SCALABLE STORAGE FOR VIRTUAL MACHINES

• US 20120290630A1
• Filed: 05/13/2011
• Published: 11/15/2012
• Est. Priority Date: 05/13/2011
• Status: Active Grant

• Current Assignee: Nexenta by DDN, Inc.
• Original Assignee: Nexenta Systems Incorporated (DataDirect Networks Incorporated)
• Inventors: AIZMAN, Alexander, BESTLER, Caitlin
• Granted Patent: US 8,812,566 B2
• Time in Patent Office: Days
• US Class Current: 707/827
• CPC Class Codes: G06F 16/188 Virtual file systems

Abstract

A method and system is disclosed for providing storage services to Virtual Machines (VMs) and the Hypervisor Platforms that host them. NAS referrals are used to control selection of NAS proxy servers that are optimized for the support of VMs and the Hypervisor Platforms accessing directories that are exclusively used in conjunction of a single VM. Referrals are dynamically controlled in a manner specific to the target environment to provide an optimal combination of local and network storage in support of VMs. A method of using named attributes allows referrals to subsets of a directory. The overhead of using a NAS proxy is tailored to the smallest set of accesses required to gain beneficial result from the use of local storage, and using direct access to shared network storage when local storage is not allocated. Most of the new suggested techniques are transparent to the existing NAS clients; some techniques may require modification of the NAS client software.

Claims

1. A system comprising:

Federated File System (Federated FS), the Federated FS comprising one or more network attached storage (NAS) file servers that stores directory sets that are exclusive to one or more virtual machines (VMs);

NAS Virtualization Management system (NAS VMS), which interfaces with a Virtualization Management system; and

one or more NAS clients associated with the VMs and optionally enhanced to understand extended semantics for controlling NAS referrals.

2. The system of claim 1, further comprising at least one NAS server providing storage services to one or more VMs and Hypervisor Platforms hosting those VMs.

3. The system of claim 1, further comprising at least one proxy NAS server (the VM Storage Proxy) for providing specialized services to one or more virtual machines and the Hypervisor Platforms supporting the one or more VMs.

4. The system of claim 3 which includes scalable storage of files and directories associated with VMs, wherein the required control over NAS referrals and local storage caching may be exercised by the VM Storage Proxy itself and/or the NAS VMS.

7. The method of claim 4, wherein a specialized NAS proxy server is designated as a VM Storage Proxy.

8. The method of claim 7, wherein the VM Storage Proxy exercises control over a VM Private Directory Set.

9. The method of claim 7, wherein the referral/redirection references a VM Storage Proxy L3 address on an Internal Network accessible only by the Hypervisor Platforms the VM Storage Proxy is supporting, and the VMs running on those Hypervisor Platforms.

10. The method of claim 7, wherein VM Storage Proxy collaborates with Virtualization Management to optimize load balancing decisions when assigning VMs to hosts.

11. The method of claim 8, wherein a VM Private Directory Set includes directories within the global namespace of the Federated FS associated exclusively with a specific VM.

12. The method of claim 8, wherein the VM Storage Proxy obtains exclusive control over a VM Private Directory Set prior to starting to exercise control of referrals of the directories within it.

13. The method of claim 8, which includes optimizing access to the directories of the VM Private Directory Set with respect to the corresponding NAS Client, which may be one of the following:

a) the Hypervisor Platform, b) VM Storage Proxy itself, or c) the VM itself.

14. The method of claim 12, wherein the VM Storage Proxy and Federated FS servers collaborate to refer a directory within a VM Private Directory Set via a NAS exclusive delegation or an exclusive opportunistic lock (oplock).

15. The method of claim 12, wherein the VM Storage Proxy and Federated FS collaborate to refer a portion of a directory rather than the directory as a whole.

16. The method of claim 12, wherein the VM Storage Proxy does not respond to any packet received on the Internal Network from any VM'"'"'s L3 address until the transfer of control for that VM'"'"'s private directory to the VM Storage Proxy is complete.

17. The method of claim 10, wherein the VM Storage Proxy receives notifications of VM migrations, launches and shutdowns from Virtualization Management System (NAS VMS).

18. The method of claim 14, wherein release of the claim on a directory by the VM Storage Proxy results in the referral or redirection of that directory being reverted to its normal setting.

19. The method of claim 14, wherein a Federated FS server supporting automatic referral allows direct access to referred directories from:

(a) the VM Storage Proxy itself;

(b) VMs or other VM Storage Proxies enabled by Partial Referrals;

(c) management-plane readers granted read-only access in a manner that does not disrupt the other clients.

20. The method of claim 19, wherein Federated FS servers supporting automatic referral issue referrals/redirects for a claimed directory only to the authorized VM and Hypervisor Platform, and refuse access to any other client.

21. The method of claim 14, wherein the referral/redirection references VM Storage Proxy L3 address on the Public Network dynamically assigned by the NAS VMS utilizing notifications of VMs assigned to each Hypervisor Platform and profile information on each VM obtained from the Virtualization Management system.

22. The method of claim 14, wherein the VM Storage Proxy performs Selective Block Caching, with only portions of the blocks comprising a file stored locally.

23. The method of claim 12, wherein the VM Storage Proxy relies upon the source address of packets it receives on its Internal Network to reliably identify the NAS clients.

24. The method of claim 14, wherein the VM Storage Proxy relays operations on uncached files to the Federated FS, subject to access validation by the VM Storage Proxy.

25. The method of claim 14, wherein the VM Storage Proxy provides partial referrals to NAS clients, by publishing sets of Partial Referral named attributes, each specifying subset of files from a given partially referred directory.

26. The method of claim 24, wherein the VM Storage Proxy tracks the locations of sections of files within the Federated FS even when having those files or portions of those files cached locally.

27. The method of claim 14, wherein the VM Storage Proxy supports NAS clients that do not understand a Partial Referral named attributes.

5. A method comprising:

storing directory sets that are exclusive to one or more virtual machines (VMs) in one or more network attached storage (NAS) servers in a Federated File System (Federated FS); and

associating one or more NAS clients with the VMs, wherein the NAS clients may be optionally enhanced to understand extended semantics for controlling the NAS references.

6. The method of claim 5, wherein the location of storage associated with VMs is flexibly chosen in a manner that is transparent to the NAS clients.

28. A VM Storage Proxy comprising:

a storage medium; and

a proxy network attached storage (NAS) server exercising control over selected directories within a Federated File System (Federated FS).

29. A system comprising:

at least one proxy network attached storage (NAS) server for providing specialized storage services to one or more virtual machines (VMs) and the Hypervisor Platforms hosting those VMs;

Federated File System (Federated FS), the Federated FS comprising one or more network attached storage (NAS) file servers that store directory sets that are exclusive to one or more VMs;

NAS Virtualization Management system (NAS VMS), which interfaces with a Virtualization Management system; and

one or more NAS Clients associated with one or more VMs and optionally enhanced to understand extended semantics for controlling NAS referrals.