VIRTUALIZATION SUPPORT FOR STORAGE DEVICES

• US 20140282514A1
• Filed: 03/14/2013
• Published: 09/18/2014
• Est. Priority Date: 03/14/2013
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: Fusion-IO Incorporated (Western Digital Corporation)
• Inventors: Talagala, Nisha, Brinicombe, Mark, Wipfel, Robert, Badam, Anirudh, Nellans, David, Carson, Neil
• Granted Patent: US 9,720,717 B2
• Time in Patent Office: Days
• US Class Current: 718/1
• CPC Class Codes: G06F 2009/45579 I/O management, e.g. providing access to device drivers or storage
• CPC Class Codes: G06F 9/45533 Hypervisors; Virtual machine monitors

Abstract

Techniques are disclosed relating to enabling virtual machines to access data on a physical recording medium. In one embodiment, a computing system provides a logical address space for a storage device to an allocation agent that is executable to allocate the logical address space to a plurality of virtual machines having access to the storage device. In such an embodiment, the logical address space is larger than a physical address space of the storage device. The computing system may then process a storage request from one of the plurality of virtual machines. In some embodiments, the allocation agent is a hypervisor executing on the computing system. In some embodiments, the computing system tracks utilizations of the storage device by the plurality of virtual machines, and based on the utilizations, enforces a quality of service level associated with one or more of the plurality of virtual machines.

Claims

1. A method, comprising:

a computing system providing a logical address space for a storage device to an allocation agent that is executable to allocate the logical address space to a plurality of virtual machines having access to the storage device, wherein the logical address space is larger than a physical address space of the storage device; and

the computing system processing a storage request from one of the plurality of virtual machines, wherein the storage request specifies a logical address within the logical address space.

2. The method of claim 1, wherein the logical address space is a sparse address space.

3. The method of claim 1, further comprising:

the computing system tracking utilizations of the storage device by the plurality of virtual machines; and

based on the utilizations, the computing system enforcing a quality of service level associated with one or more of the plurality of virtual machines.

4. The method of claim 1, wherein each of the plurality of virtual machines is allocated a respective logical block address (LBA) range within the logical address space, and wherein the method further comprises:

the computing system presenting a plurality of virtual functions to the virtual machines, wherein a first of the plurality of virtual functions services a request associated with a first of the allocated LBA ranges.

5. The method of claim 1, wherein the logical address space is determined based on a number of the plurality of virtual machines, and wherein the allocation agent is a hypervisor executing on the computing system.

6. The method of claim 5, wherein the logical address space is determined by a driver of the storage device, and wherein the driver receives the number of virtual machines from the hypervisor in response to formatting the storage device.

7. An apparatus, comprising:

an allocation module configured to allocate at least a portion of a logical address space for a storage device to a plurality of virtual machines managed by a hypervisor, wherein the logical address space is larger than a physical address space of the storage device, and wherein the allocation module is configured to allocate the portion by segregating the portion between the virtual machines;

a storage module configured to process a storage request received directly from a virtual machine, the storage request comprising a logical address determined by the virtual machine, wherein the logical address is from the allocated portion;

a translation module configured to translate the logical address to a physical address within the storage device.

8. The apparatus of claim 7, wherein the logical address is a relative logical address, and wherein the translation module is configured to translate the relative logical address to a corresponding physical address by applying an offset to the relative logical address.

9. The apparatus of claim 7, wherein the translation module is configured to maintain a map data structure having a set of translations associated with a first of the plurality of virtual machines;

and

wherein the apparatus is configured to instantiate a second virtual machine from the first virtual machine by duplicating the set of translations and associating the duplicate set of transitions with a range of the logical address space provided to the second virtual machine.

10. The apparatus of claim 7, wherein the allocation module is configured to:

receive an indication of a size for a virtual address space presented by a guest operating system within one of the plurality of virtual machines; and

present a logical address space such that a range provided to the virtual machine is at least as large as the size of the virtual address space.

11. The apparatus of claim 7, further comprising:

a quality of service (QoS) module configured to service requests to access the storage device in a manner that affords a QoS level to one or more of the plurality of virtual machines.

12. The apparatus of claim 11, wherein the QoS module is configured to determine a utilization of the storage device by the one or more virtual machines based on logical addresses specified by the requests, and wherein the QoS module is configured to service the requests based on the determined utilization.

13. The apparatus of claim 7, wherein the apparatus is a controller within the storage device, and wherein storage device is a solid-state device.

14. A non-transitory computer readable medium having program instructions stored thereon, wherein the program instructions are executable by a computing system to cause the computing system to perform operations comprising:

configuring a storage device such the storage device has a logical address space that is larger than a physical address space of the storage device; and

servicing requests for the storage device from a plurality of virtual machines allocated respective portions of the logical address space.

15. The computer readable medium of claim 14, wherein the respective portions are contiguous and non-overlapping ranges of logical addresses allocated by a hypervisor of the computing system, wherein a first of the respective portions has a different size than a second of the respective portions.

16. The computer readable medium of claim 14, wherein the servicing includes:

identifying a virtual machine associated with a given request; and

determining whether to service the request based on a utilization of the identified virtual machine relative to utilizations of other ones of the plurality of virtual machines.

17. The computer readable medium of claim 14, wherein the operations further comprise:

causing a virtual machine to be allocated a range of the logical address space, wherein the range has a size that is at least as large as a virtual address space supported by a guest operating system within the virtual machine; and

permitting the guest operating system to maintain one or more pages of the virtual address space within a swap on the storage device.

18. The computer readable medium of claim 14, wherein the operations further comprise:

saving a state of a virtual machine, wherein the saving includes;

duplicating a set of translations specifying physical addresses associated with data of the virtual machine;

associating the duplicate set of translations with a range of the logical address space that is different than a range of the logical address space allocated to the virtual machine; and

inhibiting garbage collection of the data associated with the set of translations.

19. The computer readable medium of claim 14, wherein the program instructions executable to cause the computing system to perform the configuring and the servicing are program instructions of a driver for the storage device, and wherein the driver is executable to receive the requests via a plurality of single root I/O virtualization (SR-IOV) virtual functions.

20. An apparatus, comprising:

a first means for storing data using a log-structure, wherein the first means has a physical address space; and

a second means for presenting a logical address space of the first means to a hypervisor that is executable to allocate the logical address space to a plurality of virtual machines having access to the first means, wherein the logical address space is larger than the physical address space.

21. The apparatus of claim 20, wherein the first means includes a solid-state storage array.