Updating of pinned storage in flash based on changes to flash-to-disk capacity ratio

A non-transitory computer-readable medium storing a computer program for upgrading a data storage system, the computer-readable medium comprising:

• program instructions for detecting a change in an amount of storage in a network storage device, the network storage device including disk storage and a solid state drive (SSD) cache, wherein pinned volumes in the network storage device are defined to have all active volume data cached in the SSD cache;
• program instructions for determining an updated flash capacity of the SSD cache;
• program instructions for determining an updated disk capacity of the disk storage;
• program instructions for determining an updated flash-to-disk ratio (FDR) as the updated flash capacity divided by the updated disk capacity;
• program instructions for determining an updated reserved space in SSD cache as a first function of the updated disk capacity, wherein an updated remaining space in SSD cache is based on the updated flash capacity and the updated reserved space;
• and
• program instructions for determining an updated pinnable space in SSD cache based on the updated disk capacity and the updated FDR

A network storage device comprising:

• disk storage;
• a solid state drive (SSD) cache, wherein pinned volumes in the network storage device are defined to have all active volume data cached in the SSD cache;
• and
• a processor operable to detect a change in an amount of storage in a network storage device, the network storage device including disk storage and a solid state drive (SSD) cache, wherein pinned volumes in the network storage device are defined to have all active volume data cached in the SSD cache;
• wherein the processor is operable to determine an updated flash capacity of the SSD cache;
• wherein the processor is operable to determine an updated disk capacity of the disk storage;
• wherein the processor is operable to determine an updated flash-to-disk ratio (FDR) as the updated flash capacity divided by the updated disk capacity;
• wherein the processor is operable to determine an updated reserved space in SSD cache as a first function of the updated disk capacity, wherein an updated remaining space in SSD cache is based on the updated flash capacity and the updated reserved space;
• and
• wherein the processor is operable to determine an updated pinnable space in SSD cache based on the updated disk capacity and the updated FDR.