If you plan to use synchronous mirroring, keep the following
requirements in mind.
ThinkSystem SAN Manager
To enable
and configure mirroring between two arrays, you must use the SAN Manager interface. SAN Manager is installed on a host system along with the Web
Services Proxy.
Storage arrays
- You must have two storage
arrays.
- Each storage array must
have two controllers.
- The two storage arrays must be discovered in SAN 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 11.50. (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.