20 Linux server performance tuning tips you have to know

                  Linux is an open source operating system that supports various hardware platforms. Linux servers are well known around the world. The main difference between Windows and Windows is that Linux servers generally do not provide GUI (graphical user interface) by default, but the command line. The interface, its main purpose is to efficiently process non-interactive processes, response time is not so important, on the contrary, the ability to handle high loads for a long time is the most critical. The Linux High Availability Server Cluster solution allows IT system administrators to handle many common hardware and software failures, allowing multiple computers to work together, providing assurance that critical services are up and running, and that system administrators can perform maintenance and upgrades without disrupting service.

Linux servers have various uses, such as Web server or branch office internal servers, CMS or CRS servers, file servers (for Windows and /or Linux user services), VoIP phone servers, mail or domain name servers, database servers, clouds Calculate infrastructure nodes, etc. in the configuration.

Linux is rich, powerful, and flexible, and you can use it to accomplish a variety of tasks. In this article, we'll discuss some tips for improving the performance of Linux servers.

1, adjust the Linux kernel elevator algorithm for disk I /O

After selecting the file system, there are some kernel and mount options may affect its performance, one of the kernel settings It is an elevator algorithm that adjusts the elevator algorithm so that the system can balance low latency requirements and collect enough data to efficiently organize read and write requests to the disk.

2, disable unnecessary daemons, save memory and CPU resources

Each server runs many daemons or services, and ironically, there are many that are usually not Required, these services are not working, but they consume valuable memory and CPU time. In addition, they may put the server in a dangerous situation. Running one more service is equivalent to opening a long-opening door to the hacker. Therefore, you should remove them from the server. The biggest advantage of disabling them is to speed up the startup time and release. RAM. In addition, you can reduce the number of processes that the CPU needs to process. Another benefit of disabling them is to enhance server security, because fewer daemons mean fewer vulnerabilities that can be exploited and exploited.

The following are some Linux daemons that should be disabled. By default, they all run automatically:
No. Daemon Description 1 Apmd Advanced Power Management Daemon 2Nfslock for NFS file locking 3Isdn ISDN Moderm supports 4Autofs to automatically mount the file system in the background (such as auto-mount CD-ROM) 5Sendmail mail transfer agent 6Xfs X Window font server

3, turn off the GUI

Generally speaking, the Linux server is Without the GUI, all administrative tasks can be done from the command line, so it is best to turn off the GUI, redirect the X display or display it through a web browser interface. In order to disable the GUI, "init level" should be set to 3 (command line login) instead of 5 (graphic login), if you need a GUI, you can run startx to enter the graphical user interface at any time.

4. Clean up unwanted modules or functions

There are too many functions or modules that are started in the server package that are not actually needed (such as many functional modules in Apache) Check the Apache configuration file carefully to see if FrontPage support or other additional modules are really needed. If you don't need it, you should not hesitate to disable it from the server. This will help increase system memory availability and free up more. Resources give software that really needs them to run faster.

5. Disable Control Panel

In Linux, there are many popular control panels, such as Cpanel, Plesk, Webmin and phpMyAdmin. I believe that every Linux novice user likes these control panels. However, disabling these packages can free up about 120MB of memory, so I highly recommend disabling these control panels unless they really need to be used, they can be passed through a PHP script (although somewhat unsafe), or command line commands. Enabled, after doing so, memory usage can be reduced by approximately 30-40%.

6, improve Linux Exim server performance

There are many ways to improve the server's Exim performance, one of which is to use the DNS cache daemon, which can reduce the bandwidth and CPU required to resolve DNS records Time, DNS caching improves network performance by eliminating the need to look up DNS records from the root node every time. Djbdns is a very powerful DNS server with DNS caching. Djbdns is more secure and better than BIND DNS server. It can be downloaded directly from http://cr.yp.to/or from a package provided by Red Hat.

7, using AES256 to enhance gpg file encryption security

In order to improve the security of backup files or sensitive information, many Linux system administrators will use gpg for encryption, when using gpg, it is best to specify Gpg uses the AES256 encryption algorithm. AES256 uses a 256-bit key. It is an open encryption algorithm that is used by the National Security Agency (NSA) to protect top secret information. Nothing is safer than it.

8. Remote Backup Service Security

Security is the most important factor in choosing a remote backup service. Most system administrators are afraid of two things: (hacker) can delete backup files, not from Backup recovery system.

In order to ensure 100% security of the backup file, the backup service company provides a remote backup server, using spp script or RSYNC to transfer data through SSH, so that no one can directly access and access the remote system, so no one Data can be deleted from the backup service. When choosing a remote backup service provider, it's best to understand its service robustness in several ways, and if you can, you can test it yourself.

9, update the default kernel parameter settings

In order to successfully and successfully run enterprise applications, such as database servers, you may need to update some default kernel parameter settings, for example, 2.4.x series kernel messages The queue parameter msgmni has a default value (for example, shared memory, or shmmax has only 33535432 bytes by default on Red Hat systems), it only allows limited database concurrent connections. The following provides some recommended values ​​for the database server to run better ( From the IBM DB2 support site):

kernel.shmmax=268435456 (32-bit) kernel.shmmax=1073741824 (64-bit) kernel.msgmni=1024fs.file-max=8192kernel.sem=”250 32000 32 1024 "
10, Optimized TCP
Optimizing the TCP protocol helps to improve network throughput. The bandwidth used for communication across the WAN is larger. The longer the delay, the larger the TCP Linux size is recommended. To increase the data transfer rate, the TCP Linux size determines how much data the sending host can send to the receiving host when it does not receive a data transmission acknowledgement.