Transparent host-side caching of virtual disks located on shared storage

Patent metadata

Field	Value
Publication number	US-9454487-B2
Application number	US-201313922985-A
Country	US
Kind code	B2
Filing date	Jun 20, 2013
Priority date	Aug 27, 2012
Publication date	Sep 27, 2016
Grant date	Sep 27, 2016

Abstract

Techniques for using a host-side cache to accelerate virtual machine (VM) I/O are provided. In one embodiment, the hypervisor of a host system can intercept an I/O request from a VM running on the host system, where the I/O request is directed to a virtual disk residing on a shared storage device. The hypervisor can then process the I/O request by accessing a host-side cache that resides one or more cache devices distinct from the shared storage device, where the accessing of the host-side cache is transparent to the VM.

First claim

What is claimed is:

1. A method for using a host-side cache to accelerate virtual machine (VM) I/O, the method comprising:
intercepting an I/O request from a VM running on the host system, the I/O request being directed to a virtual disk residing on a shared storage device; and
processing the I/O request by accessing a host-side cache distinct from the shared storage device, wherein a guest operating system of the VM is unware that the host-side cache is being accessed as part of the processing,
wherein the host-side cache is spread across a plurality of cache devices, and
wherein the plurality of cache devices are pooled into a single logical resource by applying a common file system to the plurality of cache devices.

2. The method of claim 1 wherein processing the I/O request by accessing the host-side cache comprises invoking a caching module that has been preconfigured for use with the VM or the virtual disk.

3. The method of claim 2 wherein the caching module is a modular component of the hypervisor that is implemented by a third-party developer.

4. The method of claim 1 wherein the plurality of cache devices are heterogeneous devices.

5. The method of claim 1 wherein the VM or the virtual disk is allocated a portion of the host-side cache when the VM is powered on, the allocated portion having a preconfigured minimum size and a preconfigured maximum size.

6. The method of claim 5 wherein the allocated portion is freed when the VM is powered off or migrated to another host system.

7. A host system comprising:
a processor; and
a non-transitory computer readable medium having stored thereon program code that, when executed by the processor, causes the processor to:
intercept an I/O request from a VM running on the host system, the I/O request being directed to a virtual disk residing on a shared storage device; and
process the I/O request by accessing a host-side cache distinct from the shared storage device, wherein a guest operating system of the VM is unware that the host-side cache is being accessed as part of the processing,

wherein the host-side cache is spread across a plurality of cache devices, and
wherein the plurality of cache devices are pooled into a single logical resource by applying a common file system to the plurality of cache devices.

8. The host system of claim 7 wherein the program code that causes the processor to process the I/O request by accessing the host-side cache comprises program code that causes the processor to invoke a caching module that has been preconfigured for use with the VM or the virtual disk.

9. The host system of claim 8 wherein the caching module is a modular component that is implemented by a third-party developer.

10. The host system of claim 7 wherein the plurality of cache devices are heterogeneous devices.

11. The host system of claim 7 wherein the VM or the virtual disk is allocated a portion of the host-side cache when the VM is powered on, the allocated portion having a preconfigured minimum size and a preconfigured maximum size.

12. The host system of claim 11 wherein the allocated portion is freed when the VM is powered off or migrated to another host system.

13. A non-transitory computer readable storage medium having stored thereon computer software executable by a processor of a host system, the computer software embodying a method for using a host-side cache to accelerate VM I/O, the method comprising:
intercepting an I/O request from a VM running on the host system, the I/O request being directed to a virtual disk residing on a shared storage device; and
processing the I/O request by accessing a host-side cache distinct from the shared storage device, wherein a guest operating system of the VM is unware that the host-side cache is being accessed as part of the processing,
wherein the host-side cache is spread across a plurality of cache devices, and
wherein the plurality of cache devices are pooled into a single logical resource by applying a common file system to the plurality of cache devices.

14. The non-transitory computer readable storage medium of claim 13 wherein processing the I/O request by accessing the host-side cache comprises invoking a caching module that has been preconfigured for use with the VM or the virtual disk.

15. The non-transitory computer readable storage medium of claim 14 wherein the caching module is a modular component that is implemented by a third-party developer.

16. The non-transitory computer readable storage medium of claim 13 wherein the plurality of cache devices are heterogeneous devices.

17. The non-transitory computer readable storage medium of claim 13 wherein the VM or the virtual disk is allocated a portion of the host-side cache when the VM is powered on, the allocated portion having a preconfigured minimum size and a preconfigured maximum size.

18. The non-transitory computer readable storage medium of claim 17 wherein the allocated portion is freed when the VM is powered off or migrated to another host system.

Assignees

• Vmware Inc

Inventors

• Phelan Thomas A
• Rawat Mayank
• Liu Deng
• Madnani Kiran
• Bandarupalli Sambasiva

Classifications

• G06F2212/1024

  Latency reduction · CPC title

• G06F9/455

  Emulation; Interpretation; Software simulation, e.g. virtualisation or emulation of application or operating system execution engines · CPC title

• G06F12/0871

  Allocation or management of cache space · CPC title

• G06F3/0631

  by allocating resources to storage systems · CPC title

• G06F12/0866 Primary

  for peripheral storage systems, e.g. disk cache · CPC title