On Fri, Dec 08, 2017 at 11:57:23AM +0100, Franky Van Liedekerke wrote:
Op Vrijdag, 08-12-2017 om 11:34 schreef Sumit Bose:
> On Fri, Dec 08, 2017 at 11:10:49AM +0100, Franky Van Liedekerke wrote:
> > Before opening a bug report, I wanted to discuss a new issue here.
> >
> > I have ldap users that are in 1500 groups (yeah, I know ... not my choice
either), ldap is using rfc2307 scheme (openldap, redhat EL7).
> > Now, when connecting sssd to this ldap server, I've already set
enumeration=false, and also ignore_group_members=true (performance ...).
> > However, with ignore_group_members=true, I'm getting this in the
sssd_nss.log when doing a 'groups <userid>" command:
> >
> > [sssd[nss]] [sss_mc_find_record] (0x0010): Corrupted fastcache. name_ptr value
is 16
> >
> > (once when the cache is empty, and after that once or twice per
groups-request).
> > I also see this in /var/log/messages (related of course):
> >
> > sssd[nss]: Stored copy of corrupted mmap cache in file
'/var/lib/sss/mc/group_corrupted#012'
> >
> > As a result, this prevents the use of the sssd fast cache, so group requests at
best take 5.5 seconds.
> > Now this problem happens 95% of the cases (which leads me to believe it is a
timing bug), but when I set ignore_group_members=false, this is not happening (and when
groups are ok in the fast cache: 0,03 secs response time).
> >
> > Ideas? Hints? Or should I just go and open a bug report? Is there a real
performance drawback to setting ignore_group_members=false?
>
> There is already a BZ
>
https://bugzilla.redhat.com/show_bug.cgi?id=1490120.
>
> I think in your setup (plain LDAP with rfc2307) the performance loss
> when using ignore_group_members=false (the default) should be
> acceptable.
>
> bye,
> Sumit
Unfortunately I can't view the content of that BZ (no access, I'm searching for
an account at my current company that does), so any insight/summary on that one would be
appreciated.
Here is the related upstream ticket
https://pagure.io/SSSD/sssd/issue/3571.
Fun fact just for info: we had to switch to rfc2307 (from 2307bis)
because of another bug in sssd that ignores the setting to not do nested group searches,
which resulted in a huge amount of extra ldap searches per user (1 per group).
Did you open a ticket about this?
bye,
Sumit
>
> Franky
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