Hello,
We are running a director-based dovecot cluster where the user's maildir and
the indexes/control files are, for legacy reasons, stored on separate
NFS-backends, i.e.:
mail_location =
maildir:~/Maildir:CONTROL=/mail/control/%1u/%2u/%u:INDEX=/mail/index/%1u/%2u/%u
Both ~/Maildir and /mail/{control,index}/ are separate NFS-mounts, and we now
want to consolidate all files to the user's home directory instead. The end
goal is to stop using NFS altogether.
I have devised a four step plan for gradually migrating the index/control files
into the user's maildir, on a per-user basis:
1. Kick the user in an attempt to flush the user's index files:
`doveadm director kick <username>`
2. Rsync the index/control files into the user's maildir:
`rsync -uav /mail/{index,control}/${user:0:1}/${user:0:2}/${user}/
/mail/${user:0:1}/${user:0:2}/${user}/Maildir/;`
3. Update the (redis-based) userdb for the specific user to override
mail_location to use the default CONTROL/INDEX locations:
`{"mail": "maildir:~/Maildir"}`
4. Kick the user one last time so that they reconnect using the new settings.
Unfortunately, after running this for a small batch of users, we recieved a
couple reports that their clients had started to resynchronize and redownload
their mailboxes, which is exactly what we're trying to avoid. There are no
index related error messages related to the few users that reported these
issues.
From my understanding, clients become confused when the control files are
changed or lost (`dovecot-uidlist` and `dovecot-uidvalidity`), so I suspect the
kick + rsync + kick procedure is not robust enough for this.
Does anyone have any experience with performing such a migration without taking
systems offline for the duration? Any suggestions to make this process more
transparent for our users, so as to not induce panic when their mailboxes
abruptly appear empty?
Best regards,
Eirik
Hi, i think you cannot do this without preventing users to log in. We were doing similar thing few years ago and i wrote a Python script for this purpose - you can use it if you find it usefull (script is copying only control files as indexes are transparently recreated): Cit?t Eirik Rye <rye at trojka.no>:> Hello, > > We are running a director-based dovecot cluster where the user's > maildir and the indexes/control files are, for legacy reasons, > stored on separate NFS-backends, i.e.: > > mail_location = > maildir:~/Maildir:CONTROL=/mail/control/%1u/%2u/%u:INDEX=/mail/index/%1u/%2u/%u > > Both ~/Maildir and /mail/{control,index}/ are separate NFS-mounts, > and we now want to consolidate all files to the user's home > directory instead. The end goal is to stop using NFS altogether. > > I have devised a four step plan for gradually migrating the > index/control files into the user's maildir, on a per-user basis: > > 1. Kick the user in an attempt to flush the user's index files: > > `doveadm director kick <username>` > > 2. Rsync the index/control files into the user's maildir: > > `rsync -uav /mail/{index,control}/${user:0:1}/${user:0:2}/${user}/ > /mail/${user:0:1}/${user:0:2}/${user}/Maildir/;` > > 3. Update the (redis-based) userdb for the specific user to override > mail_location to use the default CONTROL/INDEX locations: > > `{"mail": "maildir:~/Maildir"}` > > 4. Kick the user one last time so that they reconnect using the new settings. > > Unfortunately, after running this for a small batch of users, we > recieved a couple reports that their clients had started to > resynchronize and redownload their mailboxes, which is exactly what > we're trying to avoid. There are no index related error messages > related to the few users that reported these issues. > > From my understanding, clients become confused when the control > files are changed or lost (`dovecot-uidlist` and > `dovecot-uidvalidity`), so I suspect the kick + rsync + kick > procedure is not robust enough for this. > > Does anyone have any experience with performing such a migration > without taking systems offline for the duration? Any suggestions to > make this process more transparent for our users, so as to not > induce panic when their mailboxes abruptly appear empty? > > Best regards, > Eirik
> On 26 Apr 2021, at 15:14, Eirik Rye <rye at trojka.no> wrote: > > Both ~/Maildir and /mail/{control,index}/ are separate NFS-mounts, and we now want to consolidate all files to the user's home directory instead. The end goal is to stop using NFS altogether.Some more background information: - Running 2.3.13 (89f716dc2) - The rsync is run from the user's current mapped backend (from `doveadm director status <user>`), in hopes to reduce NFS-related issues - Kicking is done through one of the directors, to ensure all of the user's connections are kicked. Best regards, Eirik