CTDB internals

Christopher R. Hertel crh at ubiqx.mn.org
Thu Nov 1 22:28:20 MDT 2012

Amitay, Obnox, et. al.,

I just want to make sure that I've got this right...

Reviewing Michael's tutoral, given in 2009 at SambaXP, here's what I get:

* The underlying tables are all TDB tables.

* These TDB tables are of three types:
  1) Persistent
  2) Normal ("volatile")
  3) Recovery

I think I generally understand how these work.  I have some questions about
the sequence of events when writing to a Persistent TDB, but those can wait.

My immediate questions are:

Q: Is the CTDB_RECOVERY_LOCK file the only tdb file that will be stored on
   shared disk and concurrently accessed by multiple nodes?

Q: For the other two types (Persistent and Normal), is the ctdbd daemon
   the only reader/writer to the local TDBs?  For Normal LTDBs in
   particular, is fcntl byte-range locking used to manage access in any


Chris -)-----

"Implementing CIFS - the Common Internet FileSystem" ISBN: 013047116X
Samba Team -- http://www.samba.org/     -)-----   Christopher R. Hertel
jCIFS Team -- http://jcifs.samba.org/   -)-----   ubiqx development, uninq.
ubiqx Team -- http://www.ubiqx.org/     -)-----   crh at ubiqx.mn.org
OnLineBook -- http://ubiqx.org/cifs/    -)-----   crh at ubiqx.org

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