On 1/13/15, 6:02 AM, Michael Schwartzkopff wrote:
Am Dienstag, 13. Januar 2015, 21:40:34 schrieb Nick Edwards:
On 1/13/15, Michael Schwartzkopff <m...@sys4.de> wrote:
Hi,
I did some experiments with dovecot on a glusterfs on the active nodes
without
a director. So I had concurrent access to the files.
With the help of the available documentation about NFS and fcntl locks I
managed to find out the following:
With the plain mbox format dovecot seems to apply and to honor the fcntl
locks. But since this format is not used any more in real setups, it is
useless.
With mdbox and maildir format I could reliably crash my mail storage just
by
delivering mails to the both dovecots via LMTP to the same user. In
maildir
dovecot seems not the set / respect the fnctl locks of the index file.
dotlocks
do not seems to work either with mdbox.
So I think the only solution os to use a director in a real world setup.
Or
is
there any non-obvious trick that I did not check?
Interesting, we use NFSv3 dovecot LDA with maildir, we have at present
two dozen front end SMTP servers (using dovecot-lda) and some, hrmm we
added a few more over Christmas, so I think about 32 pop3 servers,
but with only 4 imap servers incl webmail (IMAP is not heavily used
here due to government spy laws) talking to NAS storage server
backend, *we do not use director* at all and has never been an issue.
Director IIRC solves the problem of IMAP inconsistency, but we never
see advantage when we tested, no doubt it solves some fancy setup
problem, but since director can not help with pop3, it was not worth
the hassle. never had any problems with webmail either, load balancers
seem to look after it well
Yes. NFS has its own locking. I wanted to use plain glusterfs client without
the detour of NFS. Thanks for your hint.
Mit freundlichen Grüßen,
Michael Schwartzkopff
The last time we experimented with Glusterfs (two years ago) the native
client was actually not able to maintain consistency as well as the NFS
for a reason that I cannot remember anymore. We used maildir, and when
using NFS we were able to deliver about a hundred thousand emails per
hour and do a couple hundred thousand IMAP and POP3 retrievals per hour
against a modest four node Gluster cluster with four Dovecot/Postfix
servers (running in vmware).
