Re: Slapd running very slow
--On Tuesday, April 21, 2015 11:54 AM -0400 Brian Reichert
<reichert(a)numachi.com> wrote:
On Tue, Apr 21, 2015 at 08:52:29PM +1000, Geoff Swan wrote:
>
> I have an ldap server that appears to slow down significantly even under
> moderate load, and wondered if there were any suggestions as to where to
> look.
>
> Using openldap-2.4.40 with mdb backend, on a dual Xeon (6 cores each)
> server with 128GB ram.
> Linux kernel 3.13, separate ext4 db volume (SAS). Slapd configured with
> 48 threads.
>
> The problem appears that as soon as there are a handful of write
> operations, slapd appears to stall. Binding to the ldap port takes many
> seconds (instead of instant), and the slapd process appear to occupy
> 100% of a single CPU core.
What does your config file look like?
In particular, what does this setting look like for you:
# Threads - four per CPU
threads 8
According to his summary, he's using 48 threads. 4 per CPU/core was a good
rule of thumb with bdb/hdb. So far in playing with back-mdb, it's seemed
closer to 2 per CPU/core for me in benchmarking.
I'd generally advise testing current RE24 out, as there were some
significant issues in 2.4.40 release.
--Quanah
--
Quanah Gibson-Mount
Platform Architect
Zimbra, Inc.
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