Flow control with a dynamic window in a storage system with latency guarantees

• US 10,048,874 B1
• Filed: 06/29/2016
• Issued: 08/14/2018
• Est. Priority Date: 06/29/2016
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Inventors: Shveidel, Vladimir, Shoikhet, Kirill
• Primary Examiner(s): Chappell, Daniel C
• Application Number:
  US15/196,447
• Time in Patent Office: 776 Days
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0656 Data buffering arrangements
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

Described embodiments may provide methods and systems for receiving one or more input/output (I/O) requests by a storage system having at least one storage cluster. The storage system performs each I/O request with dynamic flow control by determining a latency associated with the one or more received I/O requests during at least one monitoring interval and tracking I/O requests to the storage cluster. If a received I/O request exceeds a choker threshold value of the storage cluster, the I/O request is queued. Otherwise, the received I/O request is performed for the storage cluster.

Claims

1. A method comprising:

receiving one or more input/output (I/O) requests by a storage system having at least one storage cluster, each of the received I/O requests associated with a storage cluster;

performing the I/O request with dynamic flow control by;

determining a latency associated with the one or more received I/O requests during at least one monitoring interval;

tracking I/O requests to the storage cluster;

if a received I/O request exceeds a choker threshold value of the storage cluster, queuing the received I/O request, otherwise, performing the received I/O request,

wherein determining the latency associated with the one or more received I/O requests during at least one monitoring interval comprises;

determining an end-to-end latency of each of the one or more received I/O requests performed for the storage cluster during the monitoring interval; and

determining latency for the storage cluster as at least one of;

a peak latency for the storage cluster during the monitoring interval, and an average latency for the storage cluster during the monitoring interval; and

based upon the determined latency for the storage cluster, adjusting the choker threshold value associated with the storage cluster, wherein adjusting the choker threshold value comprises;

if the determined latency for the storage cluster is below a first latency threshold value, increasing the choker threshold value by a first step value; and

if the determined latency for the storage cluster is above a second latency threshold value, decreasing the choker threshold value by a second step value,

wherein the choker threshold value of the storage cluster comprises one of;

a maximum number of concurrent I/O requests that can be processed by the storage cluster, and a maximum amount of data that can be processed by the storage cluster.

2. The method of claim 1, wherein the first latency threshold value and the second latency threshold value comprise the same value.

3. The method of claim 2, wherein the second step value is larger than the first step value.

4. The method of claim 1, wherein queuing the received I/O request comprises:

adding the received I/O request to a queue corresponding to the storage cluster associated with the I/O request; and

rejecting any queued I/O requests that have reached a retention interval value associated with the storage cluster.

5. The method of claim 1, further comprising, based upon one or more operating conditions of the storage system, adjusting the retention interval value.

6. A system comprising:

a processor; and

memory storing computer program code that when executed on the processor causes the processor to execute an input/output (I/O) request received by a storage system having at least one storage cluster operable to perform the operations of;

performing the I/O request with dynamic flow control by;

determining a latency associated with the one or more received I/O requests during at least one monitoring interval;

tracking I/O requests to the storage cluster; and

if a received I/O request exceeds a choker threshold value of the storage cluster, queuing the received I/O request, otherwise, performing the received I/O request, wherein determining the latency associated with the one or more received I/O requests during at least one monitoring interval comprises;

determining an end-to-end latency of each of the one or more received I/O requests performed for the storage cluster during the monitoring interval; and

determining latency for the storage cluster as at least one of;

a peak latency for the storage cluster during the monitoring interval, and an average latency for the storage cluster during the monitoring interval; and

based upon the determined latency for the storage cluster, adjusting the choker threshold value associated with the storage cluster, wherein adjusting the choker threshold value comprises;

if the determined latency for the storage cluster is below a first latency threshold value, increasing the choker threshold value by a first step value; and

if the determined latency for the storage cluster is above a second latency threshold value, decreasing the choker threshold value by a second step value,

wherein the choker threshold value of the storage cluster comprises one of;

a maximum number of concurrent I/O requests that can be processed by the storage cluster, and a maximum amount of data that can be processed by the storage cluster.

7. The system of claim 6, wherein the first latency threshold value and the second latency threshold value comprise the same value.

8. The system of claim 6, wherein the second step value is larger than the first step value.

9. The system of claim 6, wherein the system is further operable to perform the operations of:

adding the received I/O request to a queue corresponding to the storage cluster;

rejecting any queued I/O requests that have reached a retention interval value associated with the storage cluster; and

based upon one or more operating conditions of the storage system, adjusting the retention interval value.

10. A computer program product including a non-transitory computer readable storage medium having computer program code encoded thereon that when executed on a processor of a computer causes the computer to execute an input/output (I/O) request received by a storage system having at least one storage cluster, the computer program product comprising:

computer program code for receiving one or more input/output (I/O) requests; and

computer program code for performing the I/O request with dynamic flow control by;

determining a latency associated with the one or more received I/O requests during at least one monitoring interval;

tracking I/O requests to the storage cluster; and

if a received I/O request exceeds a choker threshold value of the storage cluster, queuing the received I/O request, otherwise, performing the received I/O request, wherein determining the latency associated with the one or more received I/O requests during at least one monitoring interval comprises;

determining an end-to-end latency of each of the one or more received I/O requests performed for the storage cluster during the monitoring interval; and

determining latency for the storage cluster as at least one of;

a peak latency for the storage cluster during the monitoring interval, and an average latency for the storage cluster during the monitoring interval; and

based upon the determined latency for the storage cluster, adjusting the choker threshold value associated with the storage cluster, wherein adjusting the choker threshold value comprises;

if the determined latency for the storage cluster is below a first latency threshold value, increasing the choker threshold value by a first step value; and

if the determined latency for the storage cluster is above a second latency threshold value, decreasing the choker threshold value by a second step value,

wherein the choker threshold value of a storage cluster comprises one of;

a maximum number of concurrent I/O requests that can be processed by the storage cluster, and a maximum amount of data that can be processed by the storage cluster.

11. The computer program product of claim 10, further comprising:

computer program code for adding the received I/O request to a queue corresponding to the storage cluster;

computer program code for rejecting any queued I/O requests that have reached a retention interval value associated with the storage cluster; and

computer program code for adjusting the retention interval value based upon one or more operating conditions of the storage system.