Still celebrating National IT Professionals Day with 3 months of free Premium Membership. Use Code ITDAY17


Load balancing across dual NICs

Posted on 2000-03-09
Medium Priority
Last Modified: 2010-03-18
I've got an NFS server exporting a couple filesystems to approximately 120 servers. These are all on the same class C, connected to a Cicso Catalyst 5513, and spread fairly evenly across the two halves of the backplane on the Catalyst.

I've got both NICs up and running currently, with a round-robin DNS entry, but the vast majority of the traffic is still hitting eth0. I'm afraid it's due to eth0 being the default gateway.

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface *      UH    0      0        0 eth0 *      UH    0      0        0 eth1   *        U     0      0        0 eth0   *        U     0      0        0 eth1       *            U     0      0        0 lo
default         gateway         UG    0      0        0 eth0

Essentially, what I'm looking for is a way to aggregate the two 100Mbs connections.

All servers are running RH 6.0 with 2.2.14 and all current patches.
Question by:mwallis
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
LVL 40

Expert Comment

ID: 2602126
I believe the only way you'll load balance across both NIC's will be to split the class C into two subnets with half the clients on each. The only other way would be if you could find a software package for 6.0 that implements 802.3 trunking and NIC bonding.

The system sees both NIC's on the same network. While it will accept requests on both NIC's, I think it's sending all the return data out of the first NIC that it finds connected to that network (eth0).

Author Comment

ID: 2602276
I was afraid of that, but I'm really trying to avoid ripping the kernel to pieces to implement channel bonding a' la Beowulf style.

I've read somewhere that spoofing the MAC and assigning both cards the same ip might have the desired effect, but I havn't had the opportunity to test it.

Anyone else have any suggestions?

Expert Comment

ID: 2605195
What NICs you have?

Author Comment

ID: 2605536
eth0: 3Com 3c905B Cyclone 100baseTx at 0xe800,  00:50:da:70:04:22, IRQ 5
  8K byte-wide RAM 5:3 Rx:Tx split, autoselect/Autonegotiate interface.
  MII transceiver found at address 24, status 7849.
  MII transceiver found at address 0, status 7849.
  Enabling bus-master transmits and whole-frame receives.
eth1: 3Com 3c905B Cyclone 100baseTx at 0xec00,  00:50:da:16:f0:a7, IRQ 10
  8K byte-wide RAM 5:3 Rx:Tx split, autoselect/Autonegotiate interface.
  MII transceiver found at address 24, status 7849.
  MII transceiver found at address 0, status 7849.

Accepted Solution

pheur earned 450 total points
ID: 2707441
What you can do is to recompile the kernel with the following options:
- advanced router
- equal cost multipath
In this case you will have the two NICs (you may use the same IP and netmaskon both of them), the kernel will have two routes to the local network, one through each eth and comforming to the kernel documentation will choose undeterministically one of them.

Featured Post

Free Tool: ZipGrep

ZipGrep is a utility that can list and search zip (.war, .ear, .jar, etc) archives for text patterns, without the need to extract the archive's contents.

One of a set of tools we're offering as a way to say thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

I have seen several blogs and forum entries elsewhere state that because NTFS volumes do not support linux ownership or permissions, they cannot be used for anonymous ftp upload through the vsftpd program.   IT can be done and here's how to get i…
Note: for this to work properly you need to use a Cross-Over network cable. 1. Connect both servers S1 and S2 on the second network slots respectively. Note that you can use the 1st slots but usually these would be occupied by the Service Provide…
If you're a developer or IT admin, you’re probably tasked with managing multiple websites, servers, applications, and levels of security on a daily basis. While this can be extremely time consuming, it can also be frustrating when systems aren't wor…
In this video, Percona Director of Solution Engineering Jon Tobin discusses the function and features of Percona Server for MongoDB. How Percona can help Percona can help you determine if Percona Server for MongoDB is the right solution for …

688 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question