Re: openldap server load serving sendmail access map

[Igor Brezac <igor@ipass.net>]

Curtis,

This is proly an OT post, so you might get a better response on
news:comp.mail.sendmail or other sendmail related mailing lists.

Having said that, I am also interested in this subject so hopefully Kurt
will not cut our discuission short.  ;)  In my limited research, I found
that the "access" query is not an issue, but rather an amount of queries
needed to process one email delivery.  If I remember correctly, sendmail
will run up to 50 'access' queries for each message going thru sendmail.
So depending on your email volume, your LDAP server will need to be able
to run hunderds if not thousdands of queries per second.  I will work
toward reducing the amount of LDAP queries needed per email transaction.

-Igor

On Tue, 22 Oct 2002, curtis wrote:

>
> We are looking at migrating to LDAP as part of the architecture of our
> hosted e-mail product.
>
> As a test we started by making the access map served by LDAP.  The
> sendmail gateway is running on an Ultra 2 w/300MHZ proc with sendmail
> 8.12.5 compiled with openldap.  The LDAP server is a Ultra 2 w/dual 300MHZ
> procs and also runs PostgreSQL (with minimal load).
>
> Even after "optimizing" the access map query for simplicity (which lowered
> the load), slapd is consuming roughly 50% of the CPU.  The query has been
> simplified to:
>
> Kaccess ldap -T<TMPF> -1 -v sendmailMTAMapValue -k
> (&(sendmailMTAMapName=access)(sendmailMTAKey=%0))
>
> The prior query which consumed even more CPU (but not substantially more) was:
>
> Kaccess ldap -T<TMPF> -1 -v sendmailMTAMapValue -k
> (&(objectClass=sendmailMTAMapObject)(|(sendmailMTACluster=${sendmailMTACluster})
> (sendmailMTAHost=$j))(sendmailMTAMapName=access)(sendmailMTAKey=%0))
>
> The load on the sendmail server averages around 100 processes.  The CPU
> load on the LDAP server is more than that of the sendmail server.  While
> I would expect more overhead for the LDAP solution based on the flexibility
> and all, it seems disproportionately high.
>
> The load seemed slightly better when I bound slapd to one processor, although
> that could have been a slight difference of load between the unbound test
> and the bound test.
>
> Any input would be appreciated as an LDAP architecture would solve some
> headaches we have as well as lend itself to an overall better architecture.
>
> Thanks in advance,
>
>   -- Curt
>
>
> Curtis Wilbar
> Virtual E-Services Network, Inc.
> curtis@vesn.com
>
>
>

-- 
Igor