Dynamic Instantiation and Management of Virtual Caching Appliances

• US 20130166724A1
• Filed: 12/22/2011
• Published: 06/27/2013
• Est. Priority Date: 12/22/2011
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: Network Appliance Incorporated (NetApp, Inc.)
• Inventors: Bairavasundaram, Lakshmi Narayanan, Soundararajan, Gokul, Mathur, Vipul, Voruganti, Kaladhar
• Granted Patent: US 9,274,838 B2
• Time in Patent Office: Days
• US Class Current: 709/224
• CPC Class Codes: G06F 11/3409 for performance assessment
• CPC Class Codes: G06F 12/0806 Multiuser, multiprocessor or multiprocessing cache systems
• CPC Class Codes: G06F 16/172 Caching, prefetching or hoarding of files
• CPC Class Codes: G06F 2009/4557 Distribution of virtual machine instances; Migration and load balancing
• CPC Class Codes: G06F 2009/45583 Memory management, e.g. access or allocation
• CPC Class Codes: G06F 2009/45595 Network integration; Enabling network access in virtual machine instances
• CPC Class Codes: G06F 9/5016 the resource being the memory
• CPC Class Codes: G06F 9/5077 Logical partitioning of resources; Management or configuration of virtualized resources specific details on emulation or internal functioning of virtual machines G06F9/455
• CPC Class Codes: H04L 41/0816 the condition being an adaptation, e.g. in response to network events
• CPC Class Codes: H04L 41/0823 characterised by the purposes of a change of settings, e.g. optimising configuration for enhancing reliability for optimising operational conditions of wireless networks H04W24/02
• CPC Class Codes: H04L 41/5041 characterised by the time relationship between creation and deployment of a service
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A service level objective (SLO) violation is detected for a workload of a networked storage system, based on a performance metric not being satisfied for the workload. In response to detecting the SLO violation, a controller determines that changing a level of caching at a node of the networked storage system will improve the performance metric for the workload. The controller implements the change by adjusting an operation of a virtual cache appliance (VCA) of the networked storage system. The adjusting can be instantiating a new VCA, or adjusting the level of caching at an existing VCA. The adjusting can be for caching related to the workload itself, or it can be caching for an intertering workload.

Claims

1. A method in a networked storage system comprising:

detecting, by a processing component of a first server device of the networked storage system, that utilization of memory resources allocated to cache data for workloads of the networked storage system is outside a target utilization, wherein the networked storage system includes at least one compute server coupled to a storage server and multiple workloads each associated with a compute server, based on at least one performance metric for access to the storage server for one or more workloads;

determining, by a processing component of a second server device of the networked storage system, that changing a level of caching at a selected one of the compute servers will cause improvement in the utilization of memory resources in the networked storage system; and

accessing a hypervisor of the selected compute server to modify the level of caching by dynamically adjusting resource allocation for a virtual cache appliance at the selected compute server.

2. The method of claim 1, wherein the first and second server devices are the same server device.

3. The method of claim 1, wherein the first server device is the storage server, and the second server device is a compute server of the networked storage system.

4. The method of claim 1, wherein the performance metric comprises a value of input/output per second IOPS).

5. The method of claim 1, wherein the performance metric comprises access latency.

6. The method of claim 1, wherein detecting that utilization is outside a target utilization comprises detecting a service level objective (SLO) violation for a workload, wherein the SLO violation indicates that a predefined performance metric is not satisfied for the workload;

and

wherein modifying the level of caching comprises dynamically adjusting operation of the virtual cache appliance to increase caching at the selected compute server.

7. The method of claim 6, wherein determining that changing a level of caching will cause improvement comprises:

determining to change an amount of caching at a caching level of the selected compute server.

8. The method of claim 6, wherein determining that changing a level of caching will cause improvement comprises:

determining to instantiate a virtual caching appliance (VCA) at the selected compute server.

9. The method of claim 8, further comprising:

reading frequently accessed memory items; and

warming up the instantiated VCA with the frequently accessed blocks.

10. The method of claim 6, wherein determining that changing a level of caching at the selected compute server will cause improvement comprises determining that changing a level of caching at a compute server associated with the workload for which the SLO violation is detected will cause improvement in the performance metric for the workload.

11. The method of claim 6, wherein the workload is a first workload, and wherein the determining further comprises:

determining that there is interference between the first workload and second workload for storage blocks; and

determining that changing a level of caching at a compute server associated with the second workload will cause improvement in the performance metric for the first workload.

12. The method of claim 1, wherein detecting that utilization is outside a target utilization comprises detecting underutilization of memory resources allocated to cache data for workloads of the networked storage system;

and

wherein modifying the level of caching comprises reducing the amount of resources allocated for a virtual cache appliance for caching.

13. The method of claim 12, wherein reducing the amount of resources allocated comprises removing a virtual cache appliance instance (VCA).

14. The method of claim 13, wherein removing the VCA further comprises:

identifying a group of at least one virtual cache appliance as candidates for removal;

calculating an impact on the performance metric of a workload serviced by the VCA; and

removing the VCA when the impact on the performance metric is within a threshold.

15. The method of claim 13, further comprising

rerouting a workload from the removed VCA to another VCA. in the networked storage system.

16. A networked storage system comprising:

a storage server;

multiple compute servers coupled to the storage server and multiple workloads each associated with a compute server;

a performance monitor to monitor utilization of memory resource allocated to cache data for workloads of the networked storage system; and

an analysis module coupled to the performance monitor to detect that utilization of memory resources allocated to cache data for workloads of the networked storage system is outside a target utilization based on at least one performance metric for access to the storage server for one or more workloads, determine that changing a level of caching at a selected one of the compute servers will cause improvement in the utilization of memory resources, and access a hypervisor of the selected compute server to modify the level of caching by dynamically adjusting resource allocation for a virtual cache appliance at the selected compute server.

17. The storage system of claim 16, wherein the performance monitor and the analysis module are executed on the same server in the storage system.

18. The storage system claim 16, wherein the performance monitor is an SLO monitor and is to detect a service level objective (SLO) violation for a workload, wherein the SLO violation indicates that a predefined performance metric is not satisfied for the workload;

and

wherein the analysis module is to access the hypervisor to modify the level of caching including dynamically adjusting operation of the virtual cache appliance to increase caching at the selected compute server.

19. The storage system of claim 18, wherein the analysis module is to determine to either change an amount of caching at a caching level of the selected compute server or instantiate a virtual caching appliance (VCA) at the selected compute server.

20. The storage system of claim 18, wherein instantiating the VCA further comprises:

the SLO monitor to read frequently accessed memory items; and

the analysis module to warm up the instantiated VCA with the frequently accessed blocks.

21. The storage system of claim 18, wherein the workload is a first workload, and wherein the analysis module is to further determine that there is interference between the first workload and second workload for storage blocks;

and determine that changing a level of caching at a compute server associated with the second workload will cause improvement in the performance metric for the first workload.

22. The storage system of claim 16, wherein the performance monitor is to detect underutilization of memory resources allocated to cache data for workloads of the networked storage system;

and

wherein the analysis module is to access the hypervisor to modify the level of caching including dynamically reducing the amount of resources allocated for a virtual cache appliance for caching.

23. The storage system of claim 22, wherein reducing the amount of resources allocated comprises removing a virtual cache appliance instance (VCA).

24. The storage system of claim 23, wherein to remove the VCA, the analysis module is to further

identify a group of at least one virtual cache appliance as candidates for removal;

calculate an impact on the performance metric of a workload serviced by the VCA; and

remove the VGA when the impact on the performance metric is within a threshold.

25. The storage system of claim 23, wherein the analysis module is to further

reroute a workload from the removed VCA to another VCA in the networked storage system.

26. An article of manufacture comprising a computer-readable storage medium having content stored thereon, which when accessed by a computing device causes the computing device to perform operations including:

detecting, by a processing component of a first server device of the networked storage system, that utilization of memory resources allocated to cache data for workloads of the networked storage system is outside a target utilization, wherein the networked storage system includes at least one compute server coupled to a storage server and multiple workloads each associated with a compute server, based on at least one performance metric for access to the storage server for one or more workloads;

determining, by a processing component of a second server device of the networked storage system, that changing a level of caching at a selected one of the compute servers will cause improvement in the utilization of memory resources in the networked storage system; and

accessing a hypervisor of the selected compute server to modify the level of caching by dynamically adjusting resource allocation for a virtual cache appliance at the selected compute server.

27. The article of manufacture of claim 26, wherein detecting that utilization is outside a target utilization comprises detecting a service level objective (SLO) violation for a workload, wherein the SLO violation indicates that a predefined performance metric is not satisfied for the workload;

and

wherein modifying the level of caching comprises dynamically adjusting operation of the virtual cache appliance to increase caching at the selected compute server.

28. The article of manufacture of claim 27, wherein determining that changing a level of caching will cause improvement comprises either:

determining to change an amount of caching at a caching level of the selected compute server;

or

determining to instantiate a virtual caching appliance (VCA) at the selected compute server.

29. The article of manufacture of claim 28, further comprising:

reading frequently accessed memory items; and

warming up the instantiated VCA with the frequently accessed blocks.

30. The article of manufacture of claim 27, wherein determining that changing a level of caching at the selected compute server will cause improvement comprises determining that changing a level of caching at a compute server associated with the workload for which the SLO violation is detected will cause improvement in the performance metric for the workload.

31. The article of manufacture of claim 26, wherein detecting that utilization is outside a target utilization comprises detecting underutilization of memory resources allocated to cache data for workloads of the networked storage system;

and

wherein modifying the level of caching comprises reducing the amount of resources allocated for a virtual cache appliance for caching.

32. The article of manufacture of claim 31, wherein reducing the amount of resources allocated comprises removing a virtual cache appliance instance (VCA).

33. The article of manufacture of claim 32, wherein removing the VCA further comprises:

identifying a group of at least one virtual cache appliance as candidates for removal;

calculating an impact on the performance metric of a workload serviced by the VCA; and

removing the VCA when the impact on the performance metric is within a threshold.

34. The article of manufacture of claim 32, further comprising

rerouting a workload from the removed VCA to another VCA in the networked storage system.