IBM TotalStorage DS6000 Series - Manual (Page 223)

Chapter 10. DS CLI 199
Figure 10-1 Command flow for ESS 800 Copy Services commands
A CS server is now able to manage up to eight F20s and ESS 800s. This means that up to
sixteen clusters can be clients of the CS server. All FlashCopy and remote copy commands
are sent to the CS server which then sends them to the relevant client on the relevant ESS.
DS CLI command flow
Scripts that invoke DS CLI commands issue those commands to the installed DS CLI
software on the open systems host. If the command is intended for an ESS 800 volume, then
the DS CLI software sends it to the CS server on the ESS 800. If, however, the command is
intended for a DS8000, the command is issued to the CLI interpreter of the Storage Hardware
Management Console (S-HMC). The S-HMC then interprets the command and issues it to
the relevant server in the relevant DS8000 using the redundant internal network that connects
the S-HMCs to the DS8000.
Secure sockets
All DS CLI traffic is encrypted using SSL (secure sockets layer). This means that all traffic
between the host server that is running the DS CLI client and the DS CLI server (for example,
the S-HMC or the ESS 800 cluster) is secure, including passwords and userids.
TCP/IP ports
DS CLI servers (such as an S-HMC) use a fixed number of TCP/IP ports to listen on. These
ports are listed in Chapter 8, “Configuration planning” on page 125. This is important for
planning considerations, where a firewall may exist between the client and the server.
Open systems
host
Cluster 1
CS Client
Cluster 2
ESS 800
CS Client
CS Server B CS Server A
Network interface
ESS CLI software ESS CS CLI software
CLI script