Package: apt Version: 0.5.3 Severity: wishlist File: /usr/bin/apt-get I am maintaining a group of 50+ machines running Debian. These are a mixture of stable, unstable, and testing machines distributed geographically in three countries. All have a local caching HTTP proxy on their LANs, and they are configured to use it.
At regular intervals 'apt-get update; apt-get -ufy dist-upgrade' is run on these machines almost simultaneously (it is actually manually started by local support personnel, who for various unfortunate reasons do it during the same hour each day). This has a nasty side-effect: there may be many machines attempting to download all of the same packages in the same order through the same proxy if there is a large number of packages upgraded that day. The HTTP caches can't have a cache hit on a package until that package is fully downloaded, so ultimately many machines will end up downloading the same package at the same time through the same HTTP proxy and Internet feed. Using rsync to create a local copy of debian.org uses much more bandwidth than 50 machines simultaneously downloading new libc6 packages, so the HTTP cache strategy seems to be more efficient even if it wastes 70% of its bandwidth in the process. It would be nice if apt-get could randomize the order in which it attempts to fetch packages (and package lists files, for that matter) from any given source. In the absence of a scheme to schedule network traffic synchronously among many machines running apt-get simultaneously, randomizing the download order within apt-get would maximize the probability that any two machines are fetching different packages at any given time. This in turn improves the cache hit rate when different machines fetch the same package, as the first such machine will have had sufficient time to download the package before the second and subsequent machines make their requests from the cache. -- System Information Debian Release: testing/unstable Architecture: i386 Kernel: Linux genki 2.2.19-zb-586-smp #1 SMP Wed Mar 28 00:02:08 EST 2001 i686 Locale: LANG=C, LC_CTYPE=C Versions of packages apt depends on: ii libc6 2.2.4-1 GNU C Library: Shared libraries an ii libstdc++2.10-glibc2.2 1:2.95.4-0.010810 The GNU stdc++ library
