HP StorageWorks 1000 Modular Smart Array - Manual (Page 23)

MSA1000 Controller
23 MSA1000 Controller User Guide
Recovery ROM and ROM Cloning
Recovery ROM
Each MSA1000 Controller contains ROM (Read-Only Memory), which holds the
firmware that operates the controller. The Recovery ROM feature stores two
complete firmware images in the ROM: one active image and one backup image.
When the controller is powering up, it checks both firmware images to ensure
they are valid. If either one is not, the valid image will be copied on top of the
invalid image to correct it. This is referred to as auto-flashing. All of this
functionality is done automatically by the controller and does not require any user
intervention.
ROM Cloning
Note: For an MSA1000 to operate in a redundant controller configuration, it must
contain two controllers that are executing the same version of firmware. During power
up (or if an optional controller is hot-plugged while the MSA1000 is already
operating) the firmware versions on both controllers are compared. If they are not the
same, then the ROM Cloning feature will attempt to copy one version of firmware onto
the other controller. After the copy has been completed, the controller that was modified
will be automatically reset. Once the reset controller has powered up the two controllers
should then start redundant operation. All of this functionality is done automatically by
the controllers and does not require any user intervention.
The determination as to which firmware version will be used is based on the
following criteria:
■ If the MSA1000 is being powered up with both controllers inserted, then the
most recent version of firmware will be used regardless of which controller it
resides.
■ If the MSA1000 is already operating and an optional controller is
hot-plugged, then the version of firmware that is on the original
(non-hot-plugged) controller will be used regardless of its version. This
ensures that any host initiated I/O to the controller is not interrupted.
There is the possibility that a specific version of firmware may not be compatible
with certain hardware revisions of a controller. In this scenario, the most recent
firmware version that is compatible with both controllers will be copied to the
controller with the incompatible firmware version. However, if the controller that