记录云计算中心日常工作关于系统运维,虚拟化云计算,数据库,网络安全等各方面问题。
How to upgrade or update kernel of the CentOS to Latest stable KernelThe kernel is the core of the operating system, and runs the CPU, manages system memory, controls access to disk drives, and contains device drivers that enable you to interact with the system and use the hardware and peripherals attached to the  computer.Naturally, kernel update  appeals most system administrators who are responsible for wringing the most performance and benefit out of their existing hardware and software. In some cases, rebuilding the kernel(kernel upgrade or kernel update) is required in order to support new hardware that is not supported, or that is poorly supported, by your system’s existing kernel.Check the current kernel of the system by using uname –r option.[root@localhost ~]# uname -r 3.10.0-327.el7.x86_64 After you have determined the version of the kernel you are currently running, the next step is to obtain the latest version of the k...
 
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Install GFS2 in CentOS 6.5

发表者:admin分类:应用服务2017-07-13 15:23:28 阅读[680]
Install GFS2 In CentOS 6.5 In computing, the Global File System 2 or GFS2 is a shared disk file system for Linux computer clusters. GFS2 differs from distributed file systems (such as AFS, Coda, InterMezzo, or GlusterFS) because GFS2 allows all nodes to have direct concurrent access to the same shared block storage. In addition, GFS or GFS2 can also be used as a local filesystem. GFS  has no disconnected operating-mode, and no client or server roles. All nodes in a GFS cluster function as peers. Using GFS in a cluster requires hardware to allow access to the shared storage, and a lock manager to control access to the storage. The lock manager operates as a separate module: thus GFS and GFS2 can use the Distributed Lock Manager (DLM) for cluster configurations and the “nolock” lock manager for local filesystems. Older versions of GFS also support GULM, a server based lock manager which implements redundancy via failover.Here is my t...
Active Session History (ASH) performed an emergency flush 告警日志信息 Tue Sep 15 14:29:27 2015 Active Session History (ASH) performed an emergency flush. This may mean that ASH is undersized. If emergency flushes are a recurring issue, you may consider increasing ASH size by setting the value of _ASH_SIZE to a sufficiently large value. Currently, ASH size is 67108864 bytes. Both ASH size and the total number of emergency flushes since instance startup can be monitored by running the following query: select total_size,awr_flush_emergency_count from v$ash_info; 执行告警日志中查询语句 SYS@hkprdbuat> select total_size/1024/1024 MB,awr_flush_emergency_count from v$ash_info; MB AWR_FLUSH_EMERGENCY_COUNT ---------- ------------------------- 64   3 查询当前大小 select x.ksppinm name,y.ksppstvl value,y.ksppstdf isdefault,decode(bitand(y.ksppstvf,7),1,'MODIFIED',4,'SYSTEM_MOD','FALSE') ismod,       decode(bitand(y.ksppstvf,2),2,'TRUE','FALSE') isadj from sys.x$ksp...
大家都知道Linux平台上,可以通过history命令查看最近所执行过的命令,但history命令默认所显示的只有编号和命令的,只知道命令是最近所执行的,但不知具体执行的日期、时、分、秒,有时给寻找证据带来不便,例如如下显示情况:352  exit353  history354  vi /etc/profile355  history下面就来讲一下,如何让history命令显示最近所执行过的命令的具体执行时间与修改命令保存行数为10000。步骤如下:1、以ROOT用户编辑/etc/profile文件,在里面加入下面内容(我一般习惯在最末尾加):sed -i 's/HISTSIZE=1000/HISTSIZE=10000/g' /etc/profileecho 'export HISTTIMEFORMAT="%Y%m%d-%H%M%S: “’ >> /etc/profile注意:在末尾的“引号”与“S”之间,加入一位空格,将日期时间和历史命令用空格相隔开来。2、退出系统重新登陆注意:在第2步以前所执行的历史命令,在重新登陆后,执行时间全部分显示为第二步执行时的时间,后面所执行的命令,才会显示正确的实际执行时间。
安装CentOS 6.6出现Disk sda contains BIOS RAID metadata 今天在安装CentOS 6.6的时候,当进到检测硬盘步骤的时候,总是过不去,报错如下:Disk sda contains BIOS RAID metadata, but is not part of any recognized BIOS RAID sets. Ignoring disk sda服务器有两块硬盘sda、sdb,都有这样的提示;这种情况在安装Ubuntu,SUSE都有类似的情况,只是提示不太一样而已。          故障原因:因为服务器上有两块盘,之前做过Raid1,且安装过Windows操作系统,现在直接改装CentOS不认磁盘,肿么办?          插入安装光盘,进入CetnOS 6.6安装选择菜单时,按“TAB”键,会进入到Linux的命令行模式,然后在启动命令行的后面添加 nodmraid(注意前面有个空格)并按“回车”键。加nodmraid命令是为了关掉阵列;接下来进入安装过程中检测硬盘时就会发现硬盘找到了;
Nginx配置文件主要分成四部分:main(全局设置)、server(主机设置)、upstream(上游服务器设置,主要为反向代理、负载均衡相关配置)和 location(URL匹配特定位置后的设置),每部分包含若干个指令。    main部分设置的指令将影响其它所有部分的设置;server部分的指令主要用于指定虚拟主机域名、IP和端口;upstream的指令用于设置一系列的后端服务器,设置反向代理及后端服务器的负载均衡;location部分用于匹配网页位置(比如,根目录“/”,“/images”,等等)。    他们之间的关系式:server继承main,location继承server;upstream既不会继承指令也不会被继承。它有自己的特殊指令,不需要在其他地方的应用。######Nginx配置文件nginx.conf中文详解##### #定义Nginx运行的用户和用户组 user www www; #nginx进程数,建议设置为等于CPU总核心数。 worker_processes 8; #全局错误日志定义类型,[ debug | info | notice | warn | error | crit ] error_log /usr/localinx/logs/error.log info; #进程pid文件 pid ...
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最近一台新上线的Oracle 数据库在警告日志文件中(alert.log)持续出现如下错误:Tue Jul 18 23:09:22 2006WARNING: inbound connection timed out (ORA-3136)Tue Jul 18 23:09:23 2006WARNING: inbound connection timed out (ORA-3136)Tue Jul 18 23:09:25 2006WARNING: inbound connection timed out (ORA-3136)Tue Jul 18 23:09:30 2006WARNING: inbound connection timed out (ORA-3136)Tue Jul 18 23:12:15 2006WARNING: inbound connection timed out (ORA-3136)同时在sqlnet.log中记录了如下错误:VERSION INFORMATION:TNS for Linux: Version 10.2.0.2.0 - ProductionOracle Bequeath NT Protocol Adapter for Linux: Version 10.2.0.2.0 - ProductionTCP/IP NT Protocol Adapter for Linux: Version 10.2.0.2.0 - ProductionTime: 19-JUL-2006 11:25:26Tracing not turned on.Tns error struct:ns main err code: 12535TNS-12535: TNS:operation timed outns secondary err code: 12606nt main err code: 0nt secondary err code: 0nt OS err code: 0Client address: (ADDRESS=(PROTOCOL=tcp)(HOST=192.168.1.123)(PORT=58147))这是和网络连接相关的一个错误,Metalink上...
ISCSI重启或断网假死,挂载后LV无设备或系统找不到分区解决方法。Centos6主机采用ISCSI+LVM+XFS分区来保存数据。 ISCSI存储或客户端出现断网或ISCSI程序假死,出现这种情况后,为保证数据不出意外损失。先关闭使用存储的运行程序,然后将XFS的分区取消挂载。#:  umount /data然后将ISCSI取消登陆。#:  iscsiadm -m node --targetname iqn.2016-11.dev.iscsi-target:data4 --portal 192.168.1.202 --logout然后查看分区信息,ISCSI相关信息是否还存在。#:  fdisk -l#:  lvs最后再重新挂载ISCSI。[root@cfs1 ~]# :    iscsiadm -m discovery -t sendtargets -p 192.168.11.202[root@cfs1 ~]# :    iscsiadm -m node --targetname iqn.2016-11.dev.iscsi-target:data1 --portal 192.168.11.202 --login完成后,检查ISCSI设备与LVM设备是否正常。[root@cfs1 ~]# :  fdisk -l[root@cfs1 ~]# : vgscan[root@cfs1 ~]# :  lvscan如果正常,fdisk -l 查看时会显示XFS分区信息,如下图。正常情况分区会显示,如图中: Disk /dev/mapper/vg_data-lv_data。如果没有分区,可能是lv 没有正常激活,显示为inactive 。[root@c...
Microsoft SQL Server 数据库的 JDBC URL 格式对于 Microsoft SQL Server 数据库,可以使用以下示例 JDBC URL 作为模型:■    按主机名连接到默认的(未命名的)SQL Server 实例:jdbc:sqlserver://host;databaseName=database■    按主机名和实例名连接到已命名的实例:jdbc:sqlserver://host;instanceName=instance;databaseName=database■    按主机名和端口连接到 SQL Server:jdbc:sqlserver://host:port;databaseName=database■    按端口连接:jdbc:sqlserver://localhost:1422;databaseName\=VIM_VCDB(要单独传递的用户名、密码和数据库类型)■    使用集成安全性连接到本地服务器:jdbc:sqlserver://localhost\\SQLEXP_VIM;databaseName=VIM_VCDB;integratedSecurity=true■    不使用集成安全性连接到本地服务器:jdbc:sqlserver://localhost\\SQLEXP_VIM;databaseName\=VIM_VCDB (要单独传递的用户名、密码和数据库类型)默认情况下,Microsoft SQL Server 的 VMware vCenter Server JDBC 配置可能无法使用直接 IPv6 地址。必须使用下列形式之一:■ &nb...
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