[Mailman-Users] Moving lists to new server - question on specific files

Mark Sapiro mark at msapiro.net
Sat Jul 19 19:12:50 CEST 2014

On 07/18/2014 01:27 PM, Alfred Pope wrote:
> 1) I'm moving the lists from version 2.1.9 on Solaris 10 to version 2.1.18-1 on Ubuntu.  In an older post from Barry (which I cannot find now) he seems to indicate the list configuration files under mailman/lists/<listname>/ have not changed in these minor releases.  He didn't come right out and say it directly but that's what I got from the post.  I just wanted to clarify this.  Does the format or contents of the list config files change among these minor releases?

Yes, there are changes in the list config.pck files, mostly the addition
of new attributes, but this is not something you need to worry about
when moving a config.pck from an older to a newer MM.

Each Mailman installation has an attribute
Mailman.Version.DATA_FILE_VERSION and each list has an attribute
data_version. Every time a list is instantiated, the list's data_version
is compared to the installation's DATA_FILE_VERSION and if it is less, a
process is run which knows how to update the list to match the
installation, and the list is updated.

Thus you don't have to worry when dropping a 2.1.9 config.pck into a
2.1.18-1 installation. The config.pck will be updated as needed

There are possible issues with dropping a newer config.pck into an older
installation. In most cases this will result in 'unused' list attributes
which does no harm, but if an attribute has been renamed between the
older and newer releases, the old name will be missing in this case.
This is rare. The only recent case is from_is_list which was called
author_is_list only in 2.1.16rc2, so dropping a newer config.pck into a
2.1.16rc2 installation would be a problem.

> 2) Also concerning the files under mailman/lists/<listname>/:  several different posters say to copy over the entire contents of mailman/lists/<listname>/ but other posters say the only "necessary" files to copy are the list config.pck files.   It makes sense that if you only copy over these minimal config files, you will loose the pending requests and subscription requests for each list.  Loosing the data in pending.pck and request.pck is OK with me as long as it doesn't break the list.  The list managers will be alerted in advance to clean up their lists.  Also, the current (old) list server contains config.db files for each list in addition to the config.pck files.  This is probably due to a previous migration in 2007.  I would rather not copy everything under these list directories.  I just need the list configuration and membership data.  Is copying the minimal config files a safe plan?

Copying only the config.pck is a safe plan. The config.db files are left
over from Mailman 2.0.x and should not be copied in any case. In fact,
they should be removed from the 2.1.9 installation.

The reason for this is the data therein is very old, and it is possible
that the config.pck files could become corrupted in some way and Mailman
would fall back to the extremely outdated config.db. It's better if the
config.pck corruption is discovered soon after it occurs.

> 3) I don't plan on copying over the heldmsg and bounce files under mailman/data/  If the list managers don't clean up their lists before the move they will loose this data.  That's OK.  I just want to make sure not including those files won't break something down the road.  

That too is fine. WRT the bounce-events-ppppp.pck files, there normally
should be at most one of these (or a few if BounceRunner is sliced) with
ppppp equal to the PID of BounceRunner. If there are any with PIDs of
non-existent process, they are left behind from some anomalous event,
possibly <https://bugs.launchpad.net/mailman/+bug/1161610>.

Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan

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