download very slow

Status changed to 'Confirmed' because the bug affects multiple users.

First off, is this still a problem? What mirror are you using, how fast is the download speed if you bypass acng?

We have stopped using apt-cacher-ng and are back to squid for caching.

Download speed without acng is nearly line speed.

OK, thanks for reporting back. With the option of further triage closed off, I'll close this ticket.

Anybody else running into this problem would best be served to open a ticket of their own and give us much details as possible.

Hi,

I've got a 12.04.2 box that's running apt-cacher-ng, and it's extremely, painfully slow. We have a mirror that's located in another colo; this serves as a caching instance for our distribution mirror.

It's apparent, based on testing, that the total network usage of the acng instance increases as a roughly linear function of how many connected apt-get clients there are.

1 connected client is pulling roughly 200kBps from our mirror. 10 connected clients is roughly 1.2Mbps downloading from the mirror.

Anybody else running into this problem would best be served to open a ticket of their own and give us much details as possible.

JFTR, I cannot confirm this here. I regularly see download speeds reported at 4 Mbit/s when served from the cache.

A couple of days ago I have seen a similar problem with Debian Unstable's apt. It reported "Downloading... 50kb/s" (on a 100mbit link). I watched the network, apt-cacher-ng was done transferring the file and apt's http client was also finished. But the stupid thing still reported slow data transfer, and a look with strace revealed just periodic FUTEX_WAITs but otherwise nothing suspicious.

So, honestly, if ever see such thing happening again, please watch which processes are really active and which ones do show you the numbers, then question the numbers please.

The problem does not exist when packages are served from the cache.

The problem ist when the package to be installed is not in the cache of apt-cacher-ng and needs to be downloaded. This is very slow and way below the possible speed of the Internet connection. When not using apt-cacher-ng in such situations the download speed is as expected.

Hallo,
* Robert Sander [Thu, Mar 27 2014, 08:53:33AM]:
> The problem does not exist when packages are served from the cache.
>
> The problem ist when the package to be installed is not in the cache of
> apt-cacher-ng and needs to be downloaded. This is very slow and way
> below the possible speed of the Internet connection. When not using apt-
> cacher-ng in such situations the download speed is as expected.

Ok... could you attach strace ("strace -f -o /tmp/logfile -p $(pidof
apt-cacher-ng)" as root) to show at least a little bit what's happening
under the hood?

MfG,
Eduard.

--
<Getty> LOL die Telefonnummer vom Arbeitsamt Mönchengladbach ist echt 404-0?
<Getty> Soll das nen schlechter Scherz sein?

FWIW, I did just experience such a slow download. The local network should be fast, I tried different mirrors but would usually see download speeds of only a few tens of KB/sec. I attach the requested logfile I had left running for about a minute and I hope it contains some useful information.

acng is version 0.7.26-1 from trusty

Things are in the range of 5-8Mbit/s now without any change in configuration so it might be that earlier it was simply the wifi being very busy. Most people have left the office now so things have quieted down.

Status changed to 'Confirmed' because the bug affects multiple users.

This bug is still present, apt-get update is painfully slow. Moreover, I'm trying to do-release-upgrade a couple of ubuntu machines and the initial get of package lists is going on forever, literally. I really don't understand how this can happen, this makes this tool totally useless. I'll have to revert back to apt-cacher.

Hi.

Is just the 'apt-get update' slow, or is getting the packages slow too?

apt-cacher-ng won't cache index files, so each time you do 'apt-get update' it will actually connect to upstream to see what has changed there.

I am seeing this on a box running 14.04 (acng 0.7.26-1ubuntu0.1) - nothing leapt out when I strace'd, I will try again and save to file. I am also not sure that strace-ing didn't "unstick" the acng process, which would be very odd ..

I will also try backporting a more recent acng and see if problem still exists,

I'm running an Ubuntu 14.04 and Ubuntu 16.04.5 serving the DEB cache with apt-cacher-ng.

The download of files to the older (and tested in other distros debian based) is very slow (10 to 50 kbps)

Attached are the strace files.