Technical data

64 ServerIron ADX Advanced Server Load Balancing Guide
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Other transparent cache switching options
2
High availability support
Because sessions are synced between ServerIron ADX devices, passive FTP for TCS also supports
the high availability (HA) topology. The most common HA setup is Active-Active mode. Figure 15
shows an example of a Layer 2 Active-Active setup.
FIGURE 15 Layer 2 Active-Active high availability setup
Asymmetric flow
The control and data traffic between a client and cache server or between a cache server and a
real server can be asymmetric, as described in Figure 16.
FIGURE 16 Asymmetric flow example
ServerIron ADX failover
Failover of the router or ServerIron ADX device is supported.
Configure VRRP on routers R1 and R2. Where R1 is the master or default gateway for both the
client and cache server, the flow will be as shown in Figure 17.
FIGURE 17 Normal flow before failover
Client
CIP
Real Server
RIP
Transparent
Cache Server
TIP
ServerIron ADX 1
R3 R4
R1 R2
ServerIron ADX 2
Session Sync Link
Client R1 SI1 Cache Server SI2 R2 Client
Cache Server SI1 R3 Real Server R4 SI2 Cache Server
Or
Client R1 SI1 Cache Server SI1 R1 Client