Quantum 6-01376-05 User Manual

  StorNext File System Tuning

The Distributed LAN (Disk Proxy) Networks

StorNext File System Tuning Guide

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The SNFS External API might be useful in some scenarios because it 

offers programmatic use of special SNFS performance capabilities such as 

affinities, preallocation, and quality of service. For more information, see 

the

chapter of the 

The Distributed LAN (Disk Proxy) Networks

As with any client/server protocol, SNFS Distributed LAN performance 

is subject to the limitations of the underlying network. Therefore, it is 

strongly recommended that you use dedicated networks for Distributed 

LAN traffic, to avoid contention with other network traffic. Gigabit 

(1000BaseT) Ethernet is recommended. Neither TCP offload nor jumbo 

frames are required.

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Dedicated networks can help provide the most predictable, deterministic 

level of performance. However, if shared network service is required 

(perhaps for peak NIC bandwidth utilization,) network contention could 

result. Network contention can lead to poor or inconsistent Distributed 

LAN performance, poor or inconsistent performance of other distributed 

applications, and, depending on their resiliency, intermittent failures of 

those applications.
SNFS Distributed LAN can easily fill several Gigabit Ethernets with data, 

so take special care when selecting and configuring the switches used to 

interconnect SNFS Distributed LAN clients and servers. Ensure that your 

network switches have enough internal bandwidth to handle all of the 

anticipated traffic between all Distributed LAN clients and servers 

connected to them.
A network switch that is dropping packets will cause TCP 

retransmissions. This can be easily observed on both Linux and Windows 

platforms by using the netstat -s command while proxy I/O is in 

progress.
Reducing the TCP window size used by Distributed LAN might also help 

with an oversubscribed network switch. The Windows client Disk Proxy 

tab and the Linux dpserver file contain the tuning parameter for the TCP 

window size. Note that Distributed LAN server remounts are required 

after changing this parameter.