Posts Tagged ‘nic’

Linux and Active State Power Management

Last year I had an odd issue when installing CentOS 6.0 on a Supermicro motherboard with an Intel PCIe quad port GB nic using an 82576 chip. I got by the initial kernel panic by using pci=noaer as a kernel option but later encountered really weird kernel panics regarding the Intel nic again which required an additional pcie_aspm=off in my grub file. Pretty odd stuff really since this was a server and I wasn’t worried about managing my power consumption since we’re a small company and I simply want the server to stay on. There’s a number of good articles about ASPM & Linux over on the website which I found very interesting.

Initial bug report from RHEL:

A number of Kernel parameters one can use at boot time to help troubleshoot things:

Initial Phoronix News article that got me wondering if Linux’s implementation of ASPM might be my problem:

I can see how ASPM would be really important to laptop users sure, but when I’m installing a server I don’t need stuff shutting down on me when not in use. (Of course this is different for datacenters!)


Linux bonding: How to maximize your throughput by combining nics.

I’m currently working on building my own iSCSI SAN w/ SCST & a modified Linux kernel. Things are going pretty well but I needed to also bond out the 5 Gb nics so my VMHosts can maximize their connections. In Linux, you bond out an interface by creating a new network interface and telling the physical nics to register w/ that virtual network interface. There’s also 7 different types of bonding modes but the most common one is mode 6 or balance-ALB (active load balancing.)

If you’re using CentOS or RHEL like I am you cd to /etc/sysconfig/network-scripts/ and vi ifcfg-bond0.

Once you’ve got vi open, you dump the following in (this is an example only. Please change your IPADDR, NETMASK and NETWORK parameters as needed.)


From there, you then modify your individual eth# interface config files so they point to the bonded device. As an example, here’s my /etc/sysconfig/network-scripts/ifcfg-eth0 interface file.


And oh ya, don’t forget to modify your modprobe.conf file to specify the loading of the bond kernel module and what options it will needed @ run-time.

alias bond0 bonding 
options bond0 mode=6 miimon=100

Couple of useful links. There’s tons of good info on bonding w/ Linux. Keep in mind, some distros don’t want you to modify the individual interface config files so use their administrator control panel first if possible.

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