Operating local caches for a shared storage device

• US 10,241,913 B2
• Filed: 01/20/2016
• Issued: 03/26/2019
• Est. Priority Date: 01/20/2016
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Crasta, Alol Antony, Patil, Harshal S., Pillai, Kishorekumar G., Raisch, Christoph, Ranjan, Nishant
• Primary Examiner(s): Taylor, Nicholas R
• Assistant Examiner(s): Kim, Chong G
• Application Number:
  US15/001,274
• Publication Number:
  US 20170208149A1
• Time in Patent Office: 1,161 Days
• Field of Search: 709226
• CPC Class Codes: G06F 12/0813 with a network or matrix configuration
• CPC Class Codes: G06F 12/0815 Cache consistency protocols
• CPC Class Codes: G06F 2212/1016 Performance improvement
• CPC Class Codes: G06F 2212/154 Networked environment
• CPC Class Codes: G06F 2212/222 Non-volatile memory
• CPC Class Codes: G06F 2212/263 Network storage, e.g. SAN or NAS
• CPC Class Codes: G06F 3/06 Digital input from, or digital output to, record carriers , e.g. RAID, emulated record carriers or networked record carriers
• CPC Class Codes: G06F 3/0607 by facilitating the process of upgrading existing storage systems, e.g. for improving compatibility between host and storage device
• CPC Class Codes: G06F 3/0647 Migration mechanisms
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: H04L 65/611 for multicast or broadcast systems for broadcast or conference H04L12/18; arrangements for broadcast or distribution combined with broadcast H04H20/00; arrangements for broadcast applications with a direct linkage to broadcast information or to broadcast space-time H04H60/00; selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS], H04W4/06
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching

Abstract

Aspects include creating a network multicast group in a storage area network (SAN) for a first computer system and a second computer system that are connected by the SAN and that each include a local cache for a shared storage device. Prior to one of the first or second computer system writing write data to the shared storage device: the write data is written to the local cache of the one of the first or second computer system; the write data is sent to the multicast group; based on the send operation completing, the write data is written to the shared storage device; and based on the write operation completing, the write completion is signaled to an operating system or hypervisor of the first and second computer systems.

Claims

1. A system comprising:

a memory having computer readable instructions; and

a processing unit for executing the computer readable instructions, the computer readable instructions including;

creating a network multicast group in a storage area network (SAN) for a plurality of computer systems that are connected by the SAN, the plurality of computer systems comprising at least three computer systems including a first computer system and a second computer system, the plurality of computer systems each comprising a local cache for a shared storage device;

prior to one of the first or second computer system writing write data to the shared storage device;

writing the write data to the local cache of the one of the first or second computer system;

sending the write data to the plurality of computer systems in the multicast group;

based on the send operation completing, writing the write data to the shared storage device; and

based on the write operation completing, signaling write completion to an operating system or hypervisor of the first and second computer systems; and

based on one of the first or second computer system requesting a read of read data from the shared storage device;

waiting for parallel write operations to complete for the read data in the plurality of computer systems in the multicast group;

retrieving the read data from the local cache of the one of the first or second computer system based on the read data being available in the local cache of the one of the first or second computer system; and

retrieving the read data from the shared storage device and storing the read data in the local cache of the one of the first or second computer system based on the read data not being available in the local cache of the one of the first or second computer system.

2. The system of claim 1, wherein a cache management component of each of the first and second computer systems performs the creating, writing and retrieving from the local cache and the shared storage device.

3. The system of claim 1, wherein the multicast group is attributed to the storage device.

4. The system of claim 1, wherein the SAN comprises at least one storage controller for access to the shared storage device.

5. The system of claim 4, wherein the instructions further include distributing the write data through the network adapter with at least one multicast group per storage device.

6. The system of claim 1, wherein the multicast group is identified by at least one of a world-wide unique identifier of the corresponding network adapter and a unique identifier of the storage device.

7. A computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions executable by a processor to cause the computer processor to perform:

creating a network multicast group in a storage area network (SAN) for a plurality of computer systems that are connected by the SAN, the plurality of computer systems comprising at least three computer systems including a first computer system and a second computer system, the plurality of computer systems each comprising a local cache for a shared storage device;

prior to one of the first or second computer system writing write data to the shared storage device;

writing the write data to the local cache of the one of the first or second computer system;

sending the write data to the plurality of computer systems in the multicast group;

based on the send operation completing, writing the write data to the shared storage device; and

based on the write operation completing, signaling write completion to an operating system or hypervisor of the first and second computer systems; and

based on one of the first or second computer system requesting a read of read data from the shared storage device;

waiting for parallel write operations to complete for the read data in the plurality of computer systems in the multicast group;

retrieving the read data from the local cache of the one of the first or second computer system based on the read data being available in the local cache of the one of the first or second computer system; and

retrieving the read data from the shared storage device and storing the read data in the local cache of the one of the first or second computer system based on the read data not being available in the local cache of the one of the first or second computer system.

8. The computer program product of claim 7, wherein a cache management component of each of the first and second computer systems performs the creating, writing and retrieving from the local cache and the shared storage device.

9. The computer program product of claim 7, wherein the multicast group is attributed to the storage device.

10. The computer program product of claim 7, wherein the SAN comprises at least one storage controller for access to the shared storage device.