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Hot-spare and standby hot-spare drives supply additional protection to a RAID configuration. When you select the RAID level for your configuration, consider the following:[@more@]RAID level Can use a hot spare? Can use a standby hot spare? 0NoNo1YesYes1EYesYes5YesYes5E *YesYes5EE *YesYes6YesNo00NoNo10YesYes1E0YesYes50YesYes60YesNo* RAID level-5E and RAID level-5EE integrate a distributed hot-spare drive, but also can use traditional hot-spare and standby hot-spare drives. If a physical drive fai

总结一下，还是shell比较方便－ －[@more@]Microsoft SQL ServerEven if you don't know much about Microsoft's SQL Server, you will probably have heard of the extended stored procedure xp_cmdshell. Normally, only those with sysadmin privileges can run xp_cmdshell , but over the past few years, several vulnerabilities have come to light that allow low-privileged users to use it. xp_cmdshell takes one parameter—the command to execute. This command typically executes using the security context of the a

使用root直接登录，发现上面的失败信息[root@nh109-12 ~]# mysqlERROR 1045: Access denied for user: 'root@localhost' (Using password: NO)检查root的home目录下，发现没有.my.cnf，添加完毕，重新登录ok[root@nh109-12 ~]# more .my.cnf[mysqladmin]password = 'pVRRD9uJC'user= root[client]password = 'pVRRD9uJC'port = 3306socket = /tmp/mysql.sock[@more@]

RAC的bug还真多,早上刚和taobao的弟兄说完,下午就中招[@more@]根据测试的需求修改了process,然后重起了各个节点,结果重起完发现一个节点上n多吃cpu的process,看了下都是QMNC相关的.pstack和oradebug看了内容，查了下metalink,bug。。。要到10204修正，好在问题不大可以通过重起解决，开发的偶bs乃，改啥参数。。。

具体版本为10203,发现一台当机后,vip漂移到别的节点上,但是telnet该vip地址1521端口不通,netstat -nl| grep 1521发现oracle只监听了本结点实际ip和vip的1521端口，没有对漂移过来的vip的1521监听。[oracle@NHDB4 orcl]$ netstat -nl | grep 1521tcp 0 0 222.73.121.6:1521 0.0.0.0:* LISTEN tcp 0 0 192.168.0.6:1521 0.0.0.0:* LISTEN 检查listener.ora文件发现oracle生成listener.ora可能发生问题原来文件：# listener.ora.nhdb1 Network Configuration File: /u01/app/product/10.2.0/db_1/network/admin/listener.ora.nhdb1# Generate

如果在asm中新建一个名为arch的归档目录，在RMAN中使用BACKUP ARCHIVELOG ALL FORMAT=‘X’ DELETE INPUT的话会导致asm自动删除这个目录（同样的使用asmcmd删除某个目录中所有文件也会导致自动删除该目录）接下来的归档就会挂起。要注意这点，可以在这个目录中添加一个空目录来防止[@more@]

reverse index 对于 MAX/MIN操作的影响[@more@]http://xzh2000.itpub.net/post/96/38200这是对于主键MAX/MIN索引进行的处理，但是发现如果主键使用了reverse index，虽然执行计划同样是full index scan。但是会进行全部索引块的扫描。对于业务可能有影响

[@more@]很多人问数据库打补丁失败，或者是我如何知道这个版本修复的bug，其实都在下载的包中，有buglist.htm和patchnote.htm以及readme.htm 在打补丁前看完就可以保证出现情况可以处理了