Comment 15 for bug 1471903

Did you mean a vivid chroot with -updates, -security and -proposed? Regardless, should -proposed be included as those packages wouldn't be installed on the devices. Additionally, did your sources.list file also include deb-src lines? Removing that would reduce the size of the files in /var/lib/apt/lists. Finally, don't we want to look at the difference between the existing size of /var/lib/apt/lists/ and one which contains -updates and -security? Doing that in a vivid chroot, although on amd64, I see the following:

(vivid-amd64)root@impulse:/home/bdmurray# ls -lh lists-no-updates-security.tar.gz
-rw-r--r-- 1 root root 17M Aug 17 13:37 lists-no-updates-security.tar.gz
(vivid-amd64)root@impulse:/home/bdmurray# ls -lh lists-with-updates-security.tar.gz
-rw-r--r-- 1 root root 18M Aug 17 13:36 lists-with-updates-security.tar.gz

That is only a difference of 1M unless I'm missing something.