The MySQL database backup can be taken using mysqldump command from command line in a Linux server.
Sometimes, the following error may occur while taking database backup
"'Got error 28 from storage engine' when trying to dump tablespaces"
Though the error does not provide much information, the issue is related with the disk space on the server.
In this case
1) Login into the server as root user from command prompt.
2) Check the disk usage.
# df -h
3) Even though more than 20% disk space is available, delete some files.
4) Check by taking the database backup again.
In my case even though more than 18% disk space was free, the error occurred. On removing some files, the error was gone.
Hope this helps!