Samba4: LDB size limit and memory leak

[tridge at samba.org]

Hi Marcel,

 > 1. LDB size seems to be limited to 4GB (both on i586 and x86_64). I tried
 >     to create a lot of new users using setup/newuser and somewhere in
 > between
 >     20000 and 40000 users, setup/newuser crashes:

yep, this is because tdb (the underlying database) uses 32 bit
offsets. Rusty and I had a chat recently about how we could make it
support 64 bit offsets while retaining backwards compatibility, but it
is unlikely that change will happen any time soon.

You shouldn't have gotten anywhere near the 4G limit with 20k users
though. I've just done some tests, as we seem to use about 8k of disk
space per new user (including all indexing etc). So 40k users should
use about 320M of disk space. 

I've started an experiment to see how much space 20k users takes on my
system. I'll let you know how it goes.

It is very slow to add users or groups btw. Andrew and I started
looking into why this is yesterday. I'll send a separate email about
that.

Cheers, Tridge