Hewlett Packard Enterprise Development LP

Mandar Samant

Gurunatha Karaje

Sourabh Yerfule

Sagar Trehan

Vanco Buca

Zhaosheng Zhu

Methods, systems, and programs are presented for controlling the flow of data into a device in the presence of writes that are unaligned along boundaries associated with a block size. One method includes operations for identifying admission data rates for volumes, and for tracking a utilization rate of a memory that stores data of incoming writes. The method determines if incoming writes include unaligned data. When the memory utilization rate is above a first threshold, a first flow control is applied that includes a reduction of admission rates of volumes having unaligned writes while maintaining admission rates of volumes without unaligned writes. When the utilization rate is above a second threshold that is greater than the first threshold, a second flow control is applied in addition to the first flow control. The second flow control includes a reduction of a system admission rate for all incoming writes.

Flow control for unaligned writes in network storage device

Methods for scheduling operations in a scheduler hierarchy of a storage system. One method includes scheduling a first IO having a first cost at a first flow scheduler of a first flow configured to schedule IOs accessing a volume as executed on a first core processor. A global cost is updated with the first cost, wherein the global cost is shared by a plurality of flows of a plurality of core processors. An intervening cost is determined of at least one IO possibly scheduled before the first set of IOs by one or more flow schedulers of one or more flows configured to schedule IOs accessing the volume as executed on the plurality of core processors. A current cost is updated based on the first cost and the intervening cost. IOs and MBPS limits are set independently for the volume, each controlling scheduling through a corresponding accumulating current cost.

Methods to apply IOPS and MBPS limits independently using cross charging and global cost synchronization

Methods and systems are presented for allocating resources based on dynamic weight accumulation performed in a bottom-up fashion in a scheduler hierarchy of a storage system. One method includes assigning weights to leaf schedulers at a bottom level of schedulers in a scheduler hierarchy comprising a plurality of levels of schedulers. Between two levels, each parent scheduler is associated with a unique plurality of children schedulers. For each leaf scheduler that is active, the method includes propagating a corresponding weight of a corresponding leaf scheduler to every higher level in the scheduler hierarchy, such that a corresponding scheduler at a corresponding level is associated with an accumulation of weights of its descendent schedulers. The method includes distributing resources assigned to the scheduler hierarchy based on accumulated weights at each level, such that the corresponding scheduler is proportioned resources based on the accumulation of weights of its descendent schedulers.

Dynamic weight accumulation for fair allocation of resources in a scheduler hierarchy

Examples include acquisition of IOPS limits and MBPS limits independently at a parent scheduler in a scheduler hierarchy of a storage system, wherein the scheduler hierarchy includes a parent level and a child level below the parent level. Examples include setting IOPS limits and MBPS limits independently at each child scheduler placed within the child level of the scheduler hierarchy. Examples include receiving a CPU resource allocation at the parent scheduler, wherein the CPU resource allocation is convertible to an IOPS allocation at the parent scheduler. Example include distributing the IOPS allocation among the child schedulers below the parent scheduler such that each of the child schedulers receive the same distribution of the IOPS allocation. Example include allocating IOPS between the child schedulers based on their corresponding IOPS limits.

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Mandar Samant