Requirements for using synchronous mirroring

If you plan to use synchronous mirroring, keep the following requirements in mind.

SANtricity Unified Manager

To enable and configure mirroring between two arrays, you must use the Unified Manager interface. Unified Manager is installed on a host system along with the Web Services Proxy.

Storage arrays

Note: Mirroring is not available on the EF300 or EF600 storage array.
  • You must have two storage arrays.
  • Each storage array must have two controllers.
  • The two storage arrays must be discovered in Unified Manager.
  • Each controller in both the primary array and secondary array must have an Ethernet management port configured and must be connected to your network.
  • The storage arrays have a minimum firmware version of 7.84. (They can each run different OS versions.)
  • You must know the password for the local and remote storage arrays.
  • You must have enough free capacity on the remote storage array to create a secondary volume equal to or greater than the primary volume that you want to mirror.
  • Your local and remote storage arrays are connected through a Fibre Channel fabric.

Supported connections

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

Synchronous mirroring uses the highest numbered 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.

Mirrored volume candidates

  • RAID level, caching parameters, and segment size can be different on the primary and secondary volumes of a synchronous mirrored pair.
  • The primary and secondary volumes in a synchronous mirrored pair must be standard volumes. They cannot be thin volumes or snapshot volumes.
  • The secondary volume must be at least as large as the primary volume.
  • Only the primary volume may have snapshots associated with it and/or be the source or target volume in a volume copy operation.
  • A volume can participate in only one mirror relationship.
  • There are limits to the number of volumes that are supported on a given storage array. Make sure that the number of configured volumes on your storage array is less than the supported limit. When synchronous mirroring is active, the two reserved capacity volumes that are created count against the volume limit.

Reserved capacity

  • Reserved capacity is required for a primary volume and for a secondary volume for logging write information to recover from controller resets and other temporary interruptions.
  • The reserved capacity volumes are created automatically when synchronous mirroring is activated. Because both the primary volume and the secondary volume in a mirrored pair require reserved capacity, you must ensure that you have enough free capacity available on both storage arrays that are participating in the synchronous mirror relationship.

Drive Security feature

  • If you are using secure-capable drives, the primary volume and the secondary volume must have compatible security settings. This restriction is not enforced; therefore, you must verify it yourself.
  • If you are using secure-capable drives, the primary volume and the secondary volume should use the same drive type. This restriction is not enforced; therefore, you must verify it yourself.
    • If the primary volume uses Full Disk Encryption (FDE) drives, the secondary volume should use FDE drives.
    • If the primary volume uses Federal Information Processing Standards 140-2 (FIPS) validated drives, the secondary volume should use FIPS 140-2 validated drives.
  • If you are using Data Assurance (DA), the primary volume and the secondary volume must have the same DA settings.