stroboscope / reopenldap

aka "Telco LDAP" - the rework of well-known OpenLDAP with a lot of heisenbugs fixing, mostly for replication.

ReOpenLDAP is...

1. Also known as "TelcoLDAP" - is the telco-oriented fork of OpenLDAP.
2. A number of new features, most of which deal with highload and multi-master clustering.
3. Bug fixing and code quality improvement.

But no Windows, Mac OS, FreeBSD, Solaris or HP-UX; just only Linux!

ReOpenLDAP is currently running in telcos across Russia:

• Several 2x2 multi-master clusters
• Up to ~100 million records, up to ~100 GB of data
• Up to ~10K updates per second, up to ~25K searches

No other LDAP server can provide this level of performance now (due to replication failures, inadequate performance or high risk of a crash).

ReOpenLDAP preamble

We consider that the original OpenLDAP project was failed due the following reasons:

• disregard for support by community and code clarity.
• giant technical debt and incredible low code quality.
• unreasonable desire to support the wide range of an obsolete archaic systems and compilers.

Change List

Below is a list of changes made within the ReOpenLDAP project. For a description of the new features, please see the man page for slapd.conf. For the changes merged from OpenLDAP project, please see the CHANGES.OpenLDAP file.

Features (major):

• multi-master replication is working properly and robustly (it seems no other LDAP server can do this)
• reopenldap [iddqd] [idkfa] [idclip]
• quorum { [vote-sids ...] [vote-rids ...] [auto-sids] [auto-rids] [require-sids ...] [require-rids ...] [all-links] }
• quorum limit-concurrent-refresh
• biglock { none | local | common }
• storage (mdbx): dreamcatcher & oom-handler (ITS#7974)
• storage (mdbx): lifo & coalesce (ITS#7958)
• storage (mdbx): steady & weak datasync
• bundled with all known contributed modules/overlays/plugins

Features (minor):

• syncprov-showstatus { none | running | all }
• crash-backtrace on|off
• coredump-limit <mbytes>
• memory-limit <mbytes>
• checkpoints by volume-of-changes and periodically in seconds
• syncrepl's requirecheckpresent option
• keepalive <idle>:<probes>:<interval> for incoming connections
• built-in memory checker, including ls-malloc
• ready for AddressSanitizer and Valgrind
• ready for LTO (Link-Time Optimization) by GCC and clang
• support for OpenSSL 1.1.x, Mozilla NSS, GnuTLS and LibreSSL 2.5.x

Fixes:

• all from openldap/master and openldap/2.4 branches
• a lot for replication, especially for multi-master
• removed ~5K warnings from GCC/clang
• removed ~1K warnings from ThreadSanitizer (a data race detector)
• removed most of memory leaks (tests could be passed under Valgrind)
• checked with PVS-Studio static analyser, see details
•