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Checking the SNC Ethernet Ports
1
Verify that the data ports are set to auto negotiate or forced to 1000 Mbs. The CLI command get
ethernetspeed all shows the current speed.
Refer to
Configuring the Ethernet Port
2
Verify that the MTU size is set to optimal setting for the LAN/WAN environment.
Refer to
Configuring the Ethernet Port
the SNC. Smaller frame sizes causes a decrease in performance.
3
Verify that the SNC TraceLog feature is disabled. Tracelog tracks certain events that occur in the SNC.
With this log enabled, performance suffers.
Refer to
Diagnostic Commands
Checking the LAN/WAN
1
Verify that the MTU size is set to optimal setting for the LAN/WAN environment. Refer to
[port number] [MTU choices]
9k frame size is the current optimized frame size for the SNC. Smaller frame sizes causes a decrease
in performance. Many switch and router vendors do not support the larger frame size of 9k or 16k. Refer
to
Performance Issues
2
Verify that each associated port in the IP SAN is configured for 1000Mbs.
IP SAN traffic should be segmented so that it does not interfere with the main LAN network traffic.For
better performance, the IP SAN should be on its own set of hardware.
3
Verify that packets are not being dropped along the LAN/WAN. Many utilities track packet activity and
switch statistics.
Checking the Ethernet Host Adapter or NIC
Ethernet Storage Adapters generally outperform accelerated NICs and un-accelerated NICs by offloading
most of the processing from the host.
An accelerated NIC provides some offloading, but still requires a host OS iSCSI driver, making the host
spend more CPU cycles.
An un-accelerated NIC does not offload anything so the CPU must do much of the processing.
To check the Ethernet host adapter or NIC
1
Verify that the adapter or NIC is sent to auto-negotiate or forced to 1000 Mbs.
2
Set the MTU size to the largest MTU size supported in the LAN/WAN. Refer to
number] [MTU choices]
9k frame size is the current optimized frame size for the SNC. Smaller frame sizes causes a decrease
in performance. Many switch and router vendors do not support the larger frame size of 9k or 16k. Refer
to
Performance Issues
3
Set the maximum transfer size to the most efficient size for the intended target(s). For many tape drives,
64k is the optimal setting.
Checking the Applications
Some applications can be configured to change transfer sizes. Configure the application for the optimal size
for the particular SCSI device(s) connected to the SNC.
SNC 450x User's Guide
on page 37.
on page 37. 9k frame size is the current optimized frame size for
on page 53.
on page 86.
on page 48.
on page 86.
on page 48.
set DPMTU
set DPMTU [port
49
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