From owner-freebsd-hackers Thu Sep 18 05:29:43 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id FAA02912 for hackers-outgoing; Thu, 18 Sep 1997 05:29:43 -0700 (PDT) Received: from ns.ineco.ryazan.su (root@ns.ineco.ryazan.su [194.58.169.17]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id FAA02801 for ; Thu, 18 Sep 1997 05:26:18 -0700 (PDT) Received: from dialup.galion.ryazan.su (dialup.galion.ryazan.su [194.58.169.238]) by ns.ineco.ryazan.su (8.7.5.R.ML.S/Relcom-2A) with ESMTP id QAA09946 for ;Thu, 18 Sep 1997 16:25:09 +0400 Received: from mutant.galion.ryazan.su by server.galion.ryazan.su with SMTP (Microsoft Exchange Internet Mail Service Version 5.0.1457.7) id T1MQBVKY; Thu, 18 Sep 1997 16:24:08 +0400 Received: from localhost (romanp@localhost.galion.ryazan.su [127.0.0.1]) by mutant.galion.ryazan.su (8.8.5.R.S/Relcom-2A) with SMTP id QAA00762 ;Thu, 18 Sep 1997 16:25:40 +0400 (MSD) Date: Thu, 18 Sep 1997 16:25:39 +0400 (MSD) From: "Roman V. Palagin" To: Simon Shapiro cc: FreeBSD-Hackers@FreeBSD.ORG Subject: Re: Distributed Lock Manager on FreeBSD In-Reply-To: Message-ID: Organization: Systems Integration "RIGHT" MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk WoW!! I think this is great project. Can you give me more information? ------------------------------------------------------------------------------- Roman V. Palagin Systems Integrator "RIGHT" Network Administrator http://www.galion.ryazan.su Internet Mail: romanp@mutant.galion.ryazan.su Tel: +7 (0912) 725638 ------------------------------------------------------------------------------- On Tue, 16 Sep 1997, Simon Shapiro wrote: > We are putting the finishing touches on a true general purpose distributed > lock manager for FreeBSD. This message is a solicitation for interest. If > I receive enough interest in it I will start a chain of discussions on the > subject and solicit core review for inclusion in FreeBSD. This may not be > easy as some of my management would like to keep it proprietary. > > To illustrate, an Oracle equivalent (subset, really) had a cost of over > $250,000 for the source and about 1/5 for binary. > > > VERY BRIEF SUMMARY: > > DLM is a method by which cooperating processes on different machines (even > different operating systems) can inform each other of interest in a named > object. Just like a database lock manager, or a file system lock manager, > but with the ability to span hosts in real time. > > Some highlight of this DLM: > > * Kernel implementation; All the locking logic is in the O/S kernel, not > in userspace. > > * Multi-state, hirerchial lock with up to 32 states per lock. > > * Conflict resolution built in; Caller can specify which states to > consider in conflict analysis. > > * Conflict Blocking; Caller can specify which conflict to block on. > > * Programmable conflict block; Allows caller to specify how long to wait. > > * Multiple-locking. Individual states can accumulate; A locker can > specify that multiple ``read'' locks are permitted. the DLM will > track how many are actually applied. > > * Remote Locking; A call to the local DLM agent for locking a remote > resource is automatically proxied. > > * Shared Locking; If a resource is shared, the DLM will apply both local > and remote lock and automatically/instantly resolve deadlocks. > > * Multi-path; Each resource can have its own data path (TCP/IP, SCSI, > RCS-232, etc.) UDP support is running, SCSI support via DPT is > forthcoming. > > * External resource management; The mapping of resources is external to > the locking agent. > > * Distributed; There is no central locking authority, although you can > easily create one via resource configuration. > > + What is it good for? We are using it to build our non-stop RDBMS server, > which is composed of a group of FreeBSD machines tied to a single disk > farm. The RDBMS is PgSQL with the lock manager replaced with the DLM and > the storage manager replaced with the DBFS/DIO module I am still working > on. > > If any of this is of any interest to any of you, drop me a line. Please > try to do so soon , so I can decide how to document the thing. > > > > --- > > > Sincerely Yours, (Sent on 16-Sep-97, 19:18:09 > by XF-Mail) > > Simon Shapiro Atlas Telecom > Senior Architect 14355 SW Allen Blvd., Suite 130 Beaverton OR 97005 > Shimon@i-Connect.Net Voice: 503.643.5559, Emergency: 503.799.2313 > >