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.
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).
Franky