[OpenAFS] Why is speed of AFS loopback adapter set to 10 Mb, even if physical interface is Gb capable?

Holger Rauch holger.rauch@empic.de
Mon, 26 Apr 2010 18:32:15 +0200

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Hi Jeffrey,

thanks for your reply.

On Mon, 26 Apr 2010, Jeffrey Altman wrote:

> [...]=20
> Rx jumbograms have nothing to do with IPv6.  OpenAFS has no IPv6 support
> at present.  See "-jumbo" option on the UNIX CM

Sorry, didn't find anything about "-jumbo" in the afsd man page. So,
to which daemon does this option belong to exactly?

> and servers and the
> equivalent registry value for Windows that is documented in Appendix A
> of the OpenAFS for Windows Release Notes.

Yes, I read the appendix. I came accross a registry parameter having
"NoJumbo" in it. So, I suppose I've got to set the value for that
parameter to 0 in order to enable jumbogram usage on Windows, right?

> >> [...]
> >> On Windows, there is one type of cache.  It is a memory mapped paging =

Ok, and how should it be tuned for a gigabit networking environment?
(Please see my notes below).

> >=20
> > Ok, how do I tune that appropriately?
> All of the knobs are described in the OpenAFS for Windows Release Notes.
>  If you have not read them, please do.  If you then have questions, feel
> free to ask them.

Well, "described" is a bit exaggerated, IMHO. They are "mentioned" in
the sense that a short statement is made as to what each parameter is
determined for. There's nothing wrong with that, but what's missing
IMHO are explanations as to how the parameters are related to each
other, especially in the sense of performance tuning. Furthermore,
concrete examples for *current* network setups (e.g. gigabit
networking) would be nice.

So, as unfortunate as it may be, I have to repeat my original
question, slightly paraphrased in two questions:

Which parameters should be adjusted for an OpenAFS Windows client
and a Unix server when both are operated in a gigabit network? What
values are recommended for these parameters?

(Sorry to bother you with these questions, but IMHO sort of hard to
infer from the release notes without concrete examples).

Thanks for your advice & kind regards,

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