This documentation is for Dovecot v2.x, see wiki1 for v1.x documentation.
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If you want a transparent migration, the biggest problem is preserving message UIDs. See [[Migration]] for the problems this may cause. If you do the conversion with dsync, it preserves the UIDs.
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== Converting from MBX to MBOX ==
If you are using UW-IMAP and using the MBX format, you will need to convert it to MBOX format. The conversion process isn't pretty, but here is a script that works. You will need to get and compile the mailutil program from the UW-IMAP web site.
== dsync ==
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'''WARNING:''' Script versions listed here before 2006-05-18 11:40 UTC converted into mbx rather than mbox format, i. e. older versions did the opposite of what they were supposed to do. Use the version below: With dsync you can convert between any two mailbox formats that Dovecot supports. As much of the mailbox state is preserved as possible. Typically it's everything. See [[Tools/Dsync]] for full documentation, here are only a couple of examples:

 * mbox -> maildir migration. Set {{{mail_location=maildir:~/Maildir}}} and run {{{dsync -u username mirror mbox:~/mail:INBOX=/var/mail/username}}}
 * maildir -> mdbox migration. Set {{{mail_location=mdbox:~/mdbox}}} and run {{{dsync -u username mirror maildir:~/Maildir}}}
 * maildir -> sdbox migration. Set {{{mail_location=sdbox:~/sdbox}}} and run {{{dsync -u username mirror maildir:~/Maildir}}}

If you can successfully use dsync, you can skip the rest of this page.

== Converting from mbox to Maildir ==
 * [[http://dovecot.org/tools/mb2md.pl|mb2md.pl with Dovecot modifications]] can convert mails, preserving UIDs and keywords.
  * See also [[attachment:migrateuser.sh|script to drive the full migration for a user]].
   * This script requires patched {{{mailutil}}} that supports Maildir. One working {{{mailutil}}} binary is [[http://dag.wieers.com/rpm/packages/pine/pine-4.64-3.el4.rf.i386.rpm|RHEL4 PINE RPM]] from the [[http://dag.wieers.com/rpm/|DAG RPM Repository]]. You could also patch any version of pine/c-client and patch it with the Maildir patches from http://staff.washington.edu/chappa/pine/info/maildir.html.
 * [[http://dovecot.org/list/dovecot/2008-March/029736.html|mb2md.py]] can convert also message UIDs.
 * Yet another way to fix the UIDL migration problem. If you can generate an uildlist ("messagenumber uidl" pairs), use my new -U uidllist option to inject X-UILD: headers in the converted Maildir-file. The modified mb2md script is avalable here: [[http://www.chaos.dk/~sch/mb2md.xuidl/mb2md.xuidl.pl.gz|mb2md.xuidl.pl.gz]]. I used this to convert a cucipop installation to dovecot. pop3_reuse_xuidl=yes will do the rest. ''-- SoerenSchroeder 2009-02-13''

Check also the '''User-Contributed Maildir Support''' section [[http://www.qmail.org/top.html#usersoft|on the qmail community site]] for more choices.

Example (user's mail in {{{~someuser/mail}}} and INBOX in {{{/var/mail/someuser}}}):
Line 9: Line 26:
cd ~someuser
mb2md-3.20.pl -s mail -R
mb2md-3.20.pl -m -s /var/mail/someuser
mv mail mail.old
}}}
Now the mail will be in {{{~someuser/Maildir}}}. Do not forget to migrate the subscriptions as well, otherwise the new maildir will seem to have only an inbox when viewed through a mail client that supports them. This can be as simple as copying the old {{{~someuser/mail/.subscriptions}}} file to {{{~someuser/Maildir/subscriptions}}} (warning: I have not tested this extensively, my subscription list and folder hierarchy was very simplistic).

== Hierarchy separator change ==
The default hierarchy separator with Maildir is '.' instead of '/' which is common with mboxes. To keep the migration transparent to users, you can keep the '/' separator by using [[Namespaces|namespaces]]. In any case you need to replace the '/' with '.' in the subscriptions file:

 . {{{
sed 's:/:.:g' subscriptions > subscriptions.new
mv subscriptions.new subscriptions
}}}

UW-IMAP's subscriptions file is in {{{~/.mailboxlist}}}. Dovecot's mbox subscriptions is in {{{<mbox root dir>/.subscriptions}}}. Dovecot's Maildir subscriptions is in {{{<maildir root>/subscriptions}}}.

Also if you're migrating from UW-IMAP, you probably had "mail/" prefixes in the mailbox names. You can again use [[Namespaces|namespaces]] to let clients use the prefix, or you can tell your users to remove the namespace prefix from their clients and change the subscriptions file:

{{{
sed 's/^mail\.//' subscriptions > subscriptions.new
mv subscriptions.new subscriptions
}}}
Note that because Maildir uses '.' as the hierarchy separator in filesystem, it's not possible to have mailbox names containing '.' characters, even if you changed the separator in namespaces. If you really want to have dots, the only way to do this is by modifying the filesystem separator in {{{MAILDIR_FS_SEP}}} and {{{MAILDIR_FS_SEP_S}}} defines in {{{src/lib-storage/index/maildir/maildir-storage.h}}} file in the sources. Do not be tempted to change {{{MAILDIR_FS_SEP}}} et al to '/'; it won't work.

== Converting from Maildir to mbox ==
This is especially helpful if you want to archive your mail to a single file for storage on a CD, a PC, etc. But it can also be helpful if you want to use [[MailboxFormat/mbox|mbox]] with Dovecot.

Use the reformail program that comes with [[http://www.courier-mta.org/maildrop/|maildrop]]. You can also use the formail program that comes with [[http://www.procmail.org/|procmail]]. Here is a simple script showing how this works.

To use it, adjust the script to invoke the right command according to your system.

Then {{{cd}}} to the user's home directory (one level above {{{Maildir}}}) and run the script with two arguments: the mailbox name (You can use "." for the top-level folder), and the output mbox filename, for example:

{{{
cd ~hans
perl dw-maildirtombox.pl . >/tmp/hans-inbox
perl dw-maildirtombox.pl Sent >/tmp/hans-sent
}}}
{{{#!plain
#!/usr/bin/env perl
# dw-maildirtombox.pl
# dw = Dovecot Wiki :-)
# NOTE! The output file must not contain single quotes (')!
# figure out which program to run
$cmd="reformail -f1";
system("$cmd </dev/null >/dev/null 2>/dev/null") == 0 or $cmd="formail";
system("$cmd </dev/null >/dev/null 2>/dev/null") == 0
or die "cannot find reformail or formail on your \$PATH!\nAborting";
$dir=$ARGV[0];
$outputfile=$ARGV[1];
if (($outputfile eq '') || ($dir eq ''))
{ die "Usage: ./archivemail.pl mailbox outputfile\nAborting"; }
if (!stat("Maildir/$dir/cur") || !stat("Maildir/$dir/new"))
{ die "Maildir/$dir is not a maildir.\nAborting"; }
@files = (<Maildir/$dir/cur/*>,<Maildir/$dir/new/*>);
foreach $file (@files) {
  next unless -f $file; # skip non-regular files
  next unless -s $file; # skip empty files
  next unless -r $file; # skip unreadable files
  $file =~ s/'/'"'"'/; # escape ' (single quote)
  $run = "cat '$file' | $cmd >>'$outputfile'";
  system($run) == 0 or warn "cannot run \"$run\".";
}
}}}
== Converting from MBX to Maildir ==
See the [[http://wiki.dovecot.org/Migration/UW?action=AttachFile&do=view&target=uw2dovecot.pl|uw2dovecot.pl]] as mentioned on the [[Migration/UW]] page.

== Converting from MBX to mbox ==
If you are using UW-IMAP and using the [[MailboxFormat/mbx|MBX format]], you will need to convert it to [[MailboxFormat/mbox|mbox]] format. The conversion process isn't pretty, but here is a script that works. You will need to get and compile the mailutil program from the [[http://www.washington.edu/imap/|UW-IMAP web site]].

{{{#!plain
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fi}}} fi
}}}
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 * Important - make sure that you changed your SMTP configuration to write MBOX and not MBX.  * Important - make sure that you changed your SMTP configuration to write mbox and not MBX.
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== Converting from MBOX to Maildir ==
[http://batleth.sapienti-sat.org/projects/mb2md/ mb2md] is a script which can convert the files for you.

Check also the '''User-Contributed Maildir Support''' section [http://www.qmail.org/top.html#usersoft on the qmail community site] for more choices.

Example (user's mail in {{{~someuser/mail}}} and inbox in {{{/var/mail/someuser}}}):

{{{
cd ~someuser
mb2md-3.20.pl -s mail -R
mb2md-3.20.pl -m -d /var/mail/incoming/someuser
mv mail mail.old}}}
Now the mail will be in {{{~someuser/Maildir}}}.

If you are migrating from UW-IMAP, you also need to do:

{{{
cp -p .mailboxlist Maildir/subscriptions}}}
Note that maildir handles subdirectories differently. You need to replace "/" with "." in the subscriptions file:

{{{
sed "s/\//\./" subscriptions > subscriptions.new
mv subscriptions.new subscriptions}}}
Don't forget to update {{{mail_location}}} in dovecot.conf (as needed)

== Converting from Maildir to MBOX ==
This is especially helpful if you want to archive your mail to a single file for storage on a CD, a PC, etc. But it can also be helpful if you want to use MBOX with dovecot.

Use the reformail program that comes with [http://www.courier-mta.org/maildrop/ maildrop]. You can also use the formail program that comes with [http://www.procmail.org/ procmail]. Here is a simple script showing how this works.

To use it, adjust the script to invoke the right command according to your system.

Then {{{cd}}} to the user's home directory (one level above {{{Maildir}}}) and run the script with two arguments: the mailbox name (You can use "." for the top-level folder), and the output mbox filename, for example:

{{{
cd ~hans
perl dw-maildirtombox.pl . >/tmp/hans-inbox
perl dw-maildirtombox.pl Sent >/tmp/hans-sent}}}
'''WARNING:''' versions of the script provided here before 2006-05-18 11:40 UTC did not save the new/ directory contents, i. e. they missed unread messages!

{{{
#!/usr/bin/env perl
# dw-maildirtombox.pl
# dw = Dovecot Wiki :-)
# NOTE! The output file must not contain single quotes (')!
# figure out which program to run
$cmd="reformail -f1";
system("$cmd </dev/null >/dev/null 2>/dev/null") == 0 or $cmd="formail";
system("$cmd </dev/null >/dev/null 2>/dev/null") == 0
or die "cannot find reformail or formail on your \$PATH!\nAborting";
$dir=$ARGV[0];
$outputfile=$ARGV[1];
if (($outputfile eq '') || ($dir eq ''))
{ die "Usage: ./archivemail.pl mailbox outputfile\nAborting"; }
if (!stat("Maildir/$dir/cur") || !stat("Maildir/$dir/new"))
{ die "Maildir/$dir is not a maildir.\nAborting"; }
@files = (<Maildir/$dir/cur/*>,<Maildir/$dir/new/*>);
foreach $file (@files) {
  next unless -f $file; # skip non-regular files
  next unless -s $file; # skip empty files
  next unless -r $file; # skip unreadable files
  $file =~ s/'/'"'"'/; # escape ' (single quote)
  $run = "cat '$file' | $cmd >>'$outputfile'";
  system($run) == 0 or warn "cannot run \"$run\".";
}
}}}
 * I did the same (using {{{mailutil}}}) but it doesn't maintain UIDs or UIDVALIDITY. So I hacked [[attachment:mbx2mbox.tgz|this]] together to do the migration. ''-- JulianFitzell, 2008-08-02''
 * Tried to do {{{mailutil -v copy /tmp/foo '#driver.unix'/tmp/foo.unix}}}, but mailutil argues {{{Can't open mailbox /tmp/foo: no such mailbox}}}. (mailutil as from the Debian package uw-mailutils in Debian 5.0 Lenny) strace shows that it searches for /tmp/foo/cur, i.e. a Maildir format mailbox. (WTF?) No idea yet how to get this working. And I'm really glad when I got rid of MBX. -- AxelBeckert, 2009-06-19
  * As Mark Crispin always says: Don't use UW-IMAP with buggy (Maildir) patches, compile your own.
  * Same problem here - just reinstalled uw-imapd, used thunderbird to create a "normal" mailfolder and copied the old folder contents - F.Fernandez
  * At least with ubuntu mailutil from uw-mailutils it starts search from root '''ALWAYS''' and if you start with slash it tries to convert from maildir format {{{mailutil -v copy /tmp/foo '#driver.unix'/tmp/foo.unix}}} = convert maildir formated folder /tmp/foo/cur to mbox and {{{mailutil -v copy tmp/foo '#driver.unix'/tmp/foo.unix}}} = convert /tmp/foo file to mbox - Manwe, 2010-03-09

Converting between mailbox formats

If you want a transparent migration, the biggest problem is preserving message UIDs. See Migration for the problems this may cause. If you do the conversion with dsync, it preserves the UIDs.

dsync

With dsync you can convert between any two mailbox formats that Dovecot supports. As much of the mailbox state is preserved as possible. Typically it's everything. See Tools/Dsync for full documentation, here are only a couple of examples:

  • mbox -> maildir migration. Set mail_location=maildir:~/Maildir and run dsync -u username mirror mbox:~/mail:INBOX=/var/mail/username

  • maildir -> mdbox migration. Set mail_location=mdbox:~/mdbox and run dsync -u username mirror maildir:~/Maildir

  • maildir -> sdbox migration. Set mail_location=sdbox:~/sdbox and run dsync -u username mirror maildir:~/Maildir

If you can successfully use dsync, you can skip the rest of this page.

Converting from mbox to Maildir

Check also the User-Contributed Maildir Support section on the qmail community site for more choices.

Example (user's mail in ~someuser/mail and INBOX in /var/mail/someuser):

cd ~someuser
mb2md-3.20.pl -s mail -R
mb2md-3.20.pl -m -s /var/mail/someuser
mv mail mail.old

Now the mail will be in ~someuser/Maildir. Do not forget to migrate the subscriptions as well, otherwise the new maildir will seem to have only an inbox when viewed through a mail client that supports them. This can be as simple as copying the old ~someuser/mail/.subscriptions file to ~someuser/Maildir/subscriptions (warning: I have not tested this extensively, my subscription list and folder hierarchy was very simplistic).

Hierarchy separator change

The default hierarchy separator with Maildir is '.' instead of '/' which is common with mboxes. To keep the migration transparent to users, you can keep the '/' separator by using namespaces. In any case you need to replace the '/' with '.' in the subscriptions file:

  • sed 's:/:.:g' subscriptions > subscriptions.new
    mv subscriptions.new subscriptions

UW-IMAP's subscriptions file is in ~/.mailboxlist. Dovecot's mbox subscriptions is in <mbox root dir>/.subscriptions. Dovecot's Maildir subscriptions is in <maildir root>/subscriptions.

Also if you're migrating from UW-IMAP, you probably had "mail/" prefixes in the mailbox names. You can again use namespaces to let clients use the prefix, or you can tell your users to remove the namespace prefix from their clients and change the subscriptions file:

sed 's/^mail\.//' subscriptions > subscriptions.new
mv subscriptions.new subscriptions

Note that because Maildir uses '.' as the hierarchy separator in filesystem, it's not possible to have mailbox names containing '.' characters, even if you changed the separator in namespaces. If you really want to have dots, the only way to do this is by modifying the filesystem separator in MAILDIR_FS_SEP and MAILDIR_FS_SEP_S defines in src/lib-storage/index/maildir/maildir-storage.h file in the sources. Do not be tempted to change MAILDIR_FS_SEP et al to '/'; it won't work.

Converting from Maildir to mbox

This is especially helpful if you want to archive your mail to a single file for storage on a CD, a PC, etc. But it can also be helpful if you want to use mbox with Dovecot.

Use the reformail program that comes with maildrop. You can also use the formail program that comes with procmail. Here is a simple script showing how this works.

To use it, adjust the script to invoke the right command according to your system.

Then cd to the user's home directory (one level above Maildir) and run the script with two arguments: the mailbox name (You can use "." for the top-level folder), and the output mbox filename, for example:

cd ~hans
perl dw-maildirtombox.pl . >/tmp/hans-inbox
perl dw-maildirtombox.pl Sent >/tmp/hans-sent

#!/usr/bin/env perl
# dw-maildirtombox.pl
# dw = Dovecot Wiki :-)
# NOTE! The output file must not contain single quotes (')!
# figure out which program to run
$cmd="reformail -f1";
system("$cmd </dev/null >/dev/null 2>/dev/null") == 0 or $cmd="formail";
system("$cmd </dev/null >/dev/null 2>/dev/null") == 0
or die "cannot find reformail or formail on your \$PATH!\nAborting";
$dir=$ARGV[0];
$outputfile=$ARGV[1];
if (($outputfile eq '') || ($dir eq ''))
{ die "Usage: ./archivemail.pl mailbox outputfile\nAborting"; }
if (!stat("Maildir/$dir/cur") || !stat("Maildir/$dir/new"))
{ die "Maildir/$dir is not a maildir.\nAborting"; }
@files = (<Maildir/$dir/cur/*>,<Maildir/$dir/new/*>);
foreach $file (@files) {
  next unless -f $file; # skip non-regular files
  next unless -s $file; # skip empty files
  next unless -r $file; # skip unreadable files
  $file =~ s/'/'"'"'/;  # escape ' (single quote)
  $run = "cat '$file' | $cmd >>'$outputfile'";
  system($run) == 0 or warn "cannot run \"$run\".";
}

Converting from MBX to Maildir

See the uw2dovecot.pl as mentioned on the Migration/UW page.

Converting from MBX to mbox

If you are using UW-IMAP and using the MBX format, you will need to convert it to mbox format. The conversion process isn't pretty, but here is a script that works. You will need to get and compile the mailutil program from the UW-IMAP web site.

#! /bin/sh
# Written by Marc Perkel - public domain
# overhauled by Matthias Andree, 2006
# Usage: mbx-convert <filename>
# This code assumes there a user named "marc" with the primary group "marc".
# Change to any real user on your system.
# Yes - it look bizzare - but it gets the job done
# abort on error
set -e
user=marc
group=marc
homedir=/home/$user
if [ $# -ne 1 ] ; then
  echo >&2 "Usage: $0 <filename>"
  exit 1
fi
# set up automatic cleanup
trap 'rm -f "${homedir}"/in.$$ "${homedir}"/out.$$' 0
# First copy to users home dir and make the user the owner
cp "$1" "${homedir}/in.$$"
chown "$user":"$group" "${homedir}/in.$$"
# Run mailutil to convert as the user other than root
# mailutil requires this
su "$user" -c "mailutil copy in.$$ \#driver.unix/out.$$"
# create new file with same permissions/owner as old
cp -p "$1" "${1}.new"
# cat instead of copy leaves the original owner and permissions alone
if cat "${homedir}/out.$$" >"${1}.new" ; then
  # cat succeeded, rename file into place
  mv "${1}.new" "$1"
else
  # cat failed, remove temp file
  rm -f "${1}.new"
  exit 1
fi

Make a copy of some folders and test it first. Once you are satisfied that it works then:

  • Write a script to convert all your files.
  • Shut down your email system so files can't be modified
  • Copy all your email to a backup location in case you have to revert
  • Run the script
  • Turn on Dovecot and test to verify it is working
  • Important - make sure that you changed your SMTP configuration to write mbox and not MBX.
  • Turn on SMTP and verify it is all working

User comments:

  • Is this hassle actually necessary? I have run mailutil as root like this (mailutil as provided by the PINE 4.61 package for SUSE Linux 10.0): mailutil copy /tmp/foo.mbx.orig '#driver.unix//tmp/foo.test' and did not encounter any problems. -- MatthiasAndree, 2006-05-18

  • I did the same (using mailutil) but it doesn't maintain UIDs or UIDVALIDITY. So I hacked this together to do the migration. -- JulianFitzell, 2008-08-02

  • Tried to do mailutil -v copy /tmp/foo '#driver.unix'/tmp/foo.unix, but mailutil argues Can't open mailbox /tmp/foo: no such mailbox. (mailutil as from the Debian package uw-mailutils in Debian 5.0 Lenny) strace shows that it searches for /tmp/foo/cur, i.e. a Maildir format mailbox. (WTF?) No idea yet how to get this working. And I'm really glad when I got rid of MBX. -- AxelBeckert, 2009-06-19

    • As Mark Crispin always says: Don't use UW-IMAP with buggy (Maildir) patches, compile your own.
    • Same problem here - just reinstalled uw-imapd, used thunderbird to create a "normal" mailfolder and copied the old folder contents - F.Fernandez
    • At least with ubuntu mailutil from uw-mailutils it starts search from root ALWAYS and if you start with slash it tries to convert from maildir format mailutil -v copy /tmp/foo '#driver.unix'/tmp/foo.unix = convert maildir formated folder /tmp/foo/cur to mbox and mailutil -v copy tmp/foo '#driver.unix'/tmp/foo.unix = convert /tmp/foo file to mbox - Manwe, 2010-03-09

None: Migration/MailFormat (last edited 2019-01-11 08:40:22 by AkiTuomi)