Re: Open LDAP Load Handling

[Terry Lambert <terry@whistle.com>]

Prashant K.S wrote:
>     I am using openldap for authentication of the
> users on a mail server. Actually our setup consists of
> 4 mail servers. The total number of users using our
> system are around 1 million. Now basically some times
> due to the heavy load slapd dies or goes in a defunct
> state.Is OpenLdap not capable of handling loads of
> some 5000-10000 hits/sec. If Yes please tell me if any
> configuration needs to be changed.

You don't say anything about your OS or setup.

If you are running on DOS on an 8 MHz PC-AT using KA9Q
over your local ametuer radio repeater for your network
connectivity, I rather suspect your load is too high for
your hardware...

The failures you are seeing should not be occurring, but
with absolutely no context, we'll have a hard time with
providing any useful advice.

Normally, LDAP load balancing is done by setting up a
number of slaves and a stealth master.  Like DNS, this
permits the master to handle only writes (by way of a
referral to the client from the slaves), and clients
all run against the slaves, as the published site LDAP
servers (e.g. publication via DNS SRV records).  This
lets you throw more hardware at the load problem, until
you reach the write-load-limit.

Since most traffic is supposed to be read traffic, or
you are supposed to be using different technology, this
generally works very well (how often does your name or
phone number or password change?).


If you wanted to give us more information about your
exact setup, and what you mean by "dies" and "defunct
state", we could probably help you out with your basic
problem, which is probably not related to load, unless
you are using kernel threads on Solaris or Linux, and
just have a lot of clients, and so are running out of
system resources, in which case: don't.


-- Terry Lambert
-- Whistle Communications, Inc., an I.B.M. Company
-- terry@whistle.com
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