[Ocfs2-devel] Please help me in getting OCFS2 design doc.

[Sunil Mushran <Sunil.Mushran@oracle.com>]

The faq has been updated with descriptions of the various threads.

ASM and OCFS2 have nothing in common. Volumes can either
be OCFS2 or part of an ASM disk group but not both.

Sum Sha wrote:
> Thanks a bunch for the reply, which could give me some inside view 
> without going through the code. It'd have been great, if you had 
> written a doc mentioning all these details and rolled it out :)
>
> There are some ocfs2_wq, ocfs2_vote and ocfs2_cmt threads created, 
> when I mount a shared volume. Any details about them?
>
> Moreover, as you said that OCFS2 has shorter timings than that of CRS, 
> so do we solely depend on this fact (shorter timings) to prevent CRS 
> from intruding into racing during crash and split-brain situations. I 
> was just trying to understand how it works. I think CRS misscount is 
> 60 for Linux. Do we believe that by this time, OCFS2 would have taken 
> all the decisions and completed the recovery before CRS (or rather 
> CSSD) starts its ejection mechanism? Without ASM, how do we ensure 
> that underlying Volume Manager's recovery has been completed before 
> OCFS2 starts its recovery. And how does it happen when we use ASM?
>
> Sorry, if I am going out of the context, but just wanted to get some 
> information how they co-ordinate.
>
> Thanks.
> Sumsha.
> On 5/2/06, *Sunil Mushran* <Sunil.Mushran@oracle.com 
> <mailto:Sunil.Mushran@oracle.com>> wrote:
>
>     The modules don't map one on one. The idea is to keep the
>     number of modules at a minimum while retaining some sense
>     modularity.
>
>     For e.g., ocfs2_nodemanager.ko  encompasses nm, heartbeat and net/tcp.
>
>     The various kernel/worker threads may change over time.
>     For e.g., we added dlm_wq in the last drop. Again, the idea is to
>     keep the threads at a minimum while still functioning. :)
>
>     o2cb (ocfs2 cluster stack) and crs have nothing in common. No, they
>     don't talk to each other. o2cb is almost entirely implemented in
>     kernel
>     space while crs in userspace.
>
>     ocfs2 default timings are much shorter than crs. The idea is to
>     recover
>     dead nodes before crs times out.
>
>     Sum Sha wrote:
>     > Thanks Sunil for this information. I tried going through the docs
>     > mentioned there, they are useful, but there are details which I
>     wanted
>     > for my  learning purpose which are not in those docs. It would be
>     > great if anyone can share any good doc mentioning details about
>     > Clustering Services which OCFS2 uses. I know that clustering
>     services
>     > which OCFS2 uses has the following components:
>     >
>     > 1. Node manager
>     > 2. Heartbeat module
>     > 3. TCP Protocol module
>     > 4. DLM
>     >
>     > But once I install and configure OCFS2, I can see the following
>     > modules getting loaded:
>     >
>     > 1. configfs (with filesystem mounted)
>     > 2. ocfs2_nodemanger
>     > 3. ocfs2_dlm
>     > 4. ocfs2_dlmfs (with filesystem mounted)
>     >
>     > and the following threads created:
>     > 1. ocfs2_wq (perhaps it's the kernel worker thread)
>     > 2. ocfs2_vote (for voting requests. Is this the listener thread?)
>     > 3. ocfs2_cmt (perhaps this is the node monitoring thread?)
>     >
>     > Can't think of OCFS2 in 10g environment where we have another
>     required
>     > and reliable clustering service CRS (with 10g) running and managing
>     > Oracle's resources. Do CRS and OCFS's clustering services
>     co-ordinate
>     > in some manner or do they take actions independently on their own
>     > during crash and other conditions?
>     >
>     > Any help would be highly appreciated!!
>     >
>     > Thanks.
>     > Sumsha.
>     >
>     > On 4/28/06, *ocfs2-devel-request at oss.oracle.com
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>     >        1. Re: Please help me in getting OCFS2 design doc. (Sunil
>     Mushran)
>     >
>     >
>     >    
>     ----------------------------------------------------------------------
>     >
>     >
>     >     Message: 1
>     >     Date: Thu, 27 Apr 2006 10:03:23 -0700
>     >     From: Sunil Mushran < Sunil.Mushran@oracle.com
>     <mailto:Sunil.Mushran@oracle.com>
>     >     <mailto:Sunil.Mushran@oracle.com
>     <mailto:Sunil.Mushran@oracle.com>>>
>     >     Subject: Re: [Ocfs2-devel] Please help me in getting OCFS2
>     design
>     >     doc.
>     >     To: Sum Sha <sumsha.matrixreloaded@gmail.com
>     <mailto:sumsha.matrixreloaded@gmail.com>
>     >     <mailto:sumsha.matrixreloaded@gmail.com
>     <mailto:sumsha.matrixreloaded@gmail.com>>>
>     >     Cc: ocfs2-devel at oss.oracle.com
>     <mailto:ocfs2-devel@oss.oracle.com>
>     <mailto:ocfs2-devel@oss.oracle.com
>     <mailto:ocfs2-devel@oss.oracle.com>>
>     >     Message-ID: < 4450F95B.8000704@oracle.com
>     <mailto:4450F95B.8000704@oracle.com>
>     >     <mailto:4450F95B.8000704@oracle.com
>     <mailto:4450F95B.8000704@oracle.com>>>
>     >     Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>     >
>     >     Look into docs in ocfs2 projects page. While there
>     >     is no design doc, there is a presentation which lists
>     >     out the changes.
>     >
>     >     http://oss.oracle.com/projects/ocfs2/documentation/
>     >
>     >     Sum Sha wrote:
>     >     > Hi all,
>     >     > Could someone point me to design doc for OCFS2? I could
>     get OCFS
>     >     V-1
>     >     > design doc, but could not find any design doc for OCFS2. I
>     read
>     >     > somewhere that OCFS2 has got lots of design changes as
>     comapared to
>     >     > OCFS1.
>     >     >
>     >     > Thanks in advance.
>     >     >
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