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

Patent metadata

Field	Value
Publication number	US-2016246503-A1
Application number	US-201615145109-A
Country	US
Kind code	A1
Filing date	May 3, 2016
Priority date	Aug 27, 2012
Publication date	Aug 25, 2016
Grant date	—

Abstract

Techniques for using a cache to accelerate virtual machine (VM) I/O are provided. In one embodiment, 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 host system can then process the I/O request by accessing a cache that resides on one or more cache devices directly attached to the host system, where the accessing of the cache is transparent to the VM.

First claim

What is claimed is:

1 . A method for using a cache to accelerate virtual machine (VM) I/O, the method comprising:
intercepting an I/O request from a VM running on a 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 cache that resides on one or more cache devices directly attached to the host system, the accessing of the cache being transparent to the VM.

2 . The method of claim 1 wherein processing the I/O request by accessing the 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 that is implemented by a third-party developer.

4 . The method of claim 1 wherein the cache is spread across a plurality of cache devices that are pooled into a single logical resource by applying a common file system to the plurality of cache devices.

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

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

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

8 . The method of claim 1 wherein the one or more cache devices are distinct from the shared storage device.

9 . 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 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 cache that resides on one or more cache devices directly attached to the host system, the accessing of the cache being transparent to the VM.

10 . The non-transitory computer readable storage medium of claim 9 wherein processing the I/O request by accessing the cache comprises invoking a caching module that has been preconfigured for use with the VM or the virtual disk.

11 . The non-transitory computer readable storage medium of claim 10 wherein the caching module is a modular component that is implemented by a third-party developer.

12 . The non-transitory computer readable storage medium of claim 9 wherein the cache is spread across a plurality of cache devices that are pooled into a single logical resource by applying a common file system to the plurality of cache devices.

13 . The non-transitory computer readable storage medium of claim 12 wherein the plurality of cache devices are heterogeneous devices.

14 . The non-transitory computer readable storage medium of claim 9 wherein the VM or the virtual disk is allocated a portion of the cache when the VM is powered on, the allocated portion having a preconfigured minimum size and a preconfigured maximum size.

15 . The non-transitory computer readable storage medium of claim 14 wherein the allocated portion is freed when the VM is powered off or migrated to another host system.

16 . The non-transitory computer readable storage medium of claim 9 wherein the one or more cache devices are distinct from the shared storage device.

17 . A host system comprising:
a processor; one or more cache devices; 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 cache that resides on the one or more cache devices, the accessing of the cache being transparent to the VM.

18 . The host system of claim 17 wherein the program code that causes the processor to process the I/O request by accessing the 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.

19 . The host system of claim 18 wherein the caching module is a modular component that is implemented by a third-party developer.

20 . The host system of claim 17 wherein the cache is spread across a plurality of cache devices that are pooled into a single logical resource by applying a common file system to the plurality of cache devices.

21 . The host system of claim 20 wherein the plurality of cache devices are heterogeneous devices.

22 . The host system of claim 17 wherein the VM or the virtual disk is allocated a portion of the cache when the VM is powered on, the allocated portion having a preconfigured minimum size and a preconfigured maximum size.

23 . The host system of claim 22 wherein the allocated portion is freed when the VM is powered off or migrated to another host system.

24 . The host system of claim 17 wherein the one or more cache devices are distinct from the shared storage device.

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

• G06F12/0866 Primary

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

• G06F9/45558

  Hypervisor-specific management and integration aspects · CPC title

• G06F2009/45579

  I/O management, e.g. providing access to device drivers or storage · CPC title