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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A common source of difficult-to-diagnose issues with SNFS is improper 

IP network configuration. Many incorrect IP configurations might appear 

to work when tested with particular applications or particular kinds of 

hosts, but fail when used with SNFS or when a different kind of host is 

added to the cluster.
SNFS Distributed LAN should be run over one or more dedicated IP 

subnetworks, using dedicated NICs for each subnetwork. These 

subnetworks are typically configured using site-local addresses, such as 
10.a.b.c

 or 192.168.x.y.

For example, if SNFS Distributed LAN is set up to use two Gigabit 

Ethernet NICs (for a total bandwidth of 2 Gbits/s for Distributed LAN 

I/O), each Distributed LAN Server and Distributed LAN Client should 

have at least 4 NICs: 2 dedicated NICs for Distributed LAN, 1 dedicated 

NIC for SNFS Metadata traffic, and 1 NIC for administrative access and 

other traffic. Each of the NICs must be configured for a separate IP 

subnet. So for example, if the subnets chosen for Distributed LAN are 
192.168.1.0/24

 and 192.168.2.0/24, each Distributed LAN Server and 

each Distributed LAN Client must have one (and only one) NIC with an 

IP address of 192.168.1.x, plus one (and only one) NIC with an IP 

address of 192.168.2.y.
It is best practice to have all of the NICs for the same Distributed LAN 

subnetwork directly connected to the same network switch. A router 

between a Distributed LAN client and server could be easily 

overwhelmed by the data rates required.
By contrast, Quantum recommends having the NICs for different 

Distributed LAN subnetworks connected to different network switches, to 

avoid overwhelming any one network switch. 
All Distributed LAN subnetworks must be completely connected. This 

typically means all Distributed LAN clients and all Distributed LAN 

servers have dedicated NICs for each of the Distributed LAN 

subnetworks.  If a Distributed LAN client does not have a dedicated NIC 

for a particular Distributed LAN subnetwork, it must be configured with 

static routes to give it connectivity to each of the IP addresses advertised 

by the Distributed LAN servers.  Note that if a Distributed LAN client is 

unable to connect to a particular server’s NIC, it will continue forever 

trying to connect to it, potentially causing slow file system mounts, 

repeated messages in error logs, and other problems.