disk full on Centos
Find big files and remove them if possible:
find / -mount -size +8096 -lsfind / -mount -name core -lsdu -sh /* (and repeat for subsequent dirs on /)
Probably something is flooding your / or you have to many old kernels. Cleaning up will help, your / should be big enough because you've a seperated /var and /usr (and /data ...).