On some CentOS VMs running on VMWare I was seeing the following errors in the syslog:
Jul 19 09:35:08 hostname kernel: hdc: drive_cmd: status=0x51 { DriveReady SeekComplete Error }
Jul 19 09:35:08 hostname kernel: hdc: drive_cmd: error=0x04 { AbortedCommand }
Jul 19 09:35:08 hostname kernel: ide: failed opcode was: 0xec
Looks like while installing munin-node a plugin was configured to check the SMART hard disk temperature and this check was failing so to stop the error messages
rm /etc/munin/plugins/hddtemp_smartctl
/etc/init.d/munin-node restart
Oh man! You saved my life! I was looking for explanation of this error for a few good hours and everything was just not working or not making any sense. This was it! Thanks for sharing 🙂