Using openldap 2.4.39 on solaris 10 sparc box. 
Bdb runs without any issue. Mdb fails on startup ( described below)


Snip from the slapd.conf
-------------------------------------

database        mdb
suffix          "o=vtec,c=au"
rootdn          "cn=manager,o=vtec,c=au"
# Cleartext passwords, especially for the rootdn, should
# be avoid.  See slappasswd(8) and slapd.conf(5) for details.
# Use of strong authentication encouraged.
rootpw          secret
# The database directory MUST exist prior to running slapd AND
# should only be accessible by the slapd and slap tools.
# Mode 700 recommended.
directory       /data/irene/var/openldap-data-mdb
maxsize   1073741824


Get this error on startup
--------------------------------------

34628c3     1.2.36.79672281.1.13.3 (rdnMatch): 534628c3     2.5.13.1 (distinguishedNameMatch): 534628c3 matchingRuleUse: ( 2.5.13.1 NAME 'distinguishedNameMatch' APPLIES ( creatorsName $ modifiersName $ subschemaSubentry $ entryDN $ namingContexts $ aliasedObjectName $ dynamicSubtrees $ distinguishedName $ seeAlso $ olcDefaultSearchBase $ olcRootDN $ olcSchemaDN $ olcSuffix $ olcUpdateDN $ olcRelay $ member $ owner $ roleOccupant ) )
534628c3     2.5.13.0 (objectIdentifierMatch): 534628c3 matchingRuleUse: ( 2.5.13.0 NAME 'objectIdentifierMatch' APPLIES ( supportedControl $ supportedExtension $ supportedFeatures $ supportedApplicationContext ) )
534628c3 slapd startup: initiated.
534628c3 backend_startup_one: starting "cn=config"
534628c3 config_back_db_open
Backend ACL: access to *
        by * none

534628c3 config_back_db_open: line 0: warning: cannot assess the validity of the ACL scope within backend naming context
534628c3 config_back_db_open: No explicit ACL for back-config configured. Using hardcoded default
534628c3 config_build_entry: "cn=config"
534628c3 config_build_entry: "cn=schema"
534628c3 >>> dnNormalize: <cn={0}core>
534628c3 <<< dnNormalize: <cn={0}core>
534628c3 config_build_entry: "cn={0}core"
534628c3 config_build_entry: "olcDatabase={-1}frontend"
534628c3 config_build_entry: "olcDatabase={0}config"
534628c3 config_build_entry: "olcDatabase={1}mdb"
534628c3 backend_startup_one: starting "o=vtec,c=au"
534628c3 mdb_db_open: "o=vtec,c=au"
534628c3 mdb_db_open: database "o=vtec,c=au": dbenv_open(/data/irene/var/openldap-data-mdb).
534628c3 mdb_db_open: database "o=vtec,c=au": mdb_dbi_open(/data/irene/var/openldap-data-mdb/id2e) failed: MDB_BAD_TXN: Transaction cannot recover - it must be aborted (-30782).
534628c3 backend_startup_one (type=mdb, suffix="o=vtec,c=au"): bi_db_open failed! (-30782)
534628c3 slapd shutdown: initiated
534628c3 slapd destroy: freeing system resources.
534628c3 slapd stopped.