Communication of diagnostic parameters of a data mirroring configuration from a storage controller to a host

Patent metadata

Field	Value
Publication number	US-11226880-B2
Application number	US-201816213797-A
Country	US
Kind code	B2
Filing date	Dec 7, 2018
Priority date	Dec 7, 2018
Publication date	Jan 18, 2022
Grant date	Jan 18, 2022

Abstract

A storage controller is configured to communicate with a host over a first storage area network. Data controlled via the storage controller is mirrored to another storage controller over a second storage area network. The storage controller receives a request from the host to provide read diagnostic parameters of the second storage area network. In response to receiving the request, the storage controller secures the read diagnostic parameters of the second storage area network. The storage controller transmits the read diagnostic parameters of the second storage area network to the host.

First claim

What is claimed is:

1. A method, comprising:
configuring a first storage controller to communicate with a host over a first storage area network that is not isolated from the host;
performing a synchronous mirroring of data controlled via the first storage controller to a second storage controller over a second storage area network that is comprised of a plurality of storage area networks including a plurality of paths, wherein the second storage area network is isolated from the host, and wherein a first type of request comprising Extended Link Services (ELS) commands over a Fibre Channel (FC) protocol allows the host to acquire read diagnostic parameters of the first storage area network but not of the second storage area network, and diagnostic data for the synchronous mirroring that are hidden by the first storage controller from the host are prevented from being retrieved by the ELS commands over the FC protocol;
receiving, by the first storage controller a second type of request from the host to provide the read diagnostic parameters of the second storage area network, wherein the second type of request comprises a set of Perform Subsystem Function (PSF), Device Server Option (DSO) and a read subsystem data command that allow the host to receive the read diagnostic parameters of the second storage area network; and
in response to receiving the second type of request, transmitting, by the first storage controller to the host the read diagnostic parameters of the plurality of paths that are available to be used for the synchronous mirroring of the data controlled by the first storage controller to the second storage controller, wherein the read diagnostic parameters of the plurality of paths indicate that a first path of the plurality of paths provides a superior communication path than a second path of the plurality of paths for the mirroring of the data, wherein the first path that provides the superior communication path is chosen over the second path for performing selected operations, and wherein the first storage controller prevents the first type of request from securing the read diagnostic parameters of the plurality of paths but allows the second type of request to secure the read diagnostic parameters of the plurality of paths.

2. The method of claim 1 , wherein the first storage controller isolates the second storage area network from the host and does not permit the host to directly secure read diagnostic parameters of the second storage area network without transmitting the second type of request from the host to the first storage controller to provide the read diagnostic parameters of the second storage area network.

3. The method of claim 1 , the read diagnostic parameters allow fault isolation in the second storage area network.

4. The method of claim 1 , wherein the synchronous mirroring is via synchronous replication in which a write from the host is complete only after the write is completed on volumes of both the first and the second storage controller.

5. The method of claim 1 , wherein additional storage area networks are also used for the synchronous mirroring of the data, and wherein different ports are used for the mirroring of the data within a same storage area network.

6. The method of claim 1 , wherein the second storage area network is comprised of a first mirroring storage area network that provides the first path from the first storage controller to the second storage controller, and a second mirroring storage area network that provides the second path from the first storage controller to the second storage controller, wherein the first mirroring storage area network synchronously mirrors data from the first storage controller to the second storage controller via the first path, and wherein the second mirroring storage area network synchronously mirrors data from the first storage controller to the second storage controller via the second path.

7. The method of claim 1 , wherein FC commands used by the first type of request allows an operating system of the host to retrieve the read diagnostic parameters of the first storage area network coupling the host to the first storage controller, and wherein the second type of request uses an extension to the operating system of the host by using at least the PSF, the DSO and the read subsystem data command to retrieve the read diagnostic parameters of the first path and the second path.

8. The method of claim 1 , wherein the set of PSF, SSO, Device Server Option (DSO) and the read subsystem data command is configured in an operating system in the second type of request to secure read diagnostic parameters for the second storage area network that is not visible to the host in the FC protocol, wherein the FC protocol is used by the first storage area network and the second storage area network.

9. A first storage controller, comprising:
a memory; and
a processor coupled to the memory, wherein the processor performs operations, the operations comprising:
configuring the first storage controller to communicate with a host over a first storage area network that is not isolated from the host;
performing a synchronous mirroring of data controlled via the first storage controller to a second storage controller over a second storage area network that is comprised of a plurality of storage area networks including a plurality of paths, wherein the second storage area network is isolated from the host, and wherein a first type of request comprising Extended Link Services (ELS) commands over a Fibre Channel (FC) protocol allows the host to acquire read diagnostic parameters of the first storage area network but not of the second storage area network, and diagnostic data for the synchronous mirroring that are hidden by the first storage controller from the host are prevented from being retrieved by the ELS commands over the FC protocol;
receiving, by the first storage controller a second type of request from the host to provide the read diagnostic parameters of the second storage area network, wherein the second type of request comprises a set of Perform Subsystem Function (PSF), Device Server Option (DSO) and a read subsystem data command that allow the host to receive the read diagnostic parameters of the second storage area network; and
in response to receiving the second type of request, transmitting, by the first storage controller to the host the read diagnostic parameters of the plurality of paths that are available to be used for the synchronous mirroring of the data controlled by the first storage controller to the second storage controller, wherein the read diagnostic parameters of the plurality of paths indicate that a first path of the plurality of paths provides a superior communication path than a second path of the plurality of paths for the mirroring of the data, wherein the first path that provides the superior communication path is chosen over the second path for performing selected operations, and wherein the first storage controller prevents the first type of request from securing the read diagnostic parameters of the plurality of paths but allows the second type of request to secure the read diagnostic parameters of the plurality of paths.

10. The first storage controller of claim 9 , wherein the first storage controller isolates the second storage area network from the host and does not permit the host to directly secure read diagnostic parameters of the second storage area network without transmitting the second type of request from the host to the first storage controller to provide the read diagnostic parameters of the second storage area network.

11. The first storage controller of claim 9 , the read diagnostic parame

Assignees

• IBM

Inventors

• Riedy Dale F
• Compton Scott B
• Candelaria Susan K
• Hathorn Roger G
• Yudenfriend Harry M

Classifications

• G06F11/3034

  where the computing system component is a storage system, e.g. DASD based or network based (digital input from or digital output to record carriers G06F3/06; digital recording or reproducing G11B20/18; 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], H04L67/1097) · CPC title

• G06F3/0635

  by changing the path, e.g. traffic rerouting, path reconfiguration · CPC title

• G06F3/061

  Improving I/O performance · CPC title

• G06F3/0617

  in relation to availability · CPC title

• G06F3/065

  Replication mechanisms · CPC title