[Samba] Size of locking.tdb?

[Alexey Lobanov]

Hi Gerald.

Date sent:      	Wed, 01 Oct 2003 13:41:22 -0500
From:           	"Gerald (Jerry) Carter" <jerry at samba.org>
To:             	Alexey Lobanov <aal at evidence-cpr.com>
Copies to:      	samba at lists.samba.org
Subject:        	Re: [Samba] Size of locking.tdb?

> we never pack TDB's.  You can safely remove the
> tdb after shutdown though.  What size are you seeing?

Great. I know wtf.

Linux 2.4.any, Samba 2.2.any. When TDB's reside on "async" mounted ext2 
partition, locking.tdb size FOLLOWS the number of records. From 25 kilobytes to 
hundreeds of kilobytes, and back. When /var is mounted "sync", the database 
really stays at maximum size (now 548864 bytes after >3000 records at peak). 
"use mmap" does not affect this behavior.

It is difficult for me to say where is the exact bug resides: in Samba or in 
Linux 2.4 kernel. But the name of bug seems to be "non-coherent access".

It is also difficult to say now if "sync" mounting is a sufficient workaround. 
At least, it is not fatal for performance if /var/spool and /var/log are 
mounted separately.

And it is funny that this TDB "packing" which definitely happens at async Linux 
filesystem is not necessary fatal for locking database contents. Looks like in 
this case Samba dies in quite rare set of conditions. Maybe, when the number of 
records falls very quickly from 2000 to 50, "accounting team go home". Maybe 
not.

Thank you!

Alexey