Flow control for unaligned writes in network storage device

A network storage device comprising:

• a processor;
• a plurality of storage devices;
• a non-volatile random access memory (NVRAM) for storing data of incoming writes to the volumes;
• and
• a non-transitory computer-readable storage medium comprising instructions executable by the processor to:
• determine a respective utilization rate of the NVRAM at each of a plurality of times, wherein determination of the utilization rate of the NVRAM comprises dividing an amount of currently-used space of the NVRAM by a total size of the NVRAM;
• in response to a determination that the utilization rate of the NVRAM at a first time of the plurality of times is above a first utilization threshold, apply a first flow control at the network storage device, the first flow control including a reduction, to a non-zero amount, of admission data rates for incoming writes from each volume of the network storage device having an amount of unaligned writes exceeding an unaligned threshold while maintaining admission data rates for incoming writes from each volume of the network storage device having an amount of unaligned writes that does not exceed the unaligned threshold, wherein an unaligned write has at least one of a starting address or an ending address that is not a multiple of a block size defined for the respective volume;
• and
• in response to a determination that the utilization rate of the NVRAM at a second time of the plurality of times is above a second utilization threshold that is greater than the first threshold, apply a second flow control at the network storage device, the second flow control including a reduction of a system admission data rate for all incoming writes from all of the volumes of the network storage device.

A non-transitory computer-readable storage medium storing machine readable instructions for controlling a flow of data into a storage device, the instructions, executable by a processor to:

• identify admission data rates for volumes in the storage device;
• determine a respective utilization rate of an incoming write memory in the storage device at each of a plurality of times, wherein the incoming write memory is to store data of incoming writes to the volumes, wherein the utilization rate is determined by dividing an amount of currently-used space of the incoming write memory by a total size of the incoming write memory;
• in response to a determination that the utilization rate of the incoming write memory at a first time is above a first utilization threshold, apply a first flow control at the storage device, the first flow control to reduce, to a non-zero amount, admission data rates for incoming writes from each volume of the storage device having an amount of unaligned writes exceeding an unaligned threshold while maintaining admission data rates for incoming writes from each volume of the storage device having an amount of unaligned writes that does not exceed the unaligned threshold, wherein an unaligned write has at least one of a starting address or an ending address that is not a multiple of a block size defined for the respective volume;
• and
• in response to a determination that the utilization rate of the incoming write memory at a second time is above a second utilization threshold that is greater than the first utilization threshold, apply a second flow control at the storage device, the second flow control to reduce the admission data rates for incoming writes from each volume of the storage device, including each volume having an amount of unaligned writes exceeding the unaligned threshold and each volume having an amount of unaligned writes not exceeding the unaligned threshold.