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A few days ago, I encountered a case, a 11.2.0.4 three-node Oracle RAC database on RHEL 6.6 , when trying to login to the database instance using sqlplus “/ as sysdba” on the third node, It’s very slow, and vmstat show that there is a very large swap in and out, but there is still a lot of memory free space
If kernel can not find memory to allocate when it’s needed, it puts in-use user data pages on the swap-out queue, to be swapped out. If the Virtual Memory (VM) cannot allocate memory and canot swap out in-use memory, the Out-of-memory killer may begin killing current userspace processes.
这次预警主要是因为AIX的新特性Flash cache device相关的bug引起的ORACLE 数据库可用性风险， 虽然坑是AIX挖的，但是对于装数据库和巡检(RDA），DBA及客户就是直接受害者。 OracleDBA在使用RDA巡检运行在AIX 7.1 、7.2上使用了ASM 的数据库时可能会把库查死
建议在SLSE 12或以后的版本，或LINUX 7等以后的版本时，先了解一下系统变化，至少在安装RAC时， 把DefaultTasksMax修改加入到安装方档中去， 可能Oracle 在以后的安装文档或最佳实践中会增加该内容。
dcli 为Oracle Exadata Machine中提供的管理cell的工具，全名 Distributed Command Line Interface，在Exadata， Exalogic， Exalytics等系列一体机都自带这个工具, 该工具是一套python脚本，可以用文本工具直接查看编辑， 在当前的IT管理中批量管理几百台机器已不是什么稀奇的事， 所以在日常一些批量共性的常规检查和运维就需要一种维护工具自动实现或者叫自动化运维工具， 当前较流行的有puppet和ansible 产品
因为我国是东八时区(UTC+8),所以我国将在北京时间2017年1月1日的7时59分59秒也会做闰秒调整和全球同步，到时会出现7:59:60的特殊现象。对时间敏感的系统不可忽略,除了航天系统,我们的数据库系统应该也要做好检查, 润秒有可能会使OS Reboot,应用HANG, Clusterware restart影响.
整理的一个清理Oracle数据库监听日志的脚本，可以部署到监听进程的owner用户的crontab中(RAC通常是grid, 单实例通常是oracle), 实现的是监听日志大于1GB时，归档监听日志文本格式的文件如listener.log ，自动压缩保存， 后期循环自动覆盖， 11G 引入的ADR, XML格式的文件19c前也无法自动清理，这个shell 目前是自动rm 7前天的， 关于19c 的日志自动清理后期会分享
最近遇到了两起数据库连接数不足的问题， 通常都会预留一些会话增加的情况， 但在一些特殊情况下如连接风暴(logon storm)， 如果在监听中没有做rate限流，对数据库来说
巨大的冲击可能会导致数据库Hang 或 ora-20 或ora-18 错误。
I have a ORACLE db server on hp-ux, i want to execute a sql script file in sqlplus using “@” , get some error. but I use “start” sql file in sqlplus ,it work fine for me. now I have been resolved this error, just shared here. SQL> @uptime SP2-0042: unknown command “uptime” – … Read more
The MegaRAID Storage Manager includes both GUI (MSM) and The megacli tool is used for managing the controller via the command-line interface, text based tools (MegaCLI) to monitor and manage the disk array.
this is shell script to backup mysql database, using mysqldump to dump all databases into separate files, and encrypt backup file using zip password option, Generate a collective file using tar, ftp to ftp server, to send email to DBA .
Next, let’s create the mysql user and group: groupadd mysql useradd -g mysql mysql create mysql soft and data files store dictroy. and install mysql mkdir -p /data/mysql tar zxvf mysql-5.5.36-linux2.6-x86_64.tar.gz mv mysql-5.5.36-linux2.6-x86_64 /data/mysql/ cd /usr/local ln -s /data/mysql/mysql-5.5.36-linux2.6-x86_64/ mysql scripts/mysql_install_db –user=mysql or (./mysql_install_db –user=mysql –basedir=/usr/local/mysql –datadir=/usr/local/mysql/data) Modify File and Directory Permissions cd /data/mysql/ chown … Read more
Oracle has the BBED utility (block browser and editor) is is all releases of Oracle, from Oracle7 to Oracle10g,In Oracle 11g, BBED becomes unavailable but if you search in the ins_rdbms.mk makefile,…
一个不错的oracle AWR 报告本地文件格式化chrome浏览器插件，看似用js完成，有一些特性非常不错，拿出来分享，作者Tyler Muth –观看 需要翻墙 视频介绍 下载 下载地址1 下载地址2 安装方法 1，下载AWR-Format.crx文件 2，打开chrome 谷歌浏览器，我这里版本是28，点击右上角的按钮或显示菜单，找工具–扩展程序 打开扩展程序页面 3，用鼠标把1 下载的文件托进浏览器的这个页面，增加插件，默认是启用，勾选插件下的“允许访问文件网址” 4，右击本地的AWR html文件，使用google chrome 打开，体验一下吧
Prior to 10g you can use a unix debugger like gdb, adb or dbx to attach to a shadow process and dump the system state using the function ksudss which is the subroutine in the Oracle source code which does the same.
Each time your program performs a function call, information about the call is generated. That information includes the location of the call in your program, the arguments of the call, and the local variables ..
shell统计linux系统中每个程序的内存使用情况，因为内存结构非常复杂，不一定100%精确，
•What is zabbix ?
•What can it monitor?
•Structure of ZABBIX and Componentes
[oracle@db231 ~]$ ./adr_purge
INFO: Purge started at Thu May 16 07:35:32 CST 2013
INFO: adrci purge started at Thu May 16 07:35:32 CST 2013
INFO: adrci purging diagnostic destination diag/tnslsnr/db231/listener
INFO: purging ALERT older than 90 days …
INFO: purging INCIDENT older than 30 days …
Creates a backup directory if required, works out the ASM SID, renames the previous entry, then loops round backing up the metadata data for each diskgroup. It also lists each file backed up which is quite helpful. Finally it creates error checking and a log and error file outputs [grid@rac1 ~]$ cat asm_metadata_bk.sh #!/bin/sh # … Read more