Vortragsdetails

Samba clustering

von Volker Lendecke (Samba Team / SerNet GmbH)

Donnerstag, 31.05.2007, Saal 4: Kaiserslautern , 15:00-16:00 Uhr

The CIFS protocol presents some hard challenges for anybody trying to implement a clustered file server based on it. Unix semantics are roughly matched by the NFS protocol family, Windows semantics by the CIFS protocol.

One particular challenge under CIFS is the fact that every open call to a file needs to communicate with the whole cluster because a process can open a file exclusively for itself. This means that every open must look around in the cluster if any conflicting opens have been done.

Several attempts have been made in the past to make Samba cluster-aware in the sense that you can have a shared posix-style file system like GFS, OCFS (even NFS should work) and share CIFS style services from multiple cluster nodes on the same file space. All attempts have failed because they were either providing incorrect semantics or just unusably slow.

In July 2006 we have presented one of these prototypes and we figured out a major flaw in our thinking: The reason why all attempts have been unusably slow is that our assumptions about lock manager consistency requirements have been wrong. For the speed-critical locks we do not need the consistency a database or typical lock manager would provide, we even need to remove all locks a node has held when it died.

Based on this revised view we have designed and partly implemented our own clustered lock manager and are now in the process to include this into main Samba.

This talk will present our cluster requirements in detail and the current status of the lock manager.

Über den Autor Volker Lendecke:

Volker Lendecke war das erste deutsche Mitglied im Samba Team und seit über 10 Jahren aktiv mit der Weiter-Entwicklung von Samba beschäftigt. 1996 gründete er mit 2 Kollegen die SerNet GmbH in Göttingen, die für Samba Consulting, Training und Support anbietet.
Die SerNet Service Network GmbH (SerNet) ist der technologische
Marktführer bei Leistungen rund um die OpenSource-Software SAMBA
und eines der führenden Linux-System-Häuser in Deutschland mit Sitz in
Göttingen und Berlin.
Weitere Informationen über SerNet finden Sie unter www.SerNet.DE.

Weitere Informationen erhältlich unter:
http://SerNet.DE, http://EnterpriseSamba.ORG