[Samba] Speeding up 'getent passwd' with winbindd on AD
Gautier, B (Bob)
Bob.Gautier at rabobank.com
Thu May 4 13:33:05 GMT 2006
I am working on a Linux-AD integration using winbindd in security=ads
mode with idmap=ad.
Everything is basically working, but the performance of user (and group)
enumeration has been very poor and I am almost at the stage where I ask
my users if they can live without it, though I would prefer not to.
In my test environment, I have about 8500 users in AD, of which
currently only about 10 have the necessary attributes to make them valid
Linux users. When I try to enumerate the users, I notice that winbindd
gets the list of *all* users in AD, and then (in idmap_ad) it makes an
LDAP query per-user for the SFU attributes (e.g. uidNumber etc). Most
of those queries fail, of course.
By changing the LDAP filter (in winbindd_ads.c, function
query_user_list) from "(objectClass=user)" to (for example)
"(&(objectClass=user)(uidNumber=*))", i.e. by asking *only* for users
that have a uidNumber attribute, I have reduced a response time of 4
minutes for 'getent passwd' down to only 6 seconds.
I'd really like to see a change like this go into Samba, but I realise
the new filter isn't compatible with other idmap backends, and so at
best it needs to be optional. Currently I have a patch which applies
the filter only if 'winbind nss info = sfu' in in effect.
I'm posting this here to get feedback: should I file an enhancement
request in Bugzilla, refine the fix somehow first, or forget it
This email (including any attachments to it) is confidential, legally privileged, subject to copyright and is sent for the personal attention of the intended recipient only. If you have received this email in error, please advise us immediately and delete it. You are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited. Although we have taken reasonable precautions to ensure no viruses are present in this email, we cannot accept responsibility for any loss or damage arising from the viruses in this email or attachments. We exclude any liability for the content of this email, or for the consequences of any actions taken on the basis of the information provided in this email or its attachments, unless that information is subsequently confirmed in writing. If this email contains an offer, that should be considered as an invitation to treat.
More information about the samba