Am 12.06.2013 20:56, schrieb Joel Becker: > 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
no my meaning is reverse of that, i am running it fine since years , but others believe using a director service on the loadbalancer is a "must have" avoiding concurent use of shared maildir storage and dovecot indexes, which is definite true for nfs, but for my understanding its not needed using drbd/ocfs2 cause of feature i.e Shared writeable mmap or additional features. In using that setup over years without directors, i didnt noticed any errors nor i could produce one with file tests or with imap clients , 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. sorry ,descriptions of what exact "Shared writeable mmap" is, is hard to understand for none kernel hackers which are not natural english speakers, so i asked for clarification > > Joel > >> >> >> Best Regards >> MfG Robert Schetterer >> >> -- >> [*] sys4 AG >> >> http://sys4.de, +49 (89) 30 90 46 64 >> Franziskanerstraße 15, 81669 München >> >> Sitz der Gesellschaft: München, Amtsgericht München: HRB 199263 >> Vorstand: Patrick Ben Koetter, Axel von der Ohe, Marc Schiffbauer >> Aufsichtsratsvorsitzender: Florian Kirstein >> >> _______________________________________________ >> Ocfs2-users mailing list >> Ocfs2-users@oss.oracle.com >> https://oss.oracle.com/mailman/listinfo/ocfs2-users > Best Regards MfG Robert Schetterer -- [*] sys4 AG http://sys4.de, +49 (89) 30 90 46 64 Franziskanerstraße 15, 81669 München Sitz der Gesellschaft: München, Amtsgericht München: HRB 199263 Vorstand: Patrick Ben Koetter, Axel von der Ohe, Marc Schiffbauer Aufsichtsratsvorsitzender: Florian Kirstein _______________________________________________ Ocfs2-users mailing list Ocfs2-users@oss.oracle.com https://oss.oracle.com/mailman/listinfo/ocfs2-users
