[lug] apt-get dist-upgrade errors

[Daniel Webb]

On Tue, Jan 09, 2007 at 12:08:19AM -0700, Sean Reifschneider wrote:

> In our case, I think our mirror has been "up" and stable for the vast
> majority of the last several years.  However, that doesn't mean that you'll
> always have bandwidth available to reach it.  In the case of our mirror,
> available bandwidth is much more of an issue than networking or system
> problems I'd guess.
> 
> The reason I say this is because we dedicate only 1.5mbps guaranteed of
> bandwidth to mirrors.  We scale it based on other bandwidth usage at our
> facility up to around 10mbps (soon, possibly up to nearly 30mbps).
> However, if a bunch of people are hitting it at the same time as one of our
> customers is copying data at 70mbps, mirrors traffic may be scrunched way
> back down to 1.5mbps.  Which could appear to some users as hanging or at
> least very slow connectivity, I'd guess.

That is what I've always assumed is happening.  I'm assuming the problem is
that apt will just sit and wait for that connection to start when the packet
has been dropped.  I haven't tested this with tcpdump to see though.
 
> This is one place where yum really wins.  It will detect that a mirror is
> hung and switch.  If you aren't happy with that, hit Control-C once and it
> will kill the current copy and switch to another source.

That's a big feature, apt should do this!
 
> I wouldn't say that apt hangs a lot.  Not for me.  I wonder if it's
> something more at your end of the network than at the mirror sites?  I
> can't remember the last time apt hung on me.  Admittedly, a lot of Debian
> systems I install software on are at our facility and we offer gigabit
> unmetered access to mirrors.  However, plenty of servers I run are not,

I've seen this on three completely independent networks over a period of
several years, on different mirrors and on machines that were set up
independently.  Either I just have really bad luck or there's a lack of
robustness with apt.  It happened several times in Arkansas over Christmas
break when I was upgrading my mom's system, and several times in the weeks
before that here in Colorado when I was upgrading my systems.  These hangs
were with Etch, which has improved in several ways (like signatures and
package list diffs) but apparently still has this problem.