Over the past few weeks, I have been testing OpenLDAP as a backend for Samba4. I've been working with the OpenLDAP team on my requirements, and there has been some really good outcomes - the memberOf module has been improved, as has the refint module. However, I seem to have hit a brick wall, in the form of (internal) transaction support. I need an LDAP backend to support internal transactions - that is, when for example a 'member' modification is made, all the memberOf attributes must be updated before the call returns. Similarly, if a user or group moves, all the member/memberOf attributes that link the user to their groups must also move, before the modrdn returns. The Samba4 test ldap.js tests this behaviour extensively, because I want to be sure it works. As understand the discussion I've had with the OpenLDAP team, OpenLDAP does not support this, and will not support it for perhaps some time. Similarly, from discussions with the Fedora DS team at the CIFS developer days, I understand that it is similarly very unlikely that Fedora DS will support internal transactions. (It also does not support subtree renames, which we also need). The fact that LDAP does not expose a transaction API was always going to be a difficult part of having Samba4 use an LDAP backend, but I always assumed that if we pushed the really hard bit - updating linked attributes - into the LDAP server that we could at least always have a consistent DB. (It turns out this is one of the primary uses of transactions anyway.) But without that consistency, and without knowing as a caller if all the updates succeed, I'm worried about how we can safely move forward. This is especially disappointing because I was hoping that these free, replicating LDAP servers might solve the backed replication problem for me, without needing to use AD replication. Does anybody have any ideas or suggestions on how I could get around this? Should we drop the LDAP backend as a nice idea, but not going to work, and focus on DRS or some other form of replication? Can someone imagine a sane way to reconstruct the DN links, including subtree renames, without the help of the LDAP backend? Could we ban subtree renames (as Fedora DS does), and try to handle this ourselves (with pre/post checks and a good deal of prayer)? Thanks, Andrew Bartlett -- Andrew Bartlett http://samba.org/~abartlet/ Authentication Developer, Samba Team http://samba.org Samba Developer, Red Hat Inc.
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