[mirror-admin] Mirror server bandwidth query

[Matt Domsch]

On Mon, Apr 13, 2009 at 02:14:18PM -0500, Chris Adams wrote:
> I've noticed that my mirroring from download3.fedora.redhat.com seems to
> have slowed down.  I used to mirror from download2, and I got good
> download speeds, but now I'm usually only seeing about 5-7 Mbps from
> download3.
> 
> For comparison, I was downloading a RHEL DVD image from RHN, and I got
> 62 Mbps (with peaks to 80 Mbps).  A TCP traceroute shows both taking the
> same path to Phoenix.  I would expect that Red Hat reserves bandwidth
> for paying customers (and I appreciate it every time I need an ISO!),
> but there obviously doesn't appear to be any bandwidth issue along the
> path.
> 
> Anyway, just curious.  I hadn't really given it a lot of thought until I
> noticed my RHN download went significantly faster.


download2 is defunct, no ETA on its replacement.  It has thus far been
a casualty of Red Hat's move out of the Tampa data center into a
second data center in Phoenix.  Some of your speed seen with download2
may have been because it was being served from a different data
center, thus different path to you.

download3 in Phoenix is taking the brunt of the load, as that's the
name most folks know, and download1 is a CNAME to download3 right now.
download4 and download5 are also in the same data center in Phoenix;
you might have better luck with them.  However, I suspect that all
three servers share the same back-end storage, which if it's overloaded
you won't get good speeds from any of them.

I'm fairly certain that the "null rsyncs" are a big part of the
problem of perceived speed.  If we could eliminate most of those,
either via the rsyncFilter or fullfilelist or more consistent
scheduling of new content, I think the download experience will
improve for everyone.

I also strongly encourage non-Tier-1 mirrors to pull from a Tier 1
mirror instead of download*.  As a reminder of [1], the Tier 1's you
can use are:

mirrors.{us,se,nl}.kernel.org 
wpi.edu
rsync.hrz.tu-chemnitz.de
fedora-rsync.ftp.pub.2iij.net
sunsite.mff.cuni.cz
ftp.heanet.ie
mirror.speedpartner.de
fedora.c3sl.ufpr.br

All of these mirrors are on Internet2 or similar (except
mirrors.us.kernel.org), have a gigabit network connection, and are
full mirrors which sync often.


[1] https://fedoraproject.org/wiki/Infrastructure/Mirroring/Tiering

Thanks,
Matt
Fedora Mirror Wrangler

-- 
Matt Domsch
Linux Technology Strategist, Dell Office of the CTO
linux.dell.com & www.dell.com/linux

--