Usually it means that that the drive has failed. Maybe because of too much overclocking or hardware error. You never know.
But. You should try to run "nvidia-smi". Usually it will give you some useful info on which GPU is failing or some other reasons.Like
"GPU blah-blah is insufficiently powered"
"GPU blah-blah bus error"
"GPU blah-blah IO error or temp readings error"
Generally miner will try to say you something also. Like this
So try to reduce OC, look at /var/log/syslog to find some details, run "dmesg -f" to watch errors in realtime.