[Ocfs2-devel] Please help me in getting OCFS2 design doc.
Sum Sha
sumsha.matrixreloaded at gmail.com
Wed May 3 06:18:14 CDT 2006
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 at 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
> > <mailto:ocfs2-devel-request at oss.oracle.com>* <
> > 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 at oracle.com
> > <mailto:Sunil.Mushran at oracle.com>>
> > Subject: Re: [Ocfs2-devel] Please help me in getting OCFS2 design
> > doc.
> > To: Sum Sha <sumsha.matrixreloaded at gmail.com
> > <mailto:sumsha.matrixreloaded at gmail.com>>
> > Cc: ocfs2-devel at oss.oracle.com <mailto:ocfs2-devel at oss.oracle.com>
> > Message-ID: < 4450F95B.8000704 at oracle.com
> > <mailto:4450F95B.8000704 at 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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