Comment 27 for bug 1626436

So, as another datapoint, I have built the same package with sbuild on 4.4 and 4.8.

I grabbed 4.4 from xenial, rebooted into it. built the same trival package that i built yesterday on 4.8
$ ( cd /home/smoser/ubuntu/logs/ && grep "^Build needed" smello_0.4~ppa1_amd64-2016-10-2*)
smello_0.4~ppa1_amd64-2016-10-20T16:48:33Z.build:Build needed 00:02:34, 120k disc space
smello_0.4~ppa1_amd64-2016-10-21T18:31:17Z.build:Build needed 00:00:32, 120k disc space

So the difference there is that it took 32 seconds to build the package on 4.4 and 154 seconds on 4.8. I've not done any more investigation as to what all is slow, load does show high on 4.8 when doing an sbuid, and this isn't a matter of a download taking longer.