VMware Training

Jay Ashworth jra at baylink.com
Thu Feb 20 18:16:23 UTC 2014


----- Original Message -----
> From: "Eugeniu Patrascu" <eugen at imacandi.net>

> On Wed, Feb 19, 2014 at 10:06 PM, Jay Ashworth <jra at baylink.com>
> wrote:
> 
> > ----- Original Message -----
> > My understanding of "cluster-aware filesystem" was "can be mounted at the
> > physical block level by multiple operating system instances with complete
> > safety". That seems to conflict with what you suggest, Eugeniu; am I
> > missing something (as I often do)?
> 
> What you are saying is true and from VMware's point of view, an ISCSI
> volume is a physical disk.
> And you can mount the same ISCSI disk on many VMware hosts. Just write
> into different directories on the disk.
> 
> Am I missing something in your question ?

I guess.  You and Jimmy seem to be asserting that, in fact, you *cannot* 
mount a given physical volume, with a clustering FS in its partition, 
onto multiple running OS images at the same time... at which point, why 
bother using a clustering FS?

The point of clustering FSs (like Gluster, say), as I understood it,
was that they could be mounted by multiple machines simultaneously: that
there was no presumed state between the physical blocks and the FS driver
inside each OS, which would cause things to Fail Spectacularly if more
than one machine was simultaneously using them in realtime.

You and Jimmy seem to be suggesting that multiple OSs need to be semaphored.

One of three understandings here is wrong.  :-)

Cheers,
-- jra
-- 
Jay R. Ashworth                  Baylink                       jra at baylink.com
Designer                     The Things I Think                       RFC 2100
Ashworth & Associates       http://www.bcp38.info          2000 Land Rover DII
St Petersburg FL USA      BCP38: Ask For It By Name!           +1 727 647 1274



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