[Ocfs2-users] CDSL .vs. Bind mounts?

[John McNulty]

Ah I get it.  It's the combination of bind mounts and symbolic  
links.   So if I want to have /home in a cluster filesystem but have a  
unique /home/oracle/.bashrc for each node in the cluster I can do  
something like this:

On node1:

#  cd /home
#  mkdir -p cluster/node1/oracle  cluster/node2/oracle  cluster/local/ 
oracle
#  chown oracle.dba  cluster/node1/oracle  cluster/node2/oracle   
cluster/local/oracle
#  mount --bind /home/cluster/node1  /home/cluster/local
#  cd  oracle
#  cp  .bashrc  /home/cluster/node1/oracle
#  cp  .bashrc  /home/cluster/node2/oracle
#  rm  .bashrc
#  ln -s /home/cluster/local/oracle/.bashrc  .bashrc
#  vim .bashrc

On node2:

#  mount --bind /home/cluster/node2  /home/cluster/local
#  cd /home/oracle
#  vim .bashrc

And personalize each one accordingly.

Nice!

John


On 23 Sep 2009, at 11:27, Marc Grimme wrote:

> As we are making shareing the "/"-Filesystem among multiple nodes we  
> are using
> CDSL as part of the concept.
> What we do is we create
> <mount-point>/cluster/<nodeid>
> <mount-point>/cdsl.local -> /cluster/nodeid (via bind mount)
>
> Then say you would like to make /opt/application/file1 hostdependent  
> do the
> following
> mkdir -p /cluster/cdsl/[1-n]/$(dirname /opt/application/file)
> cp -a
> <mount-point>/opt/application/file /cluster/cdsl/[1-n]/$(dirname / 
> opt/application/file)
> ln -s <mount-point>/opt/application/file
> <mount-point>/cdsl.local/opt/application/file
>
> That's it and it works pretty well.
> Hope this helps.
> This concept keeps all file that are hostdep and reshared
> in /cluster/cdsl/.. .
> Regards
> Marc.
>
> BTW: We've also developed tools to manage those cdsls.
> Those are based on the syntax for the Tru64-Cluster cdsl tools.
> i.e. com-mkcdsl -a /opt/application/file1 (-a => hostdependent)
>
> See www.open-sharedroot.org.
> On Tuesday 22 September 2009 23:15:07 John McNulty wrote:
>> I'm puzzled.  Coming from a Tru64/TruCluster background I know CDSL's
>> well, but have never used bind mounts.  From reading about them it
>> looks to me like:
>>
>>     a CDSL = [one] file that points to [many] files, but
>>     a bind mount = [many] mount points that originate from [one]
>>
>> Not only is the one to many relationship of a bind mount the opposite
>> of a CDSL, but it's not possible to replace  [for example] a CDSL
>> like /etc/application.conf by mounting something on top of it.
>>
>> How is this supposed to work?
>>
>> Rgds,
>>
>> John
>>
>> On 17 Sep 2009, at 16:33, David Johle wrote:
>>> At 02:00 PM 5/5/2009, ocfs2-users-request at oracle.com wrote:
>>>>       The mainline linux kernel developers have decided that CDSLs
>>>> are
>>>> not something they will accept.  As such, ocfs2 in mainline does  
>>>> not
>>>> support them, and production ocfs2 1.4 and later do not either.
>>>>       The recommended solution from the kernel developers is bind
>>>> mounts.  You can set those up on your own system via startup  
>>>> scripts.
>>>>
>>>> Joel Becker
>>>> Principal Software Developer
>>>> Oracle
>>>> E-mail: joel.becker at oracle.com
>>>> Phone: (650) 506-8127
>>>
>>> So here I am once again trying to eliminate the use of CDSLs so that
>>> I can upgrade past 1.2.x, and I'm finding myself stuck.
>>>
>>> I have made use of bind mounts for entire directories that were
>>> node-specific via CDSL.  However, I have yet to find an alternative
>>> for a CDSL that points at a single file.  I've been re-working
>>> applications configs and all to reduce depency on CDSL and/or bind
>>> mounts, but I've gotten down to only TWO files left which use a
>>> CDSL.  And, due to the nature of the application and configuration
>>> file I cannot figure a way around the CDSL.
>>>
>>> Has anyone else gone through this process of getting away from
>>> specific file CDSLs?  If so, what did you do?
>>>
>>> _______________________________________________
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>>> Ocfs2-users at oss.oracle.com
>>> http://oss.oracle.com/mailman/listinfo/ocfs2-users
>>
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>
>
>
> -- 
> Marc Grimme
>
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