Compression; Tcp Window Size/Scaling Performance Tuning - HP StorageWorks MPX200 User Manual

• Typically MTU should be set to the default of 1500; rarely do WAN networks support MTU sizes
greater than 1500.
• In addition to support for Jumbo frames, you can select other and configure the MTU size between
1000 and 9000 bytes.
• Encryption boxes on the WAN link often add a few bytes to each frame, so it may be necessary
to decrease the MTU size to 1450 to allow the encryption box add the bytes and keep the MTU
size under 1500 bytes.
• Jumbo frames can enhance the IP performance of the MPX200. Before enabling jumbo frames,
ensure that the entire network supports them.
NOTE:
Jumbo frames are not supported for use with HP Continuous Access EVA.

Compression

The MPX200 integrates a software compression option. This option can be set to disable, enable,
or auto. When set to auto, the MPX200 continually assesses data compressibility and automatically
enables or disables compression based on data compressibility. The default setting for software
compression is disable for new installations. If upgrading from an earlier version of firmware (prior
to v3.2.0.1), the existing setting is maintained (either enable or disable).
NOTE:
The auto compression mode setting is available with MPX200 firmware version 3.2.0.1 or later.
• Use the disable setting if you know that the data being transferred over FCIP is not compressible.
• Use the disable setting when using a high speed WAN link (622 Mb/s OC-12 up to 1 Gb/s)
in a configuration with simultaneous FCIP and iSCSI functions operating on the same MPX200
blade.
• Use the enable setting if you know that the data being transferred over FCIP is compressible.
• Use the auto setting if you are unsure of data compressibility.
NOTE:
All mode settings require the proper setting of the MPX200 bandwidth per route parameter,
matched to the guaranteed available bandwidth (QoS) of the WAN link, based on the number
of routes. See
setting if the available bandwidth per route is inconsistent or unpredictable.

TCP window size/scaling performance tuning

The MPX200 FCIP performance is maximized when properly configured. Knowing the RTT (distance)
between MPX200 Multifunction Routers and the WAN dedicated or guaranteed bandwidth allows
the gateways to be tuned for optimal performance. See
Bandwidth per route, page 132. HP does not recommend that you use the auto
Modifying the window size and scaling
MPX200 Multifunction Router User Guide
factor.
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