On Wed, Jun 12, 2013 at 02:27:05PM +0200, Robert Schetterer
wrote:> Hi @ll i have a question about feature
> Shared Writeable MMAP and its relation to concurent file use.
>
> Background, over years i am hosting dovecot imap servers behind
> loadbalancers on a drbd master/master setup shared formated storage
> ocfs2 1.4.3 maildir without problems.
>
> the dovecot wiki says
>
> http://wiki2.dovecot.org/Director
>
> Director can be used by Dovecot's IMAP/POP3/LMTP proxy to keep a
> temporary user -> mail server mapping. As long as user has simultaneous
> connections, the user is always redirected to the same server. Each
> proxy server is running its own director process, and the directors are
> communicating the state to each others. Directors are mainly useful for
> setups where all of the mail storage is seen by all servers, such as
> with NFS or a cluster filesystem
>
> so the director service is most installed on the loadbalancers mainly
> with nfs storage, proved to be a "must have"
>
> after online investigation and long lasting reality tests , i guess
"or
> a cluster filesystem " isnt true for ocfs2, cause on drbd it works
fine
> with concurent files use ( i.e mailbox format maildir ) by feature
> Shared Writeable MMAP.
>
> Can sombody confirm this, or teach in easy words how it works ( or not )
> and why ?
I'm not sure what you are asking. I *think* you are saying,
"ocfs2 is not a sufficient cluster filesystem for Dovecot, because it
does not have shared writeable mmap(2)." If that's what you are
saying,
then you are incorrect. Shared writeable mmap(2) is a very standard
feature of ocfs2; we can't be POSIX without it.
I also don't understand how you are configured. Because it
sounds like you are using ocfs2+drbd successfully, which conflicts with
your statement that ocfs2 is not a sufficient cluster filesystem.
Joel
>
>
> Best Regards
> MfG Robert Schetterer
>
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