samba - Nov 2008 - winbindd consuming 99% CPU

Hi All,

We are currently caught up in a weird situation while using samba 3.0.28. There
is a requirement from the customer that we should support ADS with 64000
objects. When we implemented the feature, we found couple of things mentioned
below:

1. After joining ADS with 64k users, samba takes around 20 - 25 min to populate
idmap_cache.tdb and winbindd_cache.tdb This is because we haven't turned of
enumeration and we would be fixing it for next maintenance release of the NAS
product.

2.  We periodically check the quota state of all the users using repquota
command. It refers to /etc/nsswitch.conf for mapping user ids to names. And
winbindd inherently should look for its cache as it is populated completely to
do the conversion.

But we observed that every time the repquota command is invoked, winbindd starts
consuming 98% of CPU. It fetches the info from ADS and not from local cache. So
we are wondering why it doesn't make use of local cache for mapping the ids
to names?

Here is the system info:

Kernel : 2.6.18
Samba - 3.0.28a
arch - mips 1GHz

All your help is really appreciated. 

Thanks 

Sagar

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Sagar Borikar wrote:
> Hi All,
> 
> We are currently caught up in a weird situation while using samba 
> 3.0.28. There is a requirement from the customer that we should support
> ADS with 64000 objects. When we implemented the feature, we found
> couple of things mentioned below:
> 
> 1. After joining ADS with 64k users, samba takes around 20 - 25 min 
> to populate idmap_cache.tdb and winbindd_cache.tdb This is because
> we haven't turned of enumeration and we would be fixing it for
> next maintenance release of the NAS product.
> 
> 2.  We periodically check the quota state of all the users 
> using repquota command. It refers to /etc/nsswitch.conf for mapping
> user ids to names. And winbindd inherently should look for its
> cache as it is populated completely to do the conversion.
> 
> But we observed that every time the repquota command is invoked, 
> winbindd starts consuming 98% of CPU. It fetches the info from
> ADS and not from local cache. So we are wondering why it doesn't
> make use of local cache for mapping the ids to names?
Sagar,

The enumeration is killing you performance wise.  As a workaround
you could try in creasing the "winbind cache time" to something like
1 or 2 hours.  But there is a constant struggle between cache times
and accuracy.




cheers, jerry
- --
====================================================================Samba       
------- http://www.samba.org
Likewise Software          ---------  http://www.likewisesoftware.com
"What man is a man who does not make the world better?"      --Balian
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.6 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iD8DBQFJEatJIR7qMdg1EfYRAhmyAJ9CcrZLclYZ+P8q0hHI7EsUt7kRKwCg0km4
LWFcHLKbEfl8UMYnd4JWqpA=3KW6
-----END PGP SIGNATURE-----