Problem:
Upgraded MySQL 5.1 to MySQL 5.6. After the upgrade, it failed to start MySQL.
Solution:
Open the MySQL log file and enter the command:
vim /var/log/mysqld.log
Find the error message in the log file. The error here is that the ibdata1 file size parameter has been modified, causing it to be different from the default value.
(Recommended tutorial: centos usage tutorial)
Solution:
Open the MySQL configuration file, Enter the command:
vim /etc/my.cnf
As stated in the error message: the value of ibdata1 is 640 pages and the value in the configuration file is 768 pages. So just modify the value of ibdata1 in innodb_data_file_path in my.cnf.
First calculate the initial value of ibdata1: 640/64 = 10M
The final configuration is:
innodb_data_file_path = ibdata1:10M:autoextend
If my.cnf does not have this configuration, just add it.
Related video tutorial recommendations: linux video tutorial
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CentOS is an open source distribution based on RedHatEnterpriseLinux, focusing on stability and long-term support, suitable for a variety of server environments. 1. The design philosophy of CentOS is stable and suitable for web, database and application servers. 2. Use YUM as the package manager to release security updates regularly. 3. Simple installation, you can build a web server with a few commands. 4. Advanced features include enhanced security using SELinux. 5. Frequently asked questions such as network configuration and software dependencies can be debugged through nmcli and yumdeplist commands. 6. Performance optimization suggestions include tuning kernel parameters and using a lightweight web server.

CentOS is widely used in server management and web hosting. Specific methods include: 1) using yum and systemctl to manage the server, 2) install and configure Nginx for web hosting, 3) use top and mpstat to optimize performance, 4) correctly configure the firewall and manage disk space to avoid common problems.

CentOS is a stable, enterprise-grade Linux distribution suitable for server and enterprise environments. 1) It is based on RedHatEnterpriseLinux and provides a free, open source and compatible operating system. 2) CentOS uses the Yum package management system to simplify software installation and updates. 3) Support advanced automation management, such as using Ansible. 4) Common errors include package dependency and service startup issues, which can be solved through log files. 5) Performance optimization suggestions include the use of lightweight software, regular cleaning of the system and optimization of kernel parameters.

Alternatives to CentOS include RockyLinux, AlmaLinux, OracleLinux, and SLES. 1) RockyLinux and AlmaLinux provide RHEL-compatible binary packages and long-term support. 2) OracleLinux provides enterprise-level support and Ksplice technology. 3) SLES provides long-term support and stability, but commercial licensing may increase costs.

Alternatives to CentOS include UbuntuServer, Debian, Fedora, RockyLinux, and AlmaLinux. 1) UbuntuServer is suitable for basic operations, such as updating software packages and configuring the network. 2) Debian is suitable for advanced usage, such as using LXC to manage containers. 3) RockyLinux can optimize performance by adjusting kernel parameters.

The CentOS shutdown command is shutdown, and the syntax is shutdown [Options] Time [Information]. Options include: -h Stop the system immediately; -P Turn off the power after shutdown; -r restart; -t Waiting time. Times can be specified as immediate (now), minutes ( minutes), or a specific time (hh:mm). Added information can be displayed in system messages.

The key differences between CentOS and Ubuntu are: origin (CentOS originates from Red Hat, for enterprises; Ubuntu originates from Debian, for individuals), package management (CentOS uses yum, focusing on stability; Ubuntu uses apt, for high update frequency), support cycle (CentOS provides 10 years of support, Ubuntu provides 5 years of LTS support), community support (CentOS focuses on stability, Ubuntu provides a wide range of tutorials and documents), uses (CentOS is biased towards servers, Ubuntu is suitable for servers and desktops), other differences include installation simplicity (CentOS is thin)

Steps to configure IP address in CentOS: View the current network configuration: ip addr Edit the network configuration file: sudo vi /etc/sysconfig/network-scripts/ifcfg-eth0 Change IP address: Edit IPADDR= Line changes the subnet mask and gateway (optional): Edit NETMASK= and GATEWAY= Lines Restart the network service: sudo systemctl restart network verification IP address: ip addr


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