shared database for multile mx hosts

[jaywe...@gmail.com]

We have multiple equal preference MX hosts for load/capacity reasons. We installed greyfix, and rather immediately noticed delays as the greyfix database is not shared amongst the multiple MX hosts.

I see on the main web page a discussion of handling this via a dedicated greyfix server. Makes sense, but... questions:

1) Instead of setting up a separate greyfix server, can we just share the greyfix database amongst the mx hosts via NFS? Specifically, is greyfix known to be "nfs safe" with regards to locking, etc. ?

or

2) If we go the route of setting up a greyfix server, as the web site states this is a single point of failure. What will postfix do if the greyfix server is down? Will it stop delivering email or will it continue without greyfix checks or will it TMPFAIL emails?

Thanks for any direction/input you can provide!

Best,

Jay West

[Kim Minh Kaplan]

jaywe...@gmail.com wrote:

> 1) Instead of setting up a separate greyfix server, can we just share the greyfix database amongst the mx hosts via NFS? Specifically, is greyfix known to be "nfs safe" with regards to locking, etc. ?

Greyfix relies on Berkeley DB to handle storage and concurrent access.
But Berkeley DB does not support concurrent access via NFS through
different computers. So no, sharing Greyfix database through NFS is
not supposed to work.

See http://www.oracle.com/technetwork/database/berkeleydb/db-faq-095848.html#CanBerkeleyDBuseNFSSANorotherremotesharednetworkfilesystemsfordatabasesandtheirenvironments

> 2) If we go the route of setting up a greyfix server, as the web site states this is a single point of failure. What will postfix do if the greyfix server is down? Will it stop delivering email or will it continue without greyfix checks or will it TMPFAIL emails?

In most cases Postfix will signal a temporary failure (SMTP 451
4.3.5). If Greyfix somehow manages to detect its own failure then it
will let the email through.

Kim Minh.