[OpenAFS] fs setserverprefs and supernetting

Assarsson, Emil Emil.Assarsson@sonyericsson.com
Tue, 2 Nov 2010 09:10:42 +0100

>-----Original Message-----
>From: Jim Rowan [mailto:jmr@computing.com]=20
>Sent: m=E5ndag den 1 november 2010 16:54
>To: Assarsson, Emil
>Cc: openafs-info@openafs.org
>Subject: Re: [OpenAFS] fs setserverprefs and supernetting
>On Nov 1, 2010, at 4:31 AM, Assarsson, Emil wrote:
>> Hi all,
>> I would just like to have your input on this method of setting =20
>> serverprefs based on the supernet distance.
>> The background is that we have a large WAN with high latencies. The =20
>> default method of calculating the weight for serverprefs is not good.
>> We could have done this with static weighting but we need to keep =20
>> things really flexible and self-configuring.
>There's a built-in assumption here that IP address assignments have a =20
>clear relationship with latency.  That's probably accurate in so far =20
>as your company uses supernetting for routing.  If you hand off Wan =20
>connections to MPLS, for instance, that might no longer be a good =20
>assumption, and this approach may fall down.  This algorithm does =20
>appear to be an improvement over the built-in one, though.

I guess that periodic latency measurements and comparisons between servers =
would be better but that is just too hard to write in perl :-P