Samba4: LDB size limit and memory leak
abartlet at samba.org
Wed May 27 01:50:39 GMT 2009
On Mon, 2009-05-25 at 09:23 +0200, Marcel Ritter wrote:
> Andrew Bartlett schrieb:
> > On Mon, 2009-05-25 at 08:30 +0200, Marcel Ritter wrote:
> >> Hi,
> Hi Andrew,
> >> I'm running several samba 4 tests at the moment and I found two things,
> >> that may need some attention:
> >> 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:
> > Correct. If a 64 bit varient of TDB were developed, that limit would be
> > removed.
> So TDB is 32-bit only right now?
> In bugzilla I found something about a 64-bit Patch to TDB, but it's quite
> outdated (from 2005):
Moving TDB to a 64 bit database is more about changing the on-disk
format, and making improvements to the internal structure that would
better suit a database of this size.
However, In retrospect, I'm surprised that you found the limit to be a
20,000 users. This seems rather small: We should expect users to only
take up 2k each, with an additional overhead for indexes.
> Any hint what needs to be done to make it 64-bit capable?
> >> The resulting filesize of users.ldb is exactly 4GB + 4096 bytes
> >> (4294971392 bytes)
I think what's happening here is actually that you didn't add all the
users in a single transaction, and as such are hitting up against the
pathological database growth issues we first saw late last year.
I think we need some internal trigger to say 'repack the database' (ie
As a test, can you keep adding records if you call tdbbackup on the
users.ldb (and then replace users.ldb with the backup)?
Andrew Bartlett http://samba.org/~abartlet/
Authentication Developer, Samba Team http://samba.org
Samba Developer, Red Hat Inc. http://redhat.com
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