调整最大TCP连接数：

sysctl -w net.ipv4.ip_local_port_range="1024 65535"
sysctl -w net.core.somaxconn="1024"
sysctl -w net.ipv4.tcp_max_syn_backlog="65535"

启用TCP连接的时间等待 (TCP TIME-WAIT) 状态减少：

sysctl -w net.ipv4.tcp_tw_reuse="1"
sysctl -w net.ipv4.tcp_tw_recycle="1"

Raspberry Pi Zero W吃灰有一段时间了，想着能否废物利用，使用普通USB摄像头改成一个RTSP协议网络摄像头。

1. 查看摄像头是否可用

查看是否已识别USB摄像头：

lsusb -t

安装luvcview：

sudo apt-get install luvcview

在升级GitLab后，进行gitlab-ctl reconfigure的时候，碰到问题：

bash[migrate gitlab-rails database] (gitlab::database_migrations line 55) had an error: Mixlib::ShellOut::ShellCommandFailed: Expected process to exit with [0], but received '1'

Problem

I got the whole thing up and running in debug. But when I went for our dotnet run, I got the following crash:

The type initializer for 'Gdip' threw an exception.

公司需要注册几个小程序，注册小程序需要邮箱，腾讯企业邮箱新账户需要绑定手机号和个人微信，不适合批量使用。昨天用turbomail搭建了邮件服务，功能很强大，但仅限于windows。因某些原因，服务器操作系统今天上午更改为Linux，所以需要重新搭建一套邮件服务。

1、查看已挂载的磁盘以及挂载到的目录

df -h

上图中 最大的 860G 硬盘挂载到了 www 这个目录，那我们来将 这个磁盘改变挂载到 /home

How do I configure Apache HTTPD to listen on multiple ports under RHEL / Fedora / CentOS Linux Server?

Multiple ports can be configured via Listen directive under Apache web server. By default httpd listens on TCP port 80.

How to configure httpd to listen multiple ports? Open configure file /etc/httpd/conf/httpd.conf and modify the Listen directive tells the server to accept incoming requests on the specified port. Multiple Listen directives may be used to specify a number of ports to listen to.

0. GPS模块

因为GPS模块仅做测试，不用于生产环境，我选了一块便宜的GT-U8模块。使用USB串口模块接好GPS模块后，收到GPS上报数据。

基本设置

• 国家一定要选择China，否则可能会造成SSH频繁断开和严重的卡顿！
• 语言选择English，方便根据报错查找问题。

开启WIFI

连接WiFi网络

进入桌面找到并连接WiFi。如果频繁断开或者无法连接，运行：

sudo systemctl restart dhcpcd.service
sudo systemctl restart networking.service
sudo reboot

Boutique: CentOS7 and FastDFS build image server

brief introduction

FastDFS is an open source high-performance Distributed File System. It manages files. Its main functions include: file storage, file synchronization, file access (file upload, file download), etc. It mainly solves the problem of massive data storage, especially for small and medium-sized files (recommended range: 4KB < file)_ Size < 500MB).

FastDFS system has three roles: tracker server, storage server and client.