W/o downtime: see the wiki page below, the "Converting" section. Briefly for my case something like this should work and generally seems simple (no syntax checking yet, pseudo-code like):

• Configuration uses mail_location = mbox:~/mails
• setup per-user mail location and do for each user individually in a serial manner: -- doveadm sync maildir:~/Maildir; mbox is synced to Maildir, long running time -- doveadm sync maildir:~/Maildir; rerun to do it for new messages (fast) -- add USER to userdb and set extra field to maildir:~/Maildir users not present in the userdb should default to dovcot default; conditionally optional: doveadm auth cache flush -- doveadm kick (to force clients of USER to use the new Maildir) -- doveadm sync -R mbox:~/mails (rerun to sync the very last few mails, which arrived during the editing and reloading the userdb config)
• when done for all users, I set maildir:~/Maildir for mail location and remove the userdb file definition

The problem of postfix/procmail: procmail; https://wiki2.dovecot.org/HowTo/PostfixDovecotLMTP

• I found this, but I do not prefer edit procmail config this way http://dmc1961.id.au/howto_17101101.php
• I think that dovecot/lmpt is a better solution: -- dovecot takes care of the delivery and it will also know where to deliver during the mixed situation -- on the long term: told to have better performance compared to

On 2019. 01. 29. 19:49, Marc Roos wrote:

I am also migration away from mbox to in my case mdbox. I am not fully aware of something that allows you to do this without downtime.

To try to do as much as possible online, I have created an archive namespace and am moving the larger >5GB mbox files with old emails to that. So when the time is there to do convert active mailboxes, I have less to convert. Maybe this is helpful.

-----Original Message----- From: Tamas Hegedus [mailto:tamas@hegelab.org] Sent: 29 January 2019 17:39 To: dovecot@dovecot.org Subject: mbox 2 Maildir

Hi,

I am not an professional system admin, but I am running a small debian mail server for many years. It is time to migrate from mbox to Maildir. There is a nice and clean description for doing this without service downtime at https://wiki.dovecot.org/Tools/Doveadm/Sync I have to set per-user config for mailbox type using userdb extra fields.

However, I miss some information and I can not find useful info by google.

1. The main question: dovecot will know that for some users the mailbox format is still mbox, but others already have Maildir. I do not see any hint that I should setup postfix/procmail for handling the delivery per-user basis. But I think I have to set this, too.

2. I have not learned much about userdb and it seems that dovecot was written for and used by experts. I mean that the docs/wiki is not enough for me: from the wiki page of userdb it will be for me difficult to setup one. Can you suggest some docs for dummies?

Thanks for your help, Tamas

dovecot --version 2.2.27 (c0f36b0) postfix 3.1.8 procmail v3.23pre 2001/09/13

-- Tamas Hegedus, PhD Senior Research Fellow MTA-SE Molecular Biophysics Research Group Hungarian Academy of Sciences | phone: (36) 1-459 1500/60233 Semmelweis University | fax: (36) 1-266 6656 Tuzolto utca 37-47 | mailto:tamas@hegelab.org Budapest, 1094, Hungary | http://www.hegelab.org

---

This email has been checked for viruses by AVG. https://www.avg.com

-- Tamas Hegedus, PhD Senior Research Fellow MTA-SE Molecular Biophysics Research Group Hungarian Academy of Sciences | phone: (36) 1-459 1500/60233 Semmelweis University | fax: (36) 1-266 6656 Tuzolto utca 37-47 | mailto:tamas@hegelab.org Budapest, 1094, Hungary | http://www.hegelab.org

Tamas Hegedus, 29.01.19:

...

• Configuration uses mail_location = mbox:~/mails
• setup per-user mail location and do for each user individually in a serial manner: -- doveadm sync maildir:~/Maildir; mbox is synced to Maildir, long running time [1] -- doveadm sync maildir:~/Maildir; rerun to do it for new messages (fast) -- add USER to userdb and set extra field to maildir:~/Maildir users not present in the userdb should default to dovcot default; [2] the conditionally optional: doveadm auth cache flush

More or less how I would plan a migration, but to be fanatically safe and avoiding race conditions where a user could be manipulating their mailbox or new having mail delivered, I would put some service mutex between [1] and [2].

By that I mean at [1]

a) tempfail any incoming mail for that user; and

b) kick the user off IMAP/POP and make sure they can't log back
in during the final synching.  (Add them to separate deny userdb?)

After the final sync [2], undo these steps.

Joseph Tam <jtam.home@gmail.com>

Sorry. I had wrong syntax. Missing "mbox:" It is OK with this: doveadm sync -RD mbox:~/mail/

On 02/05/2019 10:48 AM, Tamas Hegedus wrote:

Hi,

I am experimenting with the migration. I unset mail_location, thus it is empty and dovecot performs automatic mailbox detection. Therefore I do not need per-user set of mail location. I login as a testuser and do: doveadm sync maildir:~/Maildir

It seems for me that in this situation the new Maildir becomes the active mail delivery location at the time of the creation(?) or completing the sync(?).

So if I want to rerun to avoid loosing new messages: doveadm sync maildir:~/Maildir I got an error that I can not sync to itself.

I guess this would not be a problem and would be rather simply. However, if I issue a revers sync to be sure not loosing new messages: doveadm sync -R mail/ doveadm(hegedus): Fatal: execvp(mail/) failed: Permission denied dsync-local(hegedus): Error: read(remote) failed: EOF (version not received)

(I tried to set a+x on my old mbox 'mail' directory and its contents)

I would appreciate any suggestion. Thanks, Tamas

On 01/30/2019 03:32 PM, Christian Schmidt wrote:

...

Hi,

Tamas Hegedus, 29.01.19:

...

• Configuration uses mail_location = mbox:~/mails
• setup per-user mail location and do for each user individually in a serial manner: -- doveadm sync maildir:~/Maildir; mbox is synced to Maildir, long running time -- doveadm sync maildir:~/Maildir; rerun to do it for new messages (fast) -- add USER to userdb and set extra field to maildir:~/Maildir users not present in the userdb should default to dovcot default; conditionally optional: doveadm auth cache flush

IMHO there is no need to create or change special userdb entries. See https://wiki.dovecot.org/MailLocation: "By default the mail_location setting is empty, which means that Dovecot attempts to locate automatically where your mails are."

Regards, Christian

-- Tamas Hegedus, PhD Senior Research Fellow Department of Biophysics and Radiation Biology Semmelweis University | phone: (36) 1-459 1500/60233 Tuzolto utca 37-47 | mailto:tamas@hegelab.org Budapest, 1094, Hungary | http://www.hegelab.org

Dear Marc, Thanks for pointing this small but very important detail - it simplifies the process so much! Tamas

On 01/29/2019 09:22 PM, Tamas Hegedus wrote:

W/o downtime: see the wiki page below, the "Converting" section. Briefly for my case something like this should work and generally seems simple (no syntax checking yet, pseudo-code like):

• Configuration uses mail_location = mbox:~/mails
• setup per-user mail location and do for each user individually in a serial manner: -- doveadm sync maildir:~/Maildir; mbox is synced to Maildir, long running time -- doveadm sync maildir:~/Maildir; rerun to do it for new messages (fast) -- add USER to userdb and set extra field to maildir:~/Maildir users not present in the userdb should default to dovcot default; conditionally optional: doveadm auth cache flush -- doveadm kick (to force clients of USER to use the new Maildir) -- doveadm sync -R mbox:~/mails (rerun to sync the very last few mails, which arrived during the editing and reloading the userdb config)
• when done for all users, I set maildir:~/Maildir for mail location and remove the userdb file definition

The problem of postfix/procmail: procmail; https://wiki2.dovecot.org/HowTo/PostfixDovecotLMTP

• I found this, but I do not prefer edit procmail config this way http://dmc1961.id.au/howto_17101101.php
• I think that dovecot/lmpt is a better solution: -- dovecot takes care of the delivery and it will also know where to deliver during the mixed situation -- on the long term: told to have better performance compared to

On 2019. 01. 29. 19:49, Marc Roos wrote:

...

I am also migration away from mbox to in my case mdbox. I am not fully aware of something that allows you to do this without downtime.

To try to do as much as possible online, I have created an archive namespace and am moving the larger >5GB mbox files with old emails to that. So when the time is there to do convert active mailboxes, I have less to convert. Maybe this is helpful.

-----Original Message----- From: Tamas Hegedus [mailto:tamas@hegelab.org] Sent: 29 January 2019 17:39 To: dovecot@dovecot.org Subject: mbox 2 Maildir

Hi,

I am not an professional system admin, but I am running a small debian mail server for many years. It is time to migrate from mbox to Maildir. There is a nice and clean description for doing this without service downtime at https://wiki.dovecot.org/Tools/Doveadm/Sync I have to set per-user config for mailbox type using userdb extra fields.

However, I miss some information and I can not find useful info by google.

1. The main question: dovecot will know that for some users the mailbox format is still mbox, but others already have Maildir. I do not see any hint that I should setup postfix/procmail for handling the delivery per-user basis. But I think I have to set this, too.

2. I have not learned much about userdb and it seems that dovecot was written for and used by experts. I mean that the docs/wiki is not enough for me: from the wiki page of userdb it will be for me difficult to setup one. Can you suggest some docs for dummies?

Thanks for your help, Tamas

dovecot --version 2.2.27 (c0f36b0) postfix 3.1.8 procmail v3.23pre 2001/09/13

-- Tamas Hegedus, PhD Senior Research Fellow MTA-SE Molecular Biophysics Research Group Hungarian Academy of Sciences | phone: (36) 1-459 1500/60233 Semmelweis University | fax: (36) 1-266 6656 Tuzolto utca 37-47 | mailto:tamas@hegelab.org Budapest, 1094, Hungary | http://www.hegelab.org

---

This email has been checked for viruses by AVG. https://www.avg.com

-- Tamas Hegedus, PhD Senior Research Fellow Department of Biophysics and Radiation Biology Semmelweis University | phone: (36) 1-459 1500/60233 Tuzolto utca 37-47 | mailto:tamas@hegelab.org Budapest, 1094, Hungary | http://www.hegelab.org