When there is disk I/O problem, mysql or gateway would not be able to run properly.
fsck command should be helpful, but it requires the file system is un-mounted.
There is another way to run fsck on all file systems at boot time. This article is for those don't want to run fsck on all file systems, but just umount a mount point, and run fsck on it.
Here is an example to umount /tmp and run fsck on it.
Before proceed, ensure it's not a problem of file permission, or disk space running out.
1. shutdown all running processes
service ssg stop
service mysql stop
ps -ef|grep java
kill all the running applications
2. unmount /tmp
umount -l /tmp
3. run fsck on /tmp
4. Mount /tmp again.