On Wed, Apr 10, 2013 at 09:21:40PM +0300, Timo Sirainen wrote:
> Not if you kick the users out at the correct time:
>
> - dsync
> - switch user to new format
> - kick users
> - final dsync
>
> It doesn't matter if new connections arrive during the final dsync,
> because they are using the new format already. dsync merges changes, it
> doesn't destroy any changes.
It doesn't destroy changes but the user may see an incorrect state for a small
amount of time, doesn't he ?
For instance (using dsync to change Maildir location from file1 to filer2) :
. Maildir in source : message tagged as New
. initial dsync
. user read the message in the source, message is now tagges as Read
. switch user to Maildir in destination
. kick user
. user reconnects and sees, in destination, the message he just read tagged
as New as long as the final dsync is not finished
?
--
Thomas Hummel | Institut Pasteur
<hum...@pasteur.fr> | Groupe Exploitation et Infrastructure
