centos7 g?centos7点几哪个版本好用

大家好,今天小编来为大家解答centos7 g这个问题,centos7点几哪个版本好用很多人还不知道,现在让我们一起来看看吧!

centos 7 需要多大内存

最低1G,最好是2G以上。

CentOS查看内存方法:

grep MemTotal/proc/meminfo

grep MemTotal/proc/meminfo| cut-f2-d:

free-m|grep"Mem"| awk'{print$2}'

Free查看内存详解:

root@Linux/tmp]# free

第1行:

total内存总数: 4149156

used已经使用的内存数: 4130412

free空闲的内存数: 18744

shared当前已经废弃不用,总是0

buffers Buffer Cache内存数: 13220

cached Page Cache内存数: 2720160

关系:total= used+ free

第2行:

-/+ buffers/cache的意思相当于:

-buffers/cache的内存数:1397032(等于第1行的 used- buffers- cached)

+buffers/cache的内存数: 2752124(等于第1行的 free+ buffers+ cached)

扩展资料:

CentOS是一个基于Red Hat Linux提供的可自由使用源代码的企业级Linux发行版本。每个版本的 CentOS都会获得十年的支持(通过安全更新方式)。

新版本的 CentOS大约每两年发行一次,而每个版本的 CentOS会定期(大概每六个月)更新一次,以便支持新的硬件。这样,建立一个安全、低维护、稳定、高预测性、高重复性的 Linux环境。[1]CentOS是Community Enterprise Operating System的缩写。

CentOS7网络设置修复

服务器有两个网卡enp7s0和enp8s0   

服务器需要通过enp8s0和互联网联通,互联网为笔记本转接

通过centos7界面修改ip,失败;

通过centos7的网络配置文件/etc/sysconfig/network-scripts/ifcfg-enp8s0修改ip设置

设置如下:

1.启动 service network start报错,通过journalctl-xe查看如下

-- Defined-By: systemd

-- Support:

--

-- Unit fprintd.service has begun starting up.

12月 29 19:31:12 crrchost dbus-daemon[851]: dbus[851]: [system] Successfully activated service'net.reactivated.Fprint'

12月 29 19:31:12 crrchost dbus[851]: [system] Successfully activated service'net.reactivated.Fprint'

12月 29 19:31:12 crrchost systemd[1]: Started Fingerprint Authentication Daemon.

-- Subject: Unit fprintd.service has finished start-up

-- Defined-By: systemd

-- Support:

--

-- Unit fprintd.service has finished starting up.

--

-- The start-up result is done.

12月 29 19:31:12 crrchost fprintd[6685]: Launching FprintObject

12月 29 19:31:12 crrchost fprintd[6685]:** Message: D-Bus service launched with name: net.reactivated.Fprint

12月 29 19:31:12 crrchost fprintd[6685]:** Message: entering main loop

12月 29 19:31:18 crrchost polkitd[835]: Operator of unix-session:1 successfully authenticated as unix-user:windfarm to gain TEMPORARY authorization for action org.freedesktop.systemd1.manage-units for system-bus

12月 29 19:31:18 crrchost systemd[1]: Starting LSB: Bring up/down networking...

-- Subject: Unit network.service has begun start-up

-- Defined-By: systemd

-- Support:

--

-- Unit network.service has begun starting up.

12月 29 19:31:18 crrchost network[6693]:正在打开环回接口: [ 确定  ]

12月 29 19:31:18 crrchost network[6693]:正在打开接口 enp7s0:

12月 29 19:31:24 crrchost network[6693]:正在确定 enp7s0的 IP信息...失败:不存在链接。检查电缆?

12月 29 19:31:24 crrchost network[6693]: [失败]

12月 29 19:31:24 crrchost network[6693]:正在打开接口 enp8s0: RTNETLINK answers: File exists

12月 29 19:31:25 crrchost network[6693]: [ 确定  ]

12月 29 19:31:25 crrchost network[6693]: RTNETLINK answers: File exists

12月 29 19:31:25 crrchost network[6693]: RTNETLINK answers: File exists

12月 29 19:31:25 crrchost network[6693]: RTNETLINK answers: File exists

12月 29 19:31:25 crrchost network[6693]: RTNETLINK answers: File exists

12月 29 19:31:25 crrchost network[6693]: RTNETLINK answers: File exists

12月 29 19:31:25 crrchost network[6693]: RTNETLINK answers: File exists

12月 29 19:31:25 crrchost network[6693]: RTNETLINK answers: File exists

12月 29 19:31:25 crrchost network[6693]: RTNETLINK answers: File exists

12月 29 19:31:25 crrchost network[6693]: RTNETLINK answers: File exists

12月 29 19:31:25 crrchost systemd[1]: network.service: control process exited, code=exited status=1

12月 29 19:31:25 crrchost systemd[1]: Failed to start LSB: Bring up/down networking.

-- Subject: Unit network.service has failed

-- Defined-By: systemd

-- Support:

--

-- Unit network.service has failed.

--

-- The result is failed.

12月 29 19:31:25 crrchost systemd[1]: Unit network.service entered failed state.

12月 29 19:31:25 crrchost systemd[1]: network.service failed.

12月 29 19:31:25 crrchost polkitd[835]: Unregistered Authentication Agent for unix-process:6669:319312(system bus name:1.263, object path/org/freedesktop/PolicyKit1/AuthenticationAgent, locale zh_CN.UTF-8)(d

3.systemctl status network.service查看如下:

● network.service- LSB: Bring up/down networking

  Loaded: loaded(/etc/rc.d/init.d/network; bad; vendor preset: disabled)

  Active: failed(Result: exit-code) since六 2018-12-29 18:38:17 CST; 1min 24s ago

   Docs: man:systemd-sysv-generator(8)

  Process: 909 ExecStart=/etc/rc.d/init.d/network start(code=exited, status=1/FAILURE)

12月 29 18:38:06 crrchost systemd[1]: Starting LSB: Bring up/down networking...

12月 29 18:38:06 crrchost network[909]:正在打开环回接口: [ 确定  ]

12月 29 18:38:06 crrchost network[909]:正在打开接口 enp7s0:

12月 29 18:38:12 crrchost network[909]:正在确定 enp7s0的 IP信息...失败:…?

12月 29 18:38:12 crrchost network[909]: [失败]

12月 29 18:38:17 crrchost network[909]:正在打开接口 enp8s0: [ 确定  ]

12月 29 18:38:17 crrchost systemd[1]: network.service: control process exi...=1

12月 29 18:38:17 crrchost systemd[1]: Failed to start LSB: Bring up/down n...g.

12月 29 18:38:17 crrchost systemd[1]: Unit network.service entered failed...e.

12月 29 18:38:17 crrchost systemd[1]: network.service failed.

Hint: Some lines were ellipsized, use-l to show in full.

1.参考网络方法停用NetworkManager,依旧报错

   systemctl stop NetworkManager

    systemctl disable NetworkManager

2.比对两个网卡的MAC地址和配置文件的MAC地址

   a.查看mac地址配置,ipconfig

   b.查看配置文件中的macd地址是否匹配,ifcfg-enp8s0和ifcfg-enp7s0,

    按照网络方法增加一行HWADDR=ipconfig查询到的对应网卡MAC地址;

   c.重启network服务依旧报错;

3.通过GUI界面查看网络,提示“系统的网络服务与此版本的网络管理器不兼容”

  这与之前停掉NetworkManager有关,此处不表;

4.因为ifcfg-enp7s0实际上没有插网线,修正其配置文件如下:

   ONBOOT=no

  重新启动服务后网络正常;

5.检查网络

1.network和NetworkManager不同,通过界面和通过配置文件,可能会导致配置混乱,且NetworkManager有些程序不支持,需要停用;

2.BOOTPROTO=none虽然可以表示静态ip,但是如果要启用,必须设置其为

BOOTPROTO=static或BOOTPROTO=dhcp

3.一个网卡没哟被启用,也就是没有设置动态ip或静态ip,是无法被初始化的,不能设置ONBOOT=yes

In Centos7.0 disabling NetworkManager will leave a dhcp client running configured for NetworkManager. This causes the error message RTNETLINK answers: File exists when the network service is started.

The stale dhclient process has the additional"benefit" that when the lease expires your dhclientwill choke, since it cannot reach NetWorkManager, thus removing your IP address.

If you grep for it, you will see that it points to a NetWorkManager configuration file.

[root@host~]# ps-ef| grep dhc

root    1865  792  0 Apr28?     00:00:00/sbin/dhclient-d-sf\

/usr/libexec/nm-dhcp-helper-pf/var/run/dhclient-eno1.pid-lf\

/var/lib/NetworkManager/dhclient-c96e56d3-a4c9-4a87-85ca-93dc0ca268f2-eno1.lease\

-cf/var/lib/NetworkManager/dhclient-eno1.conf eno1

So what you can do is kill the dhclient and only then start your network service.

Centos7中systemd-journald占用内存过高问题

环境介绍

问题发生在CentOS-7.2版本的环境下。

现象描述

systemd-journald进程的内存占用率异常升高。

问题排查与原因分析

首先,通过top命令查看内存消耗情况,发现systemd-journald进程内存占用高达7.6G,显著影响系统性能。

进一步,查阅systemd-journald服务的说明,了解到其主要功能是收集并存储系统登录信息。

通过配置文件检查,发现默认存储参数未设置,系统使用的是自动配置。默认情况下,当存储文件不存在时,系统会将信息暂存于内存中。

问题总结

频繁的用户登录登出活动导致大量系统登录信息被systemd-journald进程存储于内存,造成内存占用过高。在日常运维中,若无需保留相关日志,建议优化systemd-journald配置,避免不必要的内存消耗。

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