Patent ID: 11861340
Assignee: NETAPP, INC.
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 6:
7. A system comprising:
one or more processing resources; and
a non-transitory computer-readable medium, coupled to the one or more processing resources, having stored therein instructions that when executed by the one or more processing resources cause the one or more processing resources to:
implement a multi-tiered file system in a storage node, the multi-tiered filesystem having an on-disk layout that segregates a base configuration of an operating system of the storage node from runtime data associated with the operating system, containing modifications to the base configuration, the multi-tiered file system comprising (i) a read-only layer that contains the base configuration for the storage node including an image of a first version of the operating system and (ii) a read-write layer that contains the runtime data;
upgrade the first version of the operating system to a second version of the operating system without requiring a root partition of a boot disk of the storage node to be recreated by:
combining the read-only layer and the read-write layer into an overlay filesystem that is presented to the operating system as the root partition; and
configuring the storage node to use a new image of the second version of the operating system in place of the image stored on the root partition; and
performing a soft reboot to cause a return to factory image (RTFI) process to install the second version of the operating system via the overlay filesystem without modifying the read-write layer.