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Dell EMC VxRail Multirack Deployment Guide
8
VMware vSAN stretched clusters
Stretched clusters extend a vSAN cluster from a single site (geographical location, floors, or racks), to two
sites for a higher level of availability. Stretched clusters are typically deployed in environments where the
distance between the sites is limited, such as metropolitan or campus environments.
In this Deployment Guide, VMware vSAN stretched clusters is deployed using the two racks containing the
eight total VxRail nodes. Each rack is configured as a separate fault domain achieving rack failure tolerance.
Figure 17 shows a diagram illustrating the flow between the three locations: Rack 1, Rack 2, and Rack 3.
Rack 3 contains the vSAN witness appliance, whose purpose is to host the witness components of virtual
machine objects. Rack 1 and Rack 2 have already been configured using VXLANs stretched the Layer 2 (L2)
domains between the two racks. Traffic to the vSAN witness appliance is done through L3 routing between
the two data centers.
Note:
For more information about how routing between tunnels is configured, see
Appendix A
.
DCI
10.255.255.248/29
vSAN witness
appliance
Mgmt VLAN: 1631
vSAN VLAN: 1633
Witness VLAN: 1634
Mgmt VLAN: 1631
vSAN VLAN: 1633
Witness VLAN: 1634
Mgmt VLAN: 1731
Witness VLAN: 1734
Rack 2
(Active)
Rack 1
(Active)
Rack 3
Edge Router
Edge Router
VXLAN
Primary DC
172.16.31.0/24
Secondary DC
172.17.31.0/24
vSAN stretched cluster network diagram
Note:
The vSAN witness appliance requires available through routing. The witness appliance can be located
in the Primary data center, depending on requirements.