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Revision as of 18:11, 31 January 2011 by Mdomsch (talk | contribs) (Optimizing for an edge case?)

I see that the on-board NICs are enumerated 1, 2, 3, & 4. What does this mean for motherboards that have more than 4 NICs? We use ATCA boards that consistently have 6 to 8 on-board NICs. How would these be enumerated under the new system?

2011-01-31 mdomsch: There is no limit to the number of on-board NICs. I used the example of 4, but if you have more, say N, and SMBIOS or PIRQ reports those all as on-board, they will be named em1..emN.

Avoiding this feature

Will there be any way to disable this feature on fresh install? (e.g. removing udev-script or disabling it in script in /etc/sysconf). I want to keep with Linux interface naming standards based on protocol (eth, ppp, tun, tap) and not with half-half mess made by this feature. Thank you for reply.

2011-01-28 Yes, we are adding a kernel command line option to disable biosdevname from running at install time; you can also uninstall the biosdevname package after install. -mdomsch

Avoiding it at all!

This new feature can introduce much more problems then it solves. Looks scary for me as sysadmin and programmer. Well, a lot of net scripts, iptables rules and other stuff involved. Yes, I use variables in bash, and other tricks that will help me to survive such global change. But the question is simple: Is a such little benefit worth of such huge bunch of stupid work for all Fedora users?

Optimizing for an edge case?

It seems to me this is simply optimizing for an edge case instead of the general use.

Frankly using mii-tool seems much more reliable and easier to identify the Nics. and then just label them in the ifcfg-* files. And what's to say that Motherboards are going to consistently have their ports named and numbered in a consistent order either? the udev changes with the 70-persistent-net* file seems to have made nic handling on linux SOO much better when adding multiple nics in a system. Especially since once you find out which nic is which you can just edit the file and name them where you want and reboot. --Urkle 21:34, 26 January 2011 (UTC)

2011-01-31: Yes, you can always do this, both with and without biosdevname. Good luck doing it for more than a few servers.

Virtual Function Devices?

Newer server NICs often have a feature called Virtual Functions. This is a virtual NIC bridged to a real NIC port. The virtual function can then be assigned to a virtual machine using Vt-d. This avoids the need for context switches during send/receive and increases network speed for virtual machines.

How will the virtual functions be called (on the host, while the vm is not active)?

Will they get a constant name, even if their MACs are random?

I ask this because the naming of vfs was a big mess when vfs were first introduced. --Gvegidy 21:41, 26 January 2011 (UTC)

2011-01-28: Yes, virtual functions (VFs) on SR-IOV devices will have a suffix of "_<number>" appended to their name. For example, pci2#1_63 is the card in PCI slot 2, port 1, VF 63. These are exposed in the Host, and may then be direct-assigned to a Guest (using VT-d). The MACs are random, but the naming convention will remain. --Mdomsch 28 January 2011

Benefit for ordinary user

I see benefits for this only in special configurations, like servers with big number of network cards, or stateless, or PXE boot, or cluster, etc. For ordinary users it brings only subtle benefits and much more inconvenience. May be this feature shouldn't be enabled by default?

2011-01-31 mdomsch: "ordinary users" (e.g. Desktop users?) are presumably using NetworkManager, which doesn't care what the device name actually is, it finds devices and uses them. I also disagree about "much more inconvenience". Please elaborate.

Well, ok, this feature is not concern those who are using only NetworkManager and nothing more. But, quite big portion of people in Fedora are experimenting or just going to get some experience. This feature, IMHO, will make learning threshold higher for them as it will invalidate many of manuals found in the Internet for networking things. For example, creating virtual machines in libvirt with bridging (NM still doesn't support this, AFAIK), firewalling/traffic control/routing, or just binding network daemon to specific interface, etc. For admins and people who help on chats or forums this is also true, but they have enough experience to grasp what is going on. --Atorkhov 15:51, 31 January 2011 (UTC)