IBM System storage DS6000 Series, Redbooks

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DS6000 Series: Concepts and Architecture
Figure 10-2 DS CLI Copy Services command flow
DS8000 split network
One thing that you may notice about Figure 10-2 is that the S-HMC has different network
interfaces. The external network interface is an Ethernet port that must be accessible from the
open systems host network interface. The dual, internal network interfaces use the two
internal Ethernet switches within the DS8000 base frame to deliver the commands to the
relevant storage server. This means that the DS8000 itself is not on the same network as the
open systems host. The S-HMC therefore acts as a bridge between the
external
server
network and the
internal
DS8000 network.
Clearly a major benefit of this setup is that the internal network within the DS8000 has no
single points of failure. By using a second S-HMC it is possible to create a completely
redundant communications network for the DS CLI traffic between a host server and the
DS8000 servers.
DS6000 command flow
If a DS6000 is used, commands are instead issued to the DS Storage Manager PC, that has
to be supplied and set up when a DS6000 is installed. The DS Storage Manager PC then
issues the commands to the relevant DS6000 controller. This command flow is depicted in
Figure 10-3 on page 201.
Open systems
host
Cluster 1
CS Client
Cluster 2
ESS 800
CS Client
CS Server B
Server 0
Server 1
DS8000
CLI interface
CLI interface
Storage HMC
CS Server A
Network interface
ESS CLI software DS CLI software
CLI script
Dual
internal
network
interfaces
CLI
interpreter
External
network
interface