Oracle Database 环境整改建议应对 Linux TCP SACK PANIC 内核安全高危漏洞 CVE-2019-11477

在 Linux 内核处理 TCP 网络数据的操作中发现了三个相关的安全漏洞。 其最严重的安全漏洞会被远程攻击者利用在运行受影响软件的系统上触发一个内核崩溃,从而影响到系统的可用性。对于安装现在运行oracle 数据库的环境,anbob建议禁用tcp_sack的方式解决SACK问题高危。

Troubleshooting kernel: EXT4-fs warning (device dm-0): ext4_dx_add_entry: Directory index full!

The following error message is displayed in the database host operating system log of a customer today.

kernel: EXT4-fs warning (device dm-0): ext4_dx_add_entry: Directory index full!

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Troubleshooting sqlplus logon instance slow and Swap usage high even memory is 50% free

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

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Troubleshooting Out-Of-Memory(OOM) killer db crash when memory exhausted

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.

Alert : 当在AIX 7.1/7.2使用AIX Flash Cache 读写/dev/pfcdd0时System crashes

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

Troubleshooting ORA-27300 ‘fork failed with status: 11’ on SLES12 (SUSE /Linux 7)

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。

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自动化运维工具之:dcli 批量管理主机

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

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Leap Second (闰秒) 在ORACLE环境的影响

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.

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Shell: To delete listener log file contains text and xml format (自动清理监听日志)

清理数据库监听日志的脚本 清理多个监听日志 清理文本和XML格式,自动判断 根据文本格式大小默认1GB 根据X […]

Shell: extract more from listener.log (分析oracle监听日志连接频率)

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。

Unable execute “@”(at) sql file in sqlplus on hp-ux issue

I have a ORACLE db server on hp-ux,  i want to execute […]

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How to use the MegaCLI Utility with your RAID Controller on your DELL PowerEdge Server in Linux. (在linux监控RAID信息)

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.

Shell script to backup MySQL database(备份MySQL 脚本)

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 .

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MySql 5.5 tar安装及sysbench 配置

Next, let’s create the mysql user and group: groupadd m […]

How to used the gdb (GNU Debugger) Collecting Hanganalyze and Systemstate Dumps on Linux systems(操作系统收集hanganalyze和systemstate)

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.

How to get call stack of oracle processes ?

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 ..

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SHELL:Find Memory Usage In Linux (统计每个程序内存使用情况)

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,

Install ZABBIX On Linux 5 监控安装配置(pdf)

•What is zabbix ?
•What can it monitor?
•Structure of ZABBIX and Componentes

script:purge ADR file

[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 …

Backup ASM metadata with shell

Creates a backup directory if required, works out the A […]

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