File system errors can manifest in many ways. Occasionally when executing a command, either manually or via a function in the cPanel interface, errors will be returned that indicate read or write operations cannot be completed. The following is a good example:
# whmapi1 listaccts
reason: "API failure: (XID r57fjf) The system failed to read the directory “GLOB(0x2fb0788)” because of an error: Input/output error"
Other key phrases include
Read-only file system,
reading directory block,
When a file system error occurs, it becomes impossible to reliably read or write data to and from the partition with errors. File system errors may occur due to physical defects with the disk or due to corruption of the file system.
Most modern cPanel servers use EXT4 or XFS file systems. One way to gather more information about potential file system errors and verify they exist is by reviewing the system log
/var/log/messages or the systemd journal. For example:
grep -i xfs /var/log/messages
journalctl -xe | grep -i xfs
grep 'EXT4-fs error' /var/log/messages
You may also want to view a health report for the affected disk using
smartctl -a /dev/sdb
Fixing file system errors usually requires a file system check (fsck). Depending on which drive is affected, as well as the type of server you use (e.g. bare metal versus virtualized), and whether or not you have physical access to your server, the steps required to solve this type of issue vary widely.
If you have determined your server has file system errors, we recommend you contact your system administrator, data center technician, or hosting provider.