Mirror Pair Replication Path

[Smith_K]

Is it possible to choose which path the mirrors replicate data on. I have two eseries direct attached on e0b that I would like to use for replication.

[Ontapforrum]

Following TR has a section on Mirroring requirements, not sure if that helps?

Page-15: Supported connections
https://www.netapp.com/pdf.html?item=/media/17133-tr4656pdf.pdf

[TravisFields · Accepted solution]

There is no way to specify a path for the mirror relationship, the port chosen for mirror traffic is determined based on the type of mirroring (synchronous or asynchroumous) and the protocol (FC or iSCSI). Each mirroring method and protocol has its own requirements and restrictions.

Requirements for using synchronous mirroring

Supported connections:

Communication for synchronous mirroring is supported only on controllers with Fibre Channel (FC) host ports. 

Synchronous mirroring uses the highest numbered FC host port on each controller on both the local storage array and the remote storage array. Controller host bus adapter (HBA) host port 4 is typically reserved for mirror data transmission.

Note: For more information on the requirements for synchronous mirroring please visit the link above.

Requirements for using asynchronous mirroring

Asynchronous mirroring uses the storage array’s host-side I/O ports to convey mirrored data from the primary side to the secondary side.

• Mirroring through a Fibre Channel (FC) interface:

  Each controller of the storage array dedicates its highest numbered FC host port to mirroring operations.

  If the controller has both base FC ports and host interface card (HIC) FC ports, the highest numbered port is on an HIC. Any host logged on to the dedicated port is logged out, and no host login requests are accepted. I/O requests on this port are accepted only from controllers that are participating in mirroring operations.

  The dedicated mirroring ports must be attached to an FC fabric environment that supports the directory service and name service interfaces. In particular, FC-AL and point-to-point are not supported as connectivity options between the controllers that are participating in mirror relationships.

• Mirroring through an iSCSI interface:

  Unlike FC, iSCSI does not require a dedicated port. When asynchronous mirroring is used in iSCSI environments, it is not necessary to dedicate any of the storage array’s front-end iSCSI ports for use with asynchronous mirroring; those ports are shared for both asynchronous mirror traffic and host-to-array I/O connections.

  The controller maintains a list of remote storage systems with which the iSCSI initiator attempts to establish a session. The first port that successfully establishes an iSCSI connection is used for all subsequent communication with that remote storage array. If communication fails, a new session is attempted using all available ports.

  iSCSI ports are configured at the array level on a port-by-port basis. Intercontroller communication for configuration messaging and data transfer uses the global settings, including settings for:

  • VLAN: Both local and remote systems must have the same VLAN setting to communicate

  • iSCSI listening port

  • Jumbo frames

  • Ethernet priority

Note: For more information on the requirements for asynchronous mirroring please visit the link above or review the documentation (pages 15-19) provided in the previous post.

[MitchBlackburn]

It is not possible to choose the port. If you are mirroring using FC, the highest number FC port is taken.

Unlike FC, iSCSI does not require a dedicated port. The controller maintains a list of remote storage systems with which the iSCSI initiator attempts to establish a session. The first port that successfully establishes an iSCSI connection is used for all subsequent communication with that remote storage system. If communication fails, a new session is attempted using all available ports.

Please find below doc on netapp.com.
SANtricity synchronous and asynchronous mirroring (11.61 and earlier) | TR-4656 (netapp.com)<>