Home > Integrated Products > VxRail > Guides > Planning Guide—VMware Cloud Foundation 5.x on VxRail > Multi-availability zones
A multi-available architecture offers additional protection above that for a standard or consolidated architecture. Each availability zone is isolated from other availability zones to protect against a data center or site failure, and to prevent the propagation of a failure across zones.
The nodes that support the underlying VxRail cluster are installed and cabled in racks in two isolated zones. A single VxRail stretched cluster is configured with the nodes in the two zones. In this architecture, the vSAN datastore is stretched across both zones with I-O synchronized across sites to ensure no data loss if an outage occurs.
The network between the two zones must offer low latency (less than 5 milliseconds) and sufficient bandwidth (minimum 10 Gbps). Therefore, availability zones can protect against a wide scale outage in a metro area, or more simply, two safety or fire sectors in the same large-scale data center.