McDATA Eclipse 2640 SAN, Administration And Configuration Manual

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6
Monitoring SAN Router Operation and Connections
6-35
Viewing Statistics
Table 6-13 Remote Connection Statistics Report
Item Meaning
Transmit Traffic The average data rate sent to the remote SAN Router over the
previous polling interval, in megabytes per seconds.
Receive Traffic The average data rate received from the remote SAN Router
over the previous polling interval, in megabytes per seconds.
Latency The time in milliseconds required for the most recent keep-alive
message to travel round-trip from the local to the remote SAN
Router and back. Keep-alive messages are sent at an interval
equal to 1/3 of the connection timeout value. Thus if the
connection has a timeout value of 30 seconds (the default), the
latency measurement is updated every 10 seconds.
Retransmitted Segments The count of segments that had to be re-transmitted to the
remote SAN Router during the last polling interval. A large
number of re-transmitted segments indicates an unreliable WAN
connection, resulting in poor throughput.
TCP Slow Starts The count of congestion events on all TCP sessions within the
iFCP connection. A congestion event is either a Slow Start
(typically initiated by a timeout), or a Fast Recovery action
(typically initiated by duplicate ACKs indicating a lost packet).
Dropped Connections The number of times the connection to the remote SAN Router
was lost during the last polling interval. This count represents
failures in the WAN link that interrupted traffic to the remote SAN
Router. The Dropped Connections count is cumulative but can
be reset to zero via the
Reset button. Resetting this counter
does not change the counter in the SAN Router hardware.
Resetting saves a baseline value and displays the difference
between the current value and the saved baseline value.
Closing and re-opening the
Remote Connection Statistics report
displays the cumulative total again. Reset also discards the
graph data, so the graphs begin to display again.
Sessions The number of initiator-target pairs (host-disk pairs) currently
active to the remote SAN Router. For example, if three servers
in the local mSAN each have four disks mounted from the
remote SAN, there would be twelve sessions. This is also the
current number of parallel TCP connections making up the
logical remote SAN Router connection.
Traffic Selecting this option presents the remote connections statistics
for the traffic graphs (xmt and rcv traffic)
Other Selecting this option presents the remote connections statistics
for the other graphs (latency, retransmitted segments, and slow
starts)