[Dovecot] Using a namespace for providing access to mail snapshots for user based on-demand restoration of email backups

[Charles Marcus]

On 2012-04-05 12:37 PM, Tom Hendrikx <tom at whyscream.net> wrote:
> The first interesting point I'd see with this, is that you supply the
> mail client with a near endless supply of folders, which would take a
> lot of caching space on the clients end, either (depending on the client
> and its configuration) from the moment that you enable this fort hem, or
> after someone starts searching in their 'time machine' for some old mail.
>
> I see my mail client on a new install working quite hard to download
> mail headers for 2 years of postfix/dovecot/etc mailing lists, so what
> happens if you provide a 'time machine' namespace going 1 month back, 4
> with snapshots a day (i.e. 31x4 =~ 120 times more headers to
> download/index).

Interesting and valid point... hmmmm.....

First, these folders would be read-only - a user could copy something 
from there back to one of his other folders, but couldn't write anything 
in them - so nothing would be changing under this namespace, except new 
snapshots magically appearing, which means that once they are indexed, 
the indexes would never need to be rebuilt (unless they got corrupted 
somehow).

But, yeah, I can imagine some problems especially if someone has a ton 
of email. And while these would probably only be accessed rarely, in 
those cases where someone would want to access them, they would very 
likely want to be able to search, so disabling indexes wouldn't be a 
good idea...

Since we use Thunderbird, I can of course disable offline mode for 
everyone, so the only time headers would be downloaded would be when 
the user selects (or performs a search on) one (or more) of the folders.

Maybe Timo can think of something creative to minimize this problem...

-- 

Best regards,

Charles