If we talk about syslog ..
SuSE (opensuse/SLES) writes local4 in /var/log/localmessages and
/var/log/messages!!
Best way here to write messages in separate file is:
#### part from syslog-ng.conf #####
filter f_ldap { program(slapd);};
#change original lines:
filter f_local { facility(local0, local1, local2, local3, local4,
local5, local6, local7) and not filter(f_ldap); };
filter f_messages { not facility(news, mail) and not
filter(f_iptables) and not filter(f_ldap); };
#
# LDAP in separate file
#
destination ldaplog { file("/var/log/ldap.log"
owner(ldap) group(ldap)); };
log { source(src); filter(f_ldap); destination(ldaplog); };
### end ######
Additionally there is a sync option for syslg-ng. It can be set in the
options { ...} line.
BTW a few other thoughts, who may influence the speed if you turn on
logging...:
* How many ldap requests per second you get on LDAP?
- you can check this via monitor db
~# ldapsearch ... -b"cn=Search,cn=Operations,cn=Monitor" monitorCounter
~# ldapsearch ... -b"cn=Uptime,cn=Time,cn=Monitor" monitoredInfo
then you can calculate the average of your req/s ...
* How is sized your system (especially CPU, RAM, disks, raid,
controller, partitions, ..)
* database size
* Do you use shm_key (takes away IO from your disk)?
We log (level 256) since a short time too, with about (max) 1200 ldap
req/sec and the system and IO is mostly idle :-)
Kindly regards Meike
2012/6/13 Maucci, Cyrille <[email protected]>:
> How does your syslog config look like ?
> Did you prefix the filename with the magic - symbol in order to ask for async
> I/Os on that file?
>
> E.g.
>
> *.info;mail.none;authpriv.none;cron.none
> -/var/log/messages
>
> mail.*
> -/var/log/maillog
>
> local4.*
> -/var/log/slapd.log
>
> Instead of
>
> *.info;mail.none;authpriv.none;cron.none
> /var/log/messages
>
> mail.*
> /var/log/maillog
>
> local4.*
> /var/log/slapd.log
>
> ++Cyrille
>
> Man syslog.conf
> Regular File
> Typically messages are logged to real files. The file has to be
> specified with full
> pathname, beginning with a slash ??/??.
>
> You may prefix each entry with the minus ??-?? sign to omit syncing the
> file after every
> logging. Note that you might lose information if the system
> crashes right behind a
> write attempt. Nevertheless this might give you back some
> performance, especially if
> you run programs that use logging in a very verbose manner.
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of Berend De
> Schouwer
> Sent: Wednesday, June 13, 2012 12:28 PM
> To: [email protected]
> Subject: loglevel expected performance impact
>
> I'm running some 2.4.23 servers, and I've encountered some slowdown on
> loglevel other than 0. Even 256 (stats; recommended) impacts about a 4x
> slowdown on queries. Logging is to syslog.
>
> Running ldapsearch slows from 0.005-0.010 seconds to about 0.030-0.040
> seconds; and that includes loading the binary. That's from localhost to
> remove potential DNS lookups.
>
> I stumbled across this when logging was wrong, and the slowdown was 100x.
>
> I'm aware that 2.4.23 isn't the latest version. I'm also quite happy, for
> now, to run loglevel 0.
>
> I'm wondering if this is the expected behaviour, given that it's the
> recommended configuration. Or should I go dig to find the slowdown?
>
> (I did check the indexes, and db_stats, etc. All seems fine.)
>
> I apologise for the disclaimer,
> Berend
>
>
>
>
>
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