VIRTUALIZATION INTERMEDIARY/VIRTUAL MACHINE GUEST OPERATING SYSTEM COLLABORATIVE SCSI PATH MANAGEMENT

• US 20110239213A1
• Filed: 03/25/2010
• Published: 09/29/2011
• Est. Priority Date: 03/25/2010
• Status: Active Grant

• Current Assignee: Vmware LLC (Broadcom, Inc.)
• Original Assignee: VMware, Inc. (Broadcom, Inc.)
• Inventors: GOGGIN, Edward Joseph, ASWANI, Sanjana, PATALE, Vibhor Arunkumar, BAJAJ, Rupesh, SUBRAMANIAN, Hariharan
• Granted Patent: US 8,719,817 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 9/45558 Hypervisor-specific management and integration aspects

Abstract

A method of direct access by a virtual machine (VM) running on a host machine to physical storage via a virtual function (VF) running on an input/output (IO) adapter comprising: providing by a virtualization intermediary running on the host machine an indication of an active path associated with a virtual storage device; obtaining by a guest driver running within a guest operating system of the VM the stored indication of the active path from the shared memory region; dispatching an IO request by the guest driver to the VF that includes an indication of the active path; and sending by the VF an IO request that includes the indicated active path.

Claims

1. A method of direct access by a virtual machine (VM) running on a host machine to physical storage via a virtual function (VF) running on an input/output (IO) adapter comprising:

storing by a virtualization intermediary an indication of an active path associated with a virtual storage device to a memory region shared by the guest driver and the virtualization intermediary;

obtaining by the guest driver the stored indication of the active path from the shared memory region;

dispatching an IO request by the guest driver to the VF that includes an indication of the active path; and

sending by the VF an IO request that includes the indicated active path.

2. The method of claim 1,

wherein the active path information includes a physical SCSI target identifier and a physical LUN identifier.

3. The method of claim 1,

wherein the IO request sent by the VF includes a SCSI path triplet including a virtual SCSI initiator, a physical SCSI target and a physical LUN in which the VF serves as the virtual SCSI initiator.

4. The method of claim 1,

wherein sending the IO request by the VF includes sending using a transport level protocol in which the VF is identified by a virtual port.

5. The method of claim 4,

wherein the transport level protocol includes at least one of SAS, fibre channel or iSCSI.

6. The method of claim 1 further including:

determining by the guest driver whether an indication of the active path associated with the identified a virtual storage device is provided in a cache storage associated with the guest driver; and

performing the act of requesting by the guest driver from the virtualization intermediary when the cache storage does not contain an indication of the active path; and

obtaining by the guest driver the stored indication of the active path from the cache storage when the cache storage does contain indication of the active path.

7. The method of claim 1 further including:

storing the obtained indication of the active path to a cache storage associated with the guest driver.

8. The method of claim 1 further including:

requesting from a multipath service associated with the virtualization intermediary an indication of an active path currently associated with the identified virtual storage device;

wherein storing by the virtualization intermediary includes storing an active path indicated by the multipath service.

9. The method of claim 8,

wherein the multipath service identifies multiple paths associated with the physical storage region associated with the virtualization intermediary and keeps track of which of those multiple paths currently is the active path.

10. The method of claim 1 further including:

receiving by a guest driver from a guest operating system of the VM an IO request that identifies a virtual storage device;

requesting by the guest driver from the virtualization intermediary an indication of an active path to a physical storage region within the physical storage that is associated with the identified virtual storage device;

wherein the act of storing by the virtualization intermediary is responsive to the request by the guest driver.

11. The method of claim 10 further including:

providing by an application running on the guest operating system of the VM an IO request; and

determining by the guest operating system a virtual storage device to service the IO request.

12. A method of direct access by a virtual machine (VM) running on a host machine to physical storage via a virtual function (VF) running on an input/output (IO) adapter comprising:

identifying by a virtualization intermediary running on the host machine a change in an active path associated with a virtual storage device allocated to the VM;

storing by the virtualization intermediary an indication of the changed active path to a memory region shared by a guest driver of the VM and by the virtualization intermediary;

sending by the virtualization intermediary a notification to the guest driver of the change in active path associated with the virtual storage device; and

obtaining by the guest driver the stored indication of the active path from the shared memory region.

13. The method of claim 12 further including:

storing the obtained indication of the active path to a cache storage associated with the guest driver.

14. The method of claim 13 further including:

receiving by a guest driver from a guest operating system of the VM an IO request that identifies a virtual storage device;

obtaining by the guest driver the stored indication of the active path from the cache storage;

dispatching an IO request by the guest driver to the VF that includes an indication of the active path obtained from the shared memory region; and

sending by the VF an IO request that includes the indicated active path.

15. The method of claim 12 wherein,

wherein changing by a virtualization intermediary includes changing my a multipath process running on the host machine within the virtualization intermediary.

16. An article of manufacture including a machine readable storage device encoded with computer readable instructions to cause a machine to perform a process to direct access by a virtual machine (VM) running on a host machine to physical storage via a virtual function (VF) running on an input/output (IO) adapter, the process comprising:

storing by a virtualization intermediary an indication of an active path associated with a virtual storage device to a memory region shared by the guest driver and the virtualization intermediary;

obtaining by the guest driver the stored indication of the active path from the shared memory region;

dispatching an IO request by the guest driver to the VF that includes an indication of the active path; and

sending by the VF an IO request that includes the indicated active path.

17. An article of manufacture including a machine readable storage device encoded with computer readable instructions to cause a machine to perform a process to direct access by a virtual machine (VM) running on a host machine to physical storage via a virtual function (VF) running on an input/output (IO) adapter, the process comprising:

identifying by a virtualization intermediary running on the host machine a change in an active path associated with a virtual storage device allocated to the VM;

storing by the virtualization intermediary an indication of the changed active path to a memory region shared by a guest driver of the VM and by the virtualization intermediary;

sending by the virtualization intermediary a notification to the guest driver of the change in active path associated with the virtual storage device; and

obtaining by the guest driver the stored indication of the active path from the shared memory region.

18. An apparatus to provide direct access by a virtual machine (VM) running on a host machine to physical storage via a virtual function (VF) running on an input/output (IO) adapter comprising;

means for communicating active path information from a virtualization intermediary running on the host machine to a guest driver running within a guest operating system of the VM in response to a request from the guest driver to the virtualization intermediary; and

means for reporting active path information from the virtualization intermediary to the guest driver in response to a change in active path information within the virtualization intermediary.