Re: Hi-AV cluster disk ownership?

[Ramachandra Pai <linuxram@yahoo.com>]

Well I understand that you can use hardware features
like zoning, or lun masking etc.  This will ensure
that a node sees only the disk it is supposed to see.

But in an all encompassing paradigm like that of
linux, where disks of all kinds reside; some
supporting hardware features, some too naive; is there
any solution that can meet these requirement?

If we assume no hardware support, disk labeling could
be a solution.  But if you do that; so many issues 
pop up like:

1. Is there any location on the disk where that
information can be kept satisfying the metadata
placement rules of the various partitioning schemes?
2. If such a scheme does exist, what ownership
information to keep. Like which cluster the disk
belongs to. If it belongs to a particular cluster, is
it owned explicitly by a single node of the cluster,
or by all the nodes of the cluster.... etc, etc.
3. If such a scheme exists, will all the other
operating systems that have access to the disk will be
able to interpret and handle that properly.


Just dumping my brain. Probably this may be a no-issue
at all. Hope so.

Thanks,


--- David Brower <david.brower@oracle.com> wrote:
> Many systems will discover all visible LUNs on the
> SAN and make them visible as raw devices.  If it's
> Windows,
> it'll try to mount all the ones that look like file
> systems;
> on UNIX, mounting is limited by fstab, but not
> creation of
> /dev disk partitions.
> 
> To keep nodes from picking up disks they aren't
> supposed
> to see (or mount), you can do things like program
> the domains
> of the SAN or the disks (eg: brocade switch), or
> rely on
> higher level software to negotiate between nodes
> (eg: MSCS).
> 
> Discovery often involves probe operations, which can
> be very
> time consuming on a SAN; some systems cache things
> they saw
> last time in an attempt to reduce boot time, but
> this gets
> complicated when storage is altered in their SAN
> visibility.
> 
> -dB
> 
> Rob Latham wrote:
> > 
> > On Fri, Oct 05, 2001 at 10:34:49AM -0700,
> Ramachandra Pai wrote:
> > 
> > > In a cluster with storage disks on SAN, what is
> the
> > > mechanism to identify which disks belong to
> which
> > > cluster?  NOTE: there can be many many nodes on
> the
> > > SAN, all of which may not be clustered with each
> > > other.
> > 
> > i may be missing something, but isn't that called
> an "fstab" ?
> > 
> > ==rob
> > 
> > --
> > [ Rob Latham <rlatham@plogic.com>        
> Developer, Admin, Alchemist ]
> > [ Paralogic Inc. - www.plogic.com                 
>                    ]
> > [                                                 
>                    ]
> > [ EAE8 DE90 85BB 526F 3181                   1FCF
> 51C4 B6CB 08CC 0897 ]
> > 
> > Linux-cluster: generic cluster infrastructure for
> Linux
> > Archive:      
> http://mail.nl.linux.org/linux-cluster/
> 
> Linux-cluster: generic cluster infrastructure for
> Linux
> Archive:      
http://mail.nl.linux.org/linux-cluster/


=====
Ram Pai  
IBM Corporation,  
Linux Technology Center,
linuxram@yahoo.com or pair@us.ibm.com

EVMS Development - http://www.sf.net/projects/evms

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Linux-cluster: generic cluster infrastructure for Linux
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