IBM System Storage DS4000, Hardware Manual

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IBM Midrange System Storage Hardware Guide
If jumbo frames have been enabled and performance appears to be substantially less than
expected, disabling jumbo frames on the DS5000 storage subsystem is a simple and quick
troubleshooting step, as shown in Figure B-3. We found that, based on empirical tests of
several varieties of iSCSI HBAs, that using jumbo frames led to, on occasion, degraded
performance.
Figure B-3 Jumbo frames enabled on the iSCSI host port
Virtual Local Area Networks
Virtual Local Area Networks (VLANs) are a grouping of devices that communicate on the
same broadcast network, even though they might be physically separate. A VLAN has the
same basic characteristics of a normal LAN, but it allows for a greater degree of flexibility
within a networked infrastructure, and it allows reconfiguration using software instead of
physical movement of devices.