What is the mutex.tdb files purpose?

[Chavez, James R.]

Hello,
Is it possible that someone can explain the significance and purpose of
the mutex.tdb file?

Also I want to remove and readd my box to the domain.. Is it not a good
idea to delete all of my .tdb files in the LOCK directory which is
/var/lib/samba? 

Also I was reading on the samba website that it is good practice to back
up the tdb files with tdbbackup before restarting smbd and nmbd. However
I cannot locate the tdbbackup utility.

Thank you
James 
[2009/01/21 07:08:35,  1] lib/util_tdb.c:tdb_wrap_log(886)
  tdb(/var/lib/samba/mutex.tdb): tdb_lock failed on list 12 ltype=1
(Interrupted system call)
[2009/01/21 07:08:35,  0]
lib/util_tdb.c:tdb_chainlock_with_timeout_internal(91)
  tdb_chainlock_with_timeout_internal: alarm (10) timed out for key
EXAMPLEDC.EXAMPLE.CORP in tdb /var/lib/samba/mutex.tdb
[2009/01/21 07:08:35,  1] lib/server_mutex.c:grab_named_mutex(71)
  Could not get the lock for EXAMPLEDC.EXAMPLE.CORP

  check_ntlm_password:  Authentication for user [some_user] ->
[some_user] FAILED with error NT_STATUS_NO_LOGON_SERVERS
[2009/01/21 07:09:09,  1] lib/util_tdb.c:tdb_wrap_log(886)
  tdb(/var/lib/samba/mutex.tdb): tdb_lock failed on list 12 ltype=1
(Interrupted system call)


CONFIDENTIALITY
This e-mail message and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail message, you are hereby notified that any dissemination, distribution or copying of this e-mail message, and any attachments thereto, is strictly prohibited.  If you have received this e-mail message in error, please immediately notify the sender and permanently delete the original and any copies of this email and any prints thereof.
ABSENT AN EXPRESS STATEMENT TO THE CONTRARY HEREINABOVE, THIS E-MAIL IS NOT INTENDED AS A SUBSTITUTE FOR A WRITING.  Notwithstanding the Uniform Electronic Transactions Act or the applicability of any other law of similar substance and effect, absent an express statement to the contrary hereinabove, this e-mail message its contents, and any attachments hereto are not intended to represent an offer or acceptance to enter into a contract and are not otherwise intended to bind the sender, Sanmina-SCI Corporation (or any of its subsidiaries), or any other person or entity.