I have a Ubuntu 11.4 system with a software implementation of RAID5 using 5 - 1T SATA disks. It was setup using mdadm and works as it should. However, when the disk array is mounted, and without any other I/O to the array, a continual periodic access is occurring in about a one second interval. I've tried several monitoring programs and are unable to find a process that is accessing the array periodically. It doesn't seem to affect the array's performance but is annoying. Does anyone know what process might be and how to stop it or is it a required process to support the RAID5?