Today's content:
1, computer performance
2, the operating system to start
2, the basic format of Linux commands
3, Linux basic commands to use
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1, computer performance
1) :( scale cluster strength in numbers) in accordance with the cluster structure can be divided into the following categories and functions:
a, cluster load balancing: the front end typically by one or more load balancing cluster load balancer running on the workload distribution to the rear end of a group of servers, the entire system to achieve high performance and high availability.
b, high availability clustering: generally refers to the case when there is a cluster node fails, the task of which will be automatically transferred to other normal nodes.
C, High Performance Cluster (application layer): HPC clusters using computing tasks assigned to a different cluster of computing nodes children increased computing power, and thus is mainly used in the field of scientific computing. The more popular HPC Linux operating system and other free software to complete parallel computing. (Hadoop cluster = Map reduces + HDFS).
d, Network Computing: Grid computing is one kind or a mesh cluster with the cluster very relevant art. The main difference with the traditional grid computer cluster is a group of related grid connection is not trusted, it operates more like a computing utility, rather than a stand-alone computer. Also, the grid is usually more than a cluster of different types of computer support collections.
2) Scale up: Application Migration (never suggested vertical expansion way to improve computer performance).
2, the operating system to start
Extended: chkonfig
Role: Specifies the service turned on that level, start or shutdown
3, the basic format of Linux commands
Command [options] [parameters]
[]: Brackets representatives dispensable; to specify a particular command functions to achieve
<>: Command execution object represents, if not added <> can not be omitted representatives
Long integer option
短选项 *短选项可以合并，而长选项不能合并
4、Linux命令的基本使用
ls //显示文件信息
-l //ll 查看文件的详细信息（属性）
-i //inode（属性）[索引信息]
-h //human 人类可读 显示文件大小
-lh:
-F //显示文件后面的标记（用来区分文件类型）
-r //倒序显示文件内容
-a //显示所有文件（包括隐藏文件）
pwd //显示当前路径
$pwd 默认有一个这个环境变量，了解即可
cd //切换到目标目录
~ 当前用户的家目录（/root /home）
. 当前目录（以.开头的文件为隐藏文件）
.. 当前目录上一级目录
- $OLDPWD存放上一次经过的目录
touch //修改时间戳
-a 修改访问时间
-m 修改修改时间
-t 修改成什么时间
-c 修改文件mtime，如果文件不存在，不创建该文件
mkdir //创建文件夹
-p 递归创建多级子目录
-v 详细显示创建过程
rm //删除
-f 强制删除
-i 询问是否删除该文件默认命令（alias rm=rm -i）
-r 删除目录文件
扩展：
1、默认情况下不适用rm删除目录，--rmdir，rmdir只能删除空目录
*2、我们将需要删除文件或目录移动到/tmp目录下即可，/tmp目录为临时文件目录，30天未被访问的文件会自动删除
3、如果必须删除一些文件，通过find命令匹配出来后，再行删除
find /-name abc |xargs rm
find /-name abc -exec rm {}\