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Re: (ITS#8669) Slapd service becomes unresponsive intermittently


We are running the Berkley DB back-end, =B3back-bdb=B2 in the slapd.conf file.

Our server vendor did the upgrade to version 2.4.39 last year in April. In
asking them about upgrading to a newer version, as a potential fix, I was
told the last version in the RHEL repository that they can upgrade to is
2.4.40. I=B9m not certain that our vendor will support our choice to upgrade
to a newer version than what RHEL provides them in the repository, but if
it will fix our problem, I=B9ll have to push the envelope on that matter.

Were there any known fragmentation issues with back-bdb in the 2.4.39
version that could also be causing these pauses?

Initially, when we started having problems with the pausing, the server
would go offline for about 15-20 minutes then recover itself. The
developers had initially set the idletimeout to 8 minutes (480) and we
also noted that rsyslogd was constantly logging entries about the slapd
service, which stated that the the PID of the slapd service was losing
messages to the log due to rate-limiting. Rate limiting was enabled by
default for rsyslog so our vendor recommended to turn this off. At the
same time, when they did this we scaled back the idletimeout period to 5
minutes (300). This seemed to aggravated the problem. With the original
settings, we would encounter this =B3pause=B2 problem maybe once or twice in a
3 month period, and now after these changes were made we=B9re seeing this
more frequently, although when it does pause it seems to only be for about
10 minutes, where it was pausing for 15-20 before. We currently have the
logging level set to the recommended =B3256=B2, but we=B9re considering lowing
the logging level also.

Is it possible we have the idletimeout set too high and it should be
lowered? I=B9m wondering if there is some sweet-spot value for this
particular setting.

The reason our developers had it set so high was because, in the past they
used to run some really long reports. I=B9m pretty sure they do not run
these any longer.

I appreciate your feedback.


On 6/6/17, 6:57 PM, "Quanah Gibson-Mount" <quanah@symas.com> wrote:

>--On Tuesday, June 06, 2017 8:39 PM +0000 jmestrada69@gmail.com wrote:
>> Is there a known bug with this version that could be causing this?
>Hard to say.  It is 3.5 years old and 6 releases behind.  You don't state
>which backend you're using, which may be relevant as well.  There were
>known fragmentation issues with back-mdb in that release, for example,
>could cause extensive pauses.  Without knowing significantly more about
>your system configuration, there's only a ton of speculation that can
>You may want to see about using the builds from the LTB project
>(<http://ltb-project.org/wiki/download#openldap>), or if you require
>support for your deployment, Symas (my employer) offers packaged builds
>various support options.
>Quanah Gibson-Mount
>Product Architect
>Symas Corporation
>Packaged, certified, and supported LDAP solutions powered by OpenLDAP: