Ip Performance Tuning; Distance; Bandwidth; Latency - HP StorageWorks 6100 - Enterprise Virtual Array User Manual

IP performance tuning

The MPX200 supports Fibre Channel service at transmission rates of 1 Gb/s or 2 Gb/s with a
maximum frame size of 2,148 bytes. It supports Ethernet service at transmission rates of 1,000 or
100 Mb/s with an MTU size between 1,000 and 9,000 bytes (jumbo frames). Related performance
characteristics include the following:
•

Distance

•

Bandwidth

•

Latency

•

MTU/Jumbo frames

• Compression
• TCP window size/ scaling performance tuning
Distance
Consider the physical distance between the MPX200 Multifunction Routers. This is usually measured
in RTT. The RTT can be anywhere from less than 1 millisecond to as great as 200 milliseconds.
Bandwidth
Bandwidth is a measure of the volume of data that can be transmitted at a given transmission rate.
WAN data rates range from 1.5 Mb/s (T1) to greater than 600 Mb/s (OC-12).
The bandwidth setting for the FCIP route must be set to the "guaranteed bandwidth" of the link,
regardless of the physical speed of the link. For example, if the link is 45 Mb/s, and 15 Mb/s is
allocated to network traffic, the remaining 30 Mb/s is available for FCIP. This leaves 15 Mb/s for
each of the two FCIP routes, in a configuration.
HP StorageWorks Continuous Access EVA replication solution requires dedicated bandwidth for the
intersite link. If other applications share the intersite link, some method of QOS must be used to ensure
that the replication application has uncontested access to the allocated bandwidth.
Setting the bandwidth setting higher than the available bandwidth will result in a decrease in
performance; the optimal setting matches the bandwidth setting to the available bandwidth.
Latency
Latency is the amount of time a packet takes to traverse the network from source to destination.
MTU/Jumbo frames
For MTU size there are 3 choices, normal (1500 bytes), Jumbo (9000 bytes) and other, where you
are then prompted for a value between 1000 & 9000.
Jumbo frames can enhance the IP performance of the MPX200. Before enabling jumbo frames, ensure
that the entire network supports them.
In addition to support for Jumbo frames, you can select other and configure the MTU size between
1000 and 9000 bytes.
Typically MTU should be set to the default of 1500; rarely do WAN networks support MTU sizes
greater than 1500.
MPX200 Multifunction Router 115