While it is possible to direct write traffic to any provider in a
multi-provider environment, it is better to direct writes to only one
provider at a time and keep the other providers as standbys to take
write traffic if the primary provider fails.
Server Configuration
Replication depends heavily on accurate timing. Make sure that all
provider and consumer system clocks are synchronized with NTP or similar
service.
High Availability
Designate which consumers are candidates for promotion and
pre-configure slapd.conf (or ldif to update dynamic config) and ensure
all backend configurations/folder structures are identical to the
current provider
If using SSL/TLS for communication between servers, make sure that
the security certificates on all replicas are valid for communication
with the new provider