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Re: slapadd speed



Hi,

On Fri, Feb 28, 2003 at 02:34:57PM +0100, Russell Coker wrote:

> I am having problems with the speed of slapadd for creating a new LDAP 
> directory from an LDIF file.
> 
> I am using a SMP machine with 2* 1.8GHz P4 Xeon CPUs and 4G of RAM.
> 
> I only have minimal indexing defined as listed below.  The slapadd process 
> takes up 99% CPU time and processes about 1M of data per second, which I 
> think is inadequate for such a system.  Any suggestions on improving 
> performance?
> 
> I've included all relevant slapd.conf settings.  I am using slapd version 
> 2.0.23-6.3 (woody).  I will be happy to back-port the version from unstable 
> if it'll help.
> 
> database        ldbm
> cachesize       100000
> dbcachesize     10000000

I suspect the law of diminishing returns here. Cachesize (in entries) is
a factor 100 above slapd's default, the same for dbcachesize. I have no
idea what their in-memory data structures look like, but they may be
inefficient for larger sizes. 

You may also be suffering from excessive lock contention if you're
pounding it on an SMP box. OpenLDAP isn't known to handle that
particularly well.

Try setting threads and concurrency to 1, and enable dbnolocking.

Lastly, even though the CPU time indicates no I/O seek latency problems,
you may want to experiment enabling dbnosync as well. It can make a
*huge* write throughput difference if you trust your backend storage
enough.

Cheers,


Emile.

-- 
E-Advies / Emile van Bergen   |   emile@e-advies.info
tel. +31 (0)70 3906153        |   http://www.e-advies.info

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