The 9750 controller includes a number of fault tolerance features to address multiple error conditions.  The controller must react to protect the data while also working to avoid unnecessary degradation of the units for transient but correctable errors.

If a drive is removed while unwritten data exists in the drive based write cache, the immediate actions of the system administrator could lead to the unrecoverable loss of that cache data.  When a drive is pulled with active I/O running, wait at least 10 seconds before reinserting the drive.  This provides enough reaction time for the controller to handle the threatened data and ultimately store it safely for further use.  Reinsertion of the drive before the system conditions can be fully assessed by the controller can compromise the best possible outcome for the fault tolerance routines.