RE : Log level and performances

[BAILLEUX Benoît FTRD/DMI/CAE <benoit.bailleux@francetelecom.com>]

Thank you for the trick. I'm not very used to play with that kind of tweak, and I didn't know that possibility.
With logfile written in async mode, the throughput is really better.
In the same condition, I had 29 op/s with sync'ed syslog's file. I now have 1890 op/s with async file.

So the results are now :
 - no log              : 2540 op/s (cool !)
 - loglevel=256, sync  : 29   op/s (uh !)
 - loglevel=256, async : 1890 op/s (not bad ...)
 - slapd -d 256        : 2577 op/s (higher than forseen)

Note for Quanah :
For my tests, I use one physical disk for my BDB database, and one *other* for BDB logs and Syslog files.
However, the file produced by the command line :
  ./slapd -d 256 <other options> > ../my_log_file
Is on the disk with the database.

This is why I don't understand why throughput is slightly better (than slapd without any log) when looging to a standard file. But I suppose that it is more related to the system than to OL ...
-- 
BB

-----Message d'origine-----
De : Daniel van Eeden [mailto:daniel@snow.nl] 
Envoyé : vendredi 16 avril 2004 20:20
À : BAILLEUX Benoît FTRD/DMI/CAE
Cc : openldap-software@OpenLDAP.org
Objet : Re: Log level and performances


Most syslog implementations allow logfiles to be written eighter in sync or async mode. What does your's do?

Daniel van Eeden <daniel_e@dds.nl>

On Fri, 2004-04-16 at 10:52, BAILLEUX Benoît FTRD/DMI/CAE wrote:
> Two questiosn about OL performances when logging is activated.
[...]
OpenLDAP 2.1.5, BDB 4.2.50 (data files and log file on separate disks)
[...]
> 
> So I have two questions :
>  - is there a problem with my configuration that makes slapd so slow when it logs to syslog ?
>  - why is the throughput slightly better (and not clearly worst) when OL logs to stdout ?