[Kde-pim] Keep computers in sync

[Andras Mantia]

Hi,

 Last night we chatted a little about this on IRC, but I'd like to take 
it to broader attention the issue I faced: I have two computers, a 
desktop and a laptop. I use both IMAP and POP3 mails with delete on the 
server, as 
1) I don't really know how much space I have on the server
2) I used those servers for years (8+ years) and I have thousands and 
gigabytes of email already locally.

There is always one main computer, where KMail is running, on the other 
it is set to offline mode. This worked fine with KMail 1, all I had to do 
is to rsync the maildir folders (both where POP3 mail is downloaded and 
where the DIMAP cache is). So when I went on the road, I synced the 
mails and used the laptop, once I got back home, did the other way and 
used the desktop.
 
Now I faced a problem: how to do this with Akonadi based KMail? My first 
problem was KMail2-KMail1 sync, because the laptop is not running trunk, 
but I'd accept a KMail2-KMail2 sync solution as well.

Theoretically KMail2 still stores the pop3 mails in maildir, so that can 
be synced, but seems the atm maildir support is somewhat broken, the 
maildir folders doesn't really look like in KMail1 (messages are in the 
new folder with a unique name that doesn't seem to follow the maildir 
standard, not moved to cur and status information is not encoded in the 
filename as it should), deleted mails are not deleted from the disk and 
moved mails sometimes(?) are not moved to the destination folder. This 
will become obvious once KMail1 is run on KMail2 maildir folders.
These are bugs and I have hopes that if they are fixed, rsync can be used 
again for maildir and will work.

Still one would like to sync not only POP3 mails, but the IMAP cache as 
well if possible, and even more the metadata associated with the IMAP 
mails (or anything else akonadi related). What would be the solution in 
that case? Copying the mysql db and all akonadi config might be a 
solution, but I fear it will work only between computers running the 
same mysql version and you have to be sure to stop mysql on both 
machines and set them to offline mode. What to you suggest?
 
 And here comes another issue: offline mode. With KMail1 you set Offline 
mode and you were sure no mail is downloaded. With KMail2 it is not that 
easy. Yes, you have offline mode, but it sets only the mail agents to 
offline. If you sync the akonadi db, this is not enough, other apps (e.g 
lionmail, mail notifier plasmoid, kaddressbook, akgreator, whatever) can 
modify the db->data loss. Well, even KMail in offline mode *can* modify 
the database. I was thinking of a global offline mode for the server, 
which turns all agents to offline mode and doesn't allow them becoming 
online without informing the user, but this doesn't solve the problem 
applications doing modifications in the db. Some might say this is also a 
problem without a database, and I agree, with the note that in that case 
only KMail was affected, while now more apps, anything using akonadi.
 A global offline mode would already be a step forward, as no application 
could turn agents online without notifying the user. Now KMail could go 
offline and another mail related app turn it online without the user 
knowing it. And if then a POP3 mail is downloaded and deleted from the 
server, this could result in data loss.

 Sorry for the long mail, I think this is an important issue and right 
now I'm not sure what would be the real solution, so I wait for 
feedback. Please don't tell to use IMAP for it, as this is not the point 
(and requires a server always accessible with "unlimited" space that 
most user will not have), the same could happen with any app and server 
combination, where the data is deleted from the server once it is 
downloaded, not only for POP3 mails.

Andras
 
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