经常使用的sqlselect child_number, executions, buffer_gets, is_bind_sensitive, is_bind_aware,IS_SHAREABLE S,plan_hash_value from v$sql where sql_id = 'gsmm31bu4zyca';[@more@]Adaptive Cursor Sharing（ACS）是又一个大胆而吸引人的11G新特性。说

一、概述Oracle提供两种不同的复制方法：多主复制（multimaster replication）和物化视图复制（materialized view replication）。还可以通过两种复制的组合构成混合复制。本文主要描述物化视图复制，由于物化视图复制中的主站点就是多主复制中的站点，因此也会对相应的多主复制中涉及到的内容作相应的说明。[@more@]二、物化视图的概念和体系结构Oracle的物化视图主要用在两个方面：高级复制和数据仓库。在高级复制环境中，物化视图用于复制数据到非主体站点。在数据仓库环境中，物化视图用于对代价昂贵的查询进行缓存。1．物化视图是什么

注意repository数据库中的sysman用户密码不要改，不然oms会连接不上：[oracle@bin]$ ./emctl status omsOracle Enterprise Manager 10g Release 10.2.0.1.0 Copyright (c) 1996, 2005 Oracle Corporation. All rights reserved.Oracle Management Server is not functioning because of the following reason:Connection to the repository failed. Verify that the repository connection information provided is correct.于修改sysman的密码，可以参见metalink的这个文章（ID 270516.1）：[@more@]To change the SYSMAN password: 1.

GoalStep by step guide on how to create a physical standby database using RMAN DUPLICATE �FROM ACTIVE DATABASE command without shutting down the primary and using primary active database files (No need to take backup)Database Name :- chicagoPrimary db_unique_name :- chicagostandby db_unique_name :- Boston[@more@]Solution1.Make the necessary changes to the primary database. a. Enable force logging.b. Creating the password file if one does not exist.c. Create standby redologs.d. Modify the

PurposeThis document has been created with step-by-step instructions on how to create a Data Guard Physical Standby configuration manually without the aid of the broker. All steps are derived from the 10GR2 documentation. It is assumed that the reader is aware of the features of RDBMS such as SPFILE usage, storage such as ASM, OCFS. Please avail these features where appropriate and test them before implementing in production.[@more@]Creating a 10gr2 Data Guard Physical Standby database with Real

GoalThis document offers step by step procedure to create physical standby from ASM primary.Database Name :- chicago Primary db_unique_name :- chicago standby db_unique_name :- Boston Primary Hostname :- raca.idc.oracle.com standby Hostname :- core1.idc.oracle.com [@more@]Solution1. Enable Force Logging, SQL> ALTER DATABASE FORCE LOGGING; Database altered. 2. On the primary node, create a staging directory. For example: [oracle@raca chicago]$ mkdir –p /home/oracle/stage 3. Create the same ex

PurposeThis Article cover the detailed steps for creating a physcial standby database on a normal file system using RMAN for a primary database in ASM. [@more@]Step-By-Step Guide To Create Physical Standby On Normal File System For ASM Primary using RMANOverviewHere the Standby database can be created using the following 2 methods1. Normal Restore and Recovery using RMAN.2. Creating a Duplicate database for Standby using RMAN.Method 1 + Perform the backup of the ASM primary database ( Datafiles,

GoalStep by Step Guide on How to Create Logical Standby [@more@]SolutionPrerequisite 1 : Before setting up a logical standby database, ensure the logical standby database can maintain the data types and tables in your primary database. See Appendix C of the dataguard documentation for a complete list of data type and storage type considerations. 2 : Ensure Table Rows in the Primary Database Can Be Uniquely Identified. 2.1 : Find Tables Without Unique Logical Identifier in the Primary Database. U

Tablespace created.System altered.对应的trace文件中记录的报错内容大同小异。SQL> alter system set db_file_name_convert='/u01/app/oracle/oradata/secdb/','/u01/app/oracle/oradata/SECDG/datafile/' scope=spfile;SQL> shutdown immediate;ORA-01109: database not openDatabase dismounted.Total System Global Area 314572800 bytesFixed Size 1219184 bytesVariable Size 96470416 bytesDatabase Buffers 213909504 bytesRedo Buffers 2973696 bytesSQL> alt

Orale10g OEM Grid Control是Oracle公司提供的一种企业级数据库（数据库节点数在几十台以上的规模）部署，管理和监控的解决方案，较之10g之前的oem有了本质的区别，它基本上重写了所有的代码，变成了一种基于web的架构，使用户无需再在客户机上安装笨重的java 控制台了。负责维护的数据库数据增长到接近500台，因此在管理上采用了企业级的Oracle10g oem grid control来进行日常的管理和维护。在使用过程中发现它的功能比想象中强大的多，管理的集成性作的也非常好，以下是笔者在实际使用中积累的文档和一些心得体会。If you want to Enter

说明：觉得这篇文章写的不错，特此应用（他把DWBW,LGWR,CKPT 进程间的关系用一个图非常好的做了描述）如大家所知，用户提交的数据并非直接写入数据文件，这中间有一个复杂的处理过程，如下图所示：大致描述了数据写过程中的处理逻辑[@more@]写数据库缓存：单数据库缓存的写过程看起来很简单，但是其实际过程相当复杂，大家务必要注意。最基本的在写数据库缓存之前，肯定会先涉及到读，比如你要更新一个表的数据，那么它会首先查找你要更新的数据是否已经存在于数据库缓存，如果不存在，就需要先将其从数据文件中读取出来，而这个读取又有可