[Samba] Strange DB behaviour

[mathias dufresne]

Hi all,

Weeks ago, testing DB space used by groups I created 3 DC, each containing
120 000 users and having their own domain.
Then I've created groups with random users, each group with the same number
of users (10, 100 and 1000 members). LDIF files always contain 1000 members
(100 groups of 10 users, 10 of 100 members and one group for the last
case). Finally I injected LDIF sequentially, until DB size reached its
limit.

So I abandoned these 3 DCs with an almost full DB, so 4GB each.

Last days I was interesting about tombstoneLifetime, how to change it, how
DB would react to that change etc.

But prior to that I had a try about setting up a passwords to my users.
After few (1000 to 2000) password changes DB has no free space even for a
new password. That should have led me to play with tombstoneLifetime :)

So I set up, on only one DC, a tombstoneLifetime of 1 day. Following that I
launched a "tdbdump DC\=AD,DC\=DOMAIN,DC\=TLD | tdbrestore
DC\=AD,DC\=DOMAIN,DC\=TLD.restored"

The point is resultant file was 2.8GB (2 906 853 376 bytes) rather than 4GB
fully filled.

This was on the the DC with 100 members groups.

Wondering about that behaviour, I changed tombestoneLifetime on the two
other DC then tdbdump | tdbrestore them.

On DC with 1000 members per group the result was identical: 2.1GB for
restored DB (2 220 548 096 bytes).
On last DC with 10 members per group restored database is still 3.7GB (3
935 682 560 bytes).

As I never used ldbdel command on none of these DC I would have expected I
had no deleted objects but according to these tests, it seems some objects
were considered as deleted when adding users to groups.

Is this behaviour really a functionality? (No offence meant in that
question ;)

Cheers,

mathias