Managing write access to data storage devices for spontaneous de-staging of cache

A data storage system comprising:

• a plurality of physical storage devices;
• a cache for temporarily storing data corresponding to the plurality of physical storage devices;
• one or more processors;
• and
• a memory comprising code stored thereon that, when executed, performs a method comprising:
• determining a cumulative amount of storage space that is required to be available on the plurality of physical storage devices to adequately support a spontaneous de-staging of data in the cache to at least one of the plurality of physical storage devices if power fails on the storage system;
• estimating an amount of time available to spontaneously de-stage the cache;
• determining a number of physical storage devices necessary to de-stage the cache based on the estimated amount of time available;
• selecting, based on the determined number of physical storage devices necessary to de-stage the cache, two or more of the plurality of physical storage devices to receive de-staged data from the cache in case of a spontaneous de-staging of the cache;
• for the two or more of the plurality of physical storage devices, determining an apportioned amount of the cumulative amount for the respective physical storage device to have available for storing data in case of a spontaneous de-staging of the cache;
• for each of the two or more physical storage devices, controlling a first threshold amount of storage space to be consumed on the physical storage space before I/O writes targeting the physical storage device are blocked, the first threshold amount based at least in part on the respective determined apportioned amount for the physical device;
• and
• for a first of the two or more physical storage devices, blocking writes targeting the first physical storage device if it is determined that the first threshold amount of storage space has been consumed on the first physical storage device.

One or more non-transitory computer-readable media having software stored thereon for a storage system including a plurality of physical storage devices and a cache for temporarily storing data corresponding to the plurality of physical storage devices, the software comprising:

• executable code that determines a cumulative amount of storage space that is required to be available on the plurality of physical storage devices to adequately support a spontaneous de-staging of data in the cache to at least one of the plurality of physical storage devices if power fails on the storage system;
• executable code that estimates an amount of time available to spontaneously de-stage the cache;
• executable code that determines a number of physical storage devices necessary to de-stage the cache based on the estimated amount of time available;
• executable code that selects, based on the determined number of physical storage devices necessary to de-stage the cache, two or more of the plurality of physical storage devices to receive de-staged data from the cache in case of a spontaneous de-staging of the cache;
• executable code that, for the two or more of the plurality of physical storage devices, determines an apportioned amount of the cumulative amount for the respective physical storage device to have available for storing data in case of a spontaneous de-staging of the cache;
• executable code that, for each of the two or more physical storage devices, controls a threshold amount of storage space to be consumed on the physical storage space before I/O writes targeting the physical storage device are blocked, the first threshold amount based at least in part on the respective determined apportioned amount for the physical device;
• and
• executable code that, for a first of the two or more physical storage devices, blocks writes targeting the first physical storage device if it is determined that the first threshold amount of storage space has been consumed on the first physical storage device.