How to fix hash sum mismatch and size mismatch errors from apt-get / apt-cacher
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BY webmaster
11 years ago
Technical-Solution
7 comments comment
We run apt-cacher to save bandwidth in our intranet. All Ubuntu systems in our office uses the apt-cacher server to update and upgrade. Recently we started getting the hash sum mismatch and size mismatch errors. After some dabbling with the settings and the files we figured out a simple solution for this problem. Whenever we were running apt-get update, apt-get upgrade or apt-get dist-upgrade we were getting these annoying show-stoppers. The exact errors we were receiving were of this form
W: Failed to fetch http://192.168.1.5:3142/ubuntu/..i386.deb Hash Sum mismatch
or 
W: Failed to fetch http://192.168.1.5:3142/ubuntu/...deb Size mismatch

Once we started getting this error for a package in one of the machines in the network, it reoccurred for the same packet on all the other machines in the network. So we figured that it had something to do with the apt-cacher and we forced a reload of the specific package by going to the apt-cacher repository(we have it at the default location - /var/cache/apt-cacher) and deleting the file with the name for which the error was triggered from within the var/cache/apt-cacher/private folder. This file is a flag which is used to indicate the download status of the specific package.

While doing research on this problem we also realized that a possible solution was to change the repository server to some other server than the one already setup, either manually by editing the sources.list file or by changing it from synaptic package manager. This was how we initially solved the problem to get going but we have a lot of systems and we had only limited bandwidth and we had to save the bandwidth.

We also realized that we started getting this problem once we setup the apt-cacher with expiry-time of 24 hours. It could possibly have been that the packages were updated in between and our cache had gotten stale. So a similar issue could happen when people use proxies or apt-on-cds for updating packages. Once we fixed the errors we set the expiry-time to 0 which meant that new packages.gz files are downloaded every time someone requested for an update/upgrade. Hope this helps.

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on 04th April 2007 / by webmaster
Linux is the epitome of the FLOSS model. Technical Solution Linux installation Leave a reply Your email address will not be published. Required fields are marked * Dewey J. Corl (not verified) access_time 10 Jul 2020 - 10:07 Linux is not ready for the general public! (I am a Ubuntu user). For proof, 1. try to simply print labels on a Dymo label printer. It takes a LOT of work to get to the ease of label printing already available in Windows and Mac. 2. try syncing a modern Palm based PDA. Yes, jpilot and others will sync the main data, but pictures and midi files do not get transferred without a lot of extra setup. These are examples of applications that are not ready for the general public. Since an operating system only supports applications, Linux is not ready to be a common desktop for the general public. While we are waiting for the applications to catch up, keep up the good work!! Anoop John (not verified) access_time 10 Jul 2020 - 10:07 Dewey Yes you may be right. But these are not applications that a common man would use. A common man would use one of these applications - Internet browser, Chat Client, Email Client, Document Writer, Presentation Creator, Spreadsheet Editor, Movie Viewer, Music Player, CD/DVD Writer. Both examples you cited are more specific applications that only a small percentage of the whole population uses. It will take time before those hardware vendors identify the need from their perspective to address the Linux community. Krishnadas (not verified) access_time 10 Jul 2020 - 10:07 Dear Mr Anoop, Thank you very much for the free installation of LINUX done in my PC. I am getting immersed in the LINUX and seeing the versatility. To my surprise, I am able to read one of my old backup CD(wherein lot of my valuable file exist) done in DIRECT CD wizard (a custom cd writing software of Easy Cd creator in WIN98) which could not be read in XP. Installation of old version of easycd creator/direct cd program was not possible in XP. I thought that possible i lost all data. Very pleasant start! Srikanth N. S. (not verified) access_time 10 Jul 2020 - 10:07 Hi Anoop, My friend is thrilled with Ubuntu. One of his grouses with windows was that after OS installation, everything else is to be installed separately which is a real headache. WHereas if u install Linux, everything is installed as a package and he is thrilled to bits! Let linux installation spread in Trivandrum and your service in this direction is highly appreciated. Kepp up the good work Regards. PDA Freak (not verified) access_time 10 Jul 2020 - 10:07 Is it possible to install linux on a packardbell notebook ? Pagination First page « First Previous page ‹ Previous Page 1 Current page 2 Page 3 Next page Next › Last page Last » Add new comment
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Hudson FAS (not verified)
access_time 10 Jul 2020 - 12:48

in /usr/share/doc/apt-cacher/README.Debian.gz, we read:

MULTIPLE REPOSITORIES:

It has been requested that apt-cacher support being used on a network that hosts both Debian and Ubuntu boxes. There are frequent namespace clashes between the 2 distributions which have files with identical names, but different contents. This problem was not envisaged in the original design of apt-cacher and is difficult to accommodate.
However, it is possible to workaround this by running a separate apt-cacher daemon for each Distribution on a different port with its own cache directory ...
...


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Anonymous (not verified)
access_time 10 Jul 2020 - 12:48

#!/bin/bash
## run on each client
apt-get clean
rm /var/lib/apt/lists/*
rm /var/lib/apt/lists/partial/*
apt-get clean
apt-get update
#EOF