[CentOS] yum vs up2date

Lance Davis lance at uklinux.net
Thu Sep 7 17:08:25 UTC 2006

On Thu, 7 Sep 2006, Les Mikesell wrote:

> I have to disagree.  Many machines here run through the same caching
> proxy and the current system rarely has a cache hit, while the
> earlier version almost always had hits after the first machine had
> done an update.  Or maybe I'm comparing the centos3 scheme to centos4.
> I don't really know what has changed, but centos4 is as bad as fedora at
> defeating what caching proxies are intended to do.  Whatever you are
> doing to choose an appropriate mirror is not at all consistent from a
> given location so every subsequent request ends up pulling from a
> different url.  If what you are doing is correct, shouldn't it be
> repeatable from the same location (i.e. through the same proxy)?

If you are using fastestmirror plugin then it should always pick the same 
mirror, although it will retes at intervals and use a faster one if it 
finds it.

Assuming the proxy works by url then that should find the requested files.

If you arent using fastestmirror then it may use a sequence of mirrors in 
the list, and the 2nd server wouldnt necessarily use the same one as the 

The best soluton for you would probably be to look at which mirrors are 
seen to be the fastest in the mirrorlist results and hard code those into 
your repos configuration for all your servers. Listing one or two should 
give you fallback.

CentOS 3 wont have the same issue because all updates are referenced via a 
round robin set of mirror.centos.org, which will always be seen as the 
same url by the proxy.

One way to do what you want would be to use round robin geoip enabled dns 
for the mirrors , but then all the mirrors would have to respond to a 
subdomain of centos.org - which probably isnt going to happen ...

>> There's some parental pride which will be resistant to change over the
>> current script, although if it's a worthwhile improvement, I'm sure
>> reason will prevail.
> Maybe those claimed 1.5 million users are really a few users or
> locations
> with a lot of machines...  Letting proxies work as designed would
> make sense to me.

Well the issue is that you want a proxy to always hit the same mirror - 
(which you can configure) whereas we want to spread the load between the 
mirrors ...


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