offlineimap smart backup synchronization = bidirectional synchronization without deleting any messages

[proxym]

No no no...
I don't want to use snapshots/tarbals. I just want bidirectional
append only mode switch in OfflineIMAP and it's config file. Also I
need allowing for editing of Drafts as exception in bidirectional
append mode.

I already fixed this problem partially. But fix is ugly: I just call cp -al
command to create hard links of all my letters (messages) after
offlineimap finish synchronization. As you know every file already has
counter of hard links to him with value 1. It is in
ext2/ext3/ext4/ntfs file systems.
cp -al just create something which I can name as new "file header" and
increase hard link counter of file. If counter is 0, then no hard
links exists anymore (file is totally removed from file system and
will be rewrited by something else later). So hard links is good
temporary solution for me.
Hard links additional "headers" takes 44M for 1,4G Mail folder in my
ext3 file system now.

I don't want tarbals. I choosed Maildir format specially, because it
keeps one message by file (actually in raw email format, which is
better). Even in case of file system damage I can restore most of my
messages because of Maildir.

I know some people, which lost half or even all mail messages, because
Google just cleaned their Gmail mailboxes by unknown reason (support
answered that messages are not restorable). Offlineimap will remove
local copy of messages in this case while next synchronuzation without
any warning. Removing of messages by Google is in TERMS AND CONDITIONS
of Gmail, if you did not know. Same is for any other free Mail server
(maybe for non-free too).


Maybe I don't know something about 'readonly' option... I thought it
makes Maildir Mailbox not writable at all and it is not possible to
add new email massages when readonly option is activated... Maybe I am
not right... ?

Thank you.

2012/12/3 Nicolas Sebrecht <nicolas.s-dev at laposte.net>:
> On Sat, Dec 01, 2012 at 05:15:32PM +0300, proxym wrote:
>> Offlineimap does bidirectional synchronization, but it is not smart,
>> it's has not any options to configure behavior for deleting messages.
>>
>> I just want to do bidirectional synchronization without deleting
>> anything ALWAYS. How can I get it with offlineimap?
>
> You need more than OfflineIMAP for what you expect. Coupling OfflineIMAP
> with tarballs/snapshots of the local maildir could do the trick in your
> case.
>
> OfflineIMAP alone can be used as a backup tool ('readonly' option helps
> for the purpose) at the condition that the state of the mailbox is
> _known_ to be correct (so, the sync IS the backup). OfflineIMAP does not
> intend to provide history of backups or anything more advanced.
>
> --
> Nicolas Sebrecht