1. Opened the website backend URL, and received an error: Unable to connect to database: Can’t connect to local MySQL server through socket ‘/var/lib/mysql/mysql.sock’ (2)
2. To fix the MySQL connection error, I checked the configuration file of the ISC framework (Interspire Shopping Cart, a legacy e-commerce system) and confirmed that it connects to the local database. See Figure 1.
3. I then checked the MySQL status (to confirm whether it started successfully) and found that it had stopped. Starting MySQL failed.
[root@li1269-60 jfc]# service mysqld status |
mysqld is stopped
[root@li1269-60 jfc]# service mysqld start
Timeout error occurred trying to start MySQL Daemon.
Starting mysqld: [FAILED]
[root@li1269-60 jfc]#
4. I reviewed the key logs for the MySQL startup failure (the most critical troubleshooting command). Based on the MySQL log snippet provided, the core error is that Table ‘./jammerfromchina/cart_prodd’ is corrupted — this is the root cause of the MySQL startup timeout / failure (a corrupted table prevents the InnoDB/MyISAM engine from loading, causing the MySQL startup process to hang).
[root@li1269-60 jfc]# grep -i "error|fail|timeout" /var/log/mysqld.log
130419 7:01:24 [ERROR] /usr/libexec/mysqld: Table './jammerfromchina/cart_prodd
130419 7:01:24 [ERROR] /usr/libexec/mysqld: Table './jammerfromchina/cart_prodd
130419 7:01:24 [ERROR] /usr/libexec/mysqld: Table './jammerfromchina/cart_prodd
130419 7:01:24 [ERROR] /usr/libexec/mysqld: Table './jammerfromchina/cart_prodd
130419 7:01:24 [ERROR] /usr/libexec/mysqld: Table './jammerfromchina/cart_prodd
130419 7:01:24 [ERROR] /usr/libexec/mysqld: Table './jammerfromchina/cart_prodd
130419 7:01:24 [ERROR] /usr/libexec/mysqld: Table './jammerfromchina/cart_prodd
130419 7:01:24 [ERROR] /usr/libexec/mysqld: Table './jammerfromchina/cart_prodd
130419 7:01:24 [ERROR] /usr/libexec/mysqld: Table './jammerfromchina/cart_prodd
130419 7:01:24 [ERROR] /usr/libexec/mysqld: Table './jammerfromchina/cart_prodd
130419 7:01:24 [ERROR] /usr/libexec/mysqld: Table './jammerfromchina/cart_prodd
130419 7:01:24 [ERROR] /usr/libexec/mysqld: Table './jammerfromchina/cart_prodd
130419 7:01:24 [ERROR] /usr/libexec/mysqld: Table './jammerfromchina/cart_prodd
130419 7:01:24 [ERROR] /usr/libexec/mysqld: Table './jammerfromchina/cart_prodd
130419 7:01:24 [ERROR] /usr/libexec/mysqld: Table './jammerfromchina/cart_prodd
130419 7:01:24 [ERROR] /usr/libexec/mysqld: Table './jammerfromchina/cart_prodd
130419 7:01:24 [ERROR] /usr/libexec/mysqld: Table './jammerfromchina/cart_prodd
130419 7:01:24 [ERROR] /usr/libexec/mysqld: Table './jammerfromchina/cart_prodd
130419 7:01:24 [ERROR] /usr/libexec/mysqld: Table './jammerfromchina/cart_prodd
130419 7:01:24 [ERROR] /usr/libexec/mysqld: Table './jammerfromchina/cart_prodd
130419 7:01:24 [ERROR] /usr/libexec/mysqld: Table './jammerfromchina/cart_prodd
130419 7:01:24 [ERROR] /usr/libexec/mysqld: Table './jammerfromc^C[ 3502.924666
5. Confirming whether disk resources are sufficient is a critical prerequisite for troubleshooting the current issue (a full disk is one of the core causes of MySQL startup failures and table corruption). Final confirmation: the disk is 100% full (the root partition /dev/sda has exhausted its 78G). See Figure 2.
[root@li1269-60 jfc]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda 78G 78G 0 100% /
tmpfs 1.9G 116K 1.9G 1% /dev/shm
6. I noticed that the Linode instance could now be resized. The current Linode plan has 4 GB of RAM and 80 GB of storage. It can be resized to a Linode plan with 8 GB of RAM and 160 GB of storage. Reference: Troubleshooting analysis of a failed Linode instance configuration upgrade, upgrading the configuration to 160GB.
7. I checked the disk usage again and confirmed it met expectations.
[root@li1269-60 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda 148G 78G 68G 54% /
tmpfs 3.9G 116K 3.9G 1% /dev/shm
[root@li1269-60 ~]#
8. Now, upon opening the backend, there are no more errors. I can log in normally. See Figure 3.
