Planning for a stretched topology system
You can plan to meet the requirements of a stretched topology system.
Before you begin
- Each node of an I/O group must be at a different site (location or power phase).
- There must be managed disks at each site.
- There must be managed disks at a third site for quorum disks.
- There must be enough fibre optic connections between the nodes on each site and the managed disks on the third site.
- The site attribute must be set to 1, 2 or 3 for each controller before the system topology can be set to stretched.
Note: SAN Volume Controller 2145-24F
expansion enclosures are not supported
with stretched system topology.
Connections
- Nodes that are in the same I/O group and separated by more than 100 meters (109 yards) must use longwave Fibre Channel connections. A longwave small form-factor pluggable (SFP) transceiver can be purchased as an optional component, and must be one of the longwave SFP transceivers that are listed at the following website:
- Avoid using inter-switch links (ISLs) in paths between nodes and external storage systems.