CTDB - the 'Mainz' plan for clustered Samba

Andrew Tridgell tridge at au1.ibm.com
Tue Oct 3 11:11:52 GMT 2006


 > I drew first diagrams about Samba & Clustering and placed them at the
 > wiki page http://wiki.samba.org/index.php/Samba_%26_Clustering. Please,
 > check if I didn't understand your ideas.


A couple of minor things:

 - some of the steps listed in the diagrams will be skipped in the
   average case. I should explain more about the way that nodes will
   cache DMASTER lookups. Basically a node can agressively cache any
   DMASTER lookup it does. It doesn't matter if the cache goes stale,
   as a old cache entry will trigger an error which will cause a new
   lookup of the DMASTER from the LMASTER.

 - I expect that the 'conditional append' and 'remove trigger'
   operations will be the most common operations, not the 'fetch'
   operation. It basically allows us to combine a
   lock/fetch/modify/write/unlock sequence into a single round
   trip. This builds upon Volkers fetch_and_lock method which reduced
   it to two round trips.

Cheers, Tridge

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