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Re: sanity check on updating from HDB backend to MDB
On Tue, Aug 12, 2014 at 02:04:20PM -0400, Brian Reichert wrote:
> On Tue, Aug 12, 2014 at 11:12:51AM -0700, Howard Chu wrote:
> > While that search is running you should see slapd at 100% CPU. If not, then
> > something in your system is throttling your connection.
> And it is not at 100%. 'top' shows slapd on this host is only at ~50%.
> I'll review the 'threads' setting.
The 'ldap' user has no system limits set on it:
# setuidgid ldap sh -c ulimit -a
I have 2 CPUs with 4 cores each:
# grep "^physical id" /proc/cpuinfo | sort -u | wc -l
# grep "^cpu cores" /proc/cpuinfo | sort -u
cpu cores : 4
This page recommends:
This value should generally be a function of the number of "real"
cores on the system, for example on a server with 2 CPUs with one
core each, set this to 8, or 4 threads per real core.
Assuming 'real core' == CPU, in my case, I think this should be 8
(4 * 2 physical CPUs). Is that correct?
It was set to 32 (I have no idea why), and 'top' showed ~50%.
When I changed threads to '8', my query times dropped to ~22 seconds,
which is _much_ better than the 175 I was seeing.
'top' still shows slapd only using %50, so I hazard that it keeps
to one CPU. Is that a valid assumption?
Could this mdb database perform better? It's outperforming my bdb
backend by %25, which isn't too shabby, but I'm curious if this
sort of performance increase is typical...
Brian Reichert <email@example.com>
BSD admin/developer at large