Operating System Software User Manual

Checking RCIP Link Throughput and Latency
By default, the cli checkrclink command uses port 5001. There is, however, an optional
parameter that allows you to specify a different port number:
# checkrclink startclient <N:S:P> <dest_addr> <time> [<port>]checkrclink startserver
<N:S:P> [dest_addr> [<port>]]
Verify that the firewall settings allow the remote-copy systems access to TCP port 5001 (default)
NOTE: It is not advisable to use port 5785 as the TCP port used to run the checkrclink
command. Doing so can have an adverse effect on existing remote copy links.
Follow these steps to check link throughput and latency:
1. Ensure that the systems for which you are checking links are not displaying signs of saturation.
2. Starting with the backup system, issue the following command on a system in the remote-copy
pair (System2):
# cli checkrclink startserver <N:S:P> <dest_addr>
where:
• <N:S:P>—Interface from which to check the link, expressed as node:slot:port
• <dest_addr>—IP address on the target system
3. On the target system in the remote-copy pair (System1), issue the following command:
# cli checkrclink startclient <N:S:P> <dest_addr> <time>
where:
• <N:S:P>—Interface from which to check the link, expressed as node:slot:port
• <dest_addr>—IP address or WWN on the target system for which you are checking
the link
• <time>—Duration of the test in seconds
4. Issue the following command on the first target system in the remote-copy pair (System2, the
system on which you issued the startserver command):
# cli checkrclink stopserver <N:S:P>
5. Repeat Step 2 through Step 4 on each link and each system in the configuration.
SolutionProblem
See:Link throughput and latency are unsatisfactory.
• “Increasing MTU” (page 33)
Increasing MTU
If the result of the cli checkrclink test shows a value greater than 1500 bytes for Max MTU,
you can increase the MTU size to a maximum of 9000 bytes.
Perform the following steps to increase the MTU:
Setting Up Remote Copy over IP 33