Hello everybody,

First of all, sorry in advance for my approximate English.

I have several questions. Questions for which I did not find answer until today, despite one very large number of reading of docs, faqs, tickets etc. (I did not necessarily read everything, internet is so vast).

Presentation: I have to migrate all the servers of the company, from ubuntu 10.04.3lts (package openldap 2.4.21) to ubuntu 12.04lts (package openldap 2.4.28).

Configuration: Configuration of openldap, identical on all the servers (Masters and Slaves), configuration of dynamic type (with cn=config ), with reference ldap Masters in the config of slaves ; syncrepl (N-Way) Multi-Master mode. All servers are VMs on kvm.

Questions: Questions according to several scenarios: - there are problems of synchronization between 2 Masters, if the one is in 2.4.21 and the other one in 2.4.28? - there are problems of synchronization between 2 servers, if 1 Master is in 2.4.21 and 1/severals Slave(s) in 2.4.28? - there are problems of synchronization between 2 servers, if 1 Master is in 2.4.28 and 1/several Slaves in 2.4.21? - I want to do an update of part of the slaves servers. What it is better to use?: acl or in syscrepl? Which is the most flexible?

MDB backend: - can one use now the backend-mdb new in "production mode" with openldap 2.4.28? Is it with good/enough stability? Or do I have to stay with the backend-hdb and migrate towards backend-mdb later? - Is it pisible to migrate from backend-hdb towards backend-mdb for server in production, in the future?

Tcmalloc: - I placed tcmalloc in this file '/etc/init.d/slapd' as this "LD_PRELOAD=/usr/lib/libtcmalloc_minimal.so.0". Is it good? Is it the good place/file? - where can I find track of its load (of tcmalloc)? How can I see the functioning of tcmalloc? In what file of log? The LSOF command no give nothing. - it is indicated in the site "[URL="http://code.google.com/r/heybrowny-higmysql/source/browse/google-perftools-1...]"

"TCMALLOC_DEBUG=<level> -- the higher level, the more messages

malloc emits". It is indicated that more the number increase and more tcmalloc verbose. But it is not indicated/informed has what corresponds the numeros (levels) of log and until how much? -to use "TCMALLOC_DEBUG", I have to use "LD_PRELOAD=/usr/lib/libtcmalloc_minimal_debug.so.0" or keep "LD_PRELOAD=/usr/lib/libtcmalloc_minimal.so.0"?

Backups and restore: -the opinions diverge. Indeed, to make a backup/restore, slapadd command is enough with the file created with slapcat? Or i need to integrate (with slapadd) at first the config file (cn=config file) and then the acl config file and then the data of the users that were created at the first installation of openldap 2.4.21?

So, I installed and configured openldap in 2005 on a debian for the needs of a company but today many things changed and difficult to find itself there.

Thank you in advance for taking time and your answers.

Francois ------ Librement