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Re: Replication & efficiency question
"Koszegi, Kelley" wrote:
>
> Hello,
>
> In the admin guide, chapter 10
> (http://www.openldap.org/doc/admin/replication.html) states that, "In
> certain configurations, a single slapd(8) instance may be insufficient to
> handle the number of clients requiring directory service via LDAP. It may
> become necessary to run more than one slapd instance." Then it goes on to
> give a sample replication scenario in which a client first requests a modify
> operation of a slave, is referred to the master, requests a modify operation
> of the master and the master performs the operation. The master also writes
> a change to a replication file. The slurpd process then notifies the slave
> of the change.
>
> Here is my question: how is this process going to handle a larger number of
> clients? It seems to me that each client is now forced to endure both a
> request to the slave & the (presumably overloaded?) master. Can someone
> give me a clearer view of the picture? I know I must be perceiving the
> example incorrectly.
This happens for modification only; reads (which are supposed to
overcome
writes in terms ov load, otherwise don't use Directory Services) are
completed
within the slave, so many slaves allow load balancing (in a typical
scenario
for big organizations noone reads from the master, which is in charge of
replicating changes to a large number of slaves).
Pierangelo.
--
Dr. Pierangelo Masarati | voice: +39 02 2399 8309
Dip. Ing. Aerospaziale | fax: +39 02 2399 8334
Politecnico di Milano |
mailto:pierangelo.masarati@polimi.it
via La Masa 34, 20156 Milano, Italy |
http://www.aero.polimi.it/~masarati