When I write LDIFs to one node like delete user or remove user from
group, we see spikes in authentication latency metrics (what's normally .2 - .5
response time goes up to 15-30 seconds) across all nodes in the cluster at the same time.
I ran mdb_copy -c to compact the LDAP databases. The size went from
2.9G to 140M and the latency problem during inserts went away.
I've noticed the LDAP data.mdb is growing about 25M per day. What
accounts for the growth of free pages?
On Tue, Apr 13, 2021 at 1:32 PM Howard Chu <hyc(a)symas.com> wrote:
> Zetan Drableg wrote:
> > openldap 2.4.57 on 16 core OracleLinux VMs with NVME disk.
> > 8 nodes in n-way multi master configuration, MDB backend, 50k unique DNs.
> > We see about 10,000 auths per minute per node.
> > Under heavy client load, the log shows many "deferring operation:
binding" messages in the same second. slapd is using only 400% cpu (of 1600
> Probably you could increase # of listeners. In a pure Bind-only workload slapd ought
to be able to utilize 100% of all cores.
> > [2021-04-13 19:15:58] connection_input: conn=150474 deferring operation:
> > When I write LDIFs to one node like delete user or remove user from group, we
see spikes in authentication latency metrics (what's normally .2 - .5 second
> > response time goes up to 15-30 seconds) across all nodes in the cluster at the
> > What knobs can be adjusted to allow for more concurrency? It seems like writes
are impacting reads.
> You need more information, like I/O wait %, network % utilization, to identify the
cause of these latency spikes.
> Nobody can suggest what to tune without knowing why the bottleneck occurs.
> -- Howard Chu
> CTO, Symas Corp. http://www.symas.com
> Director, Highland Sun http://highlandsun.com/hyc/
> Chief Architect, OpenLDAP http://www.openldap.org/project/