[mirror-admin] please use ASNs, delete redundant netblocks

[Chuck Anderson]

On Thu, Mar 04, 2010 at 10:43:47AM -0600, Matt Domsch wrote:
> Hi all.  For a few months now, Fedora's MirrorManager instance has had
> the ability for mirrors to specify the BGP ASN of your network, in
> addition to separately listing your netblocks.
> 
> Some sites have quite a few netblock entries, which are all covered
> now by the single ASN.  As the lookups on each client request must go
> through all of the netblock entries in the database to some extent,
> the now-redundant netblock entries only serve to slow things down,
> even if it's just a little bit.
> 
> Please review your Host entries in MirrorManager, and if you have set
> an ASN, and if your netblock lists are completely covered by your ASN
> setting, please delete your netblock entries.

I would also make sure that your ASN is actually visible to 
MirrorManager before doing that.  Especially if you are usihg IPv6 
prefixes, hierarchical summarization of IPv6 routing may hide the view 
of your ASN from the global routing table and hence MirrorManager 
might not see it.  But the same thing could happen with IPv4 if you 
are using PA address space from your ISP.  Even if you announce your 
separate prefix to a different ISP, there is no guarantee that your 
longer prefix route (and hence ASN) will be visible at the point of 
observation by MirrorManager.

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