Hi Florian,

On Tue, Jun 14, 2011 at 02:03:19PM +0200, Florian Haas wrote:
> On 2011-06-14 13:08, Dejan Muhamedagic wrote:
> > Hi Alan,
> > 
> > On Mon, Jun 13, 2011 at 10:32:02AM -0600, Alan Robertson wrote:
> >> On 06/13/2011 04:12 AM, Simon Talbot wrote:
> >>> A couple of observations (I am sure there are more) on the uniqueness 
> >>> flag for OCF script parameters:
> >>>
> >>> Would it be wise for the for the index parameter of the SFEX ocf script 
> >>> to have its unique flag set to 1 so that the crm tool (and others) would 
> >>> warn if one inadvertantly tried to create two SFEX resource primitives 
> >>> with the same index?
> >>>
> >>> Also, an example of the opposite, the Stonith/IPMI script, has parameters 
> >>> such as interface, username and password with their unique flags set to 
> >>> 1, causing erroneous warnings if you use the same interface, username or 
> >>> password for multiple IPMI stonith primitives, which of course if often 
> >>> the case in large clusters?
> >>>
> >>
> >> When we designed it, we intended that Unique applies to the complete set 
> >> of parameters - not to individual parameters.  It's like a multi-part 
> >> unique key.  It takes all 3 to create a unique instance (for the example 
> >> you gave).
> > 
> > That makes sense. 
> 
> Does it really? Then what would be the point of having some params that
> are unique, and some that are not? Or would the tuple of _all_
> parameters marked as unique be considered unique?

Consider the example above for sfex. It has a device and index
which together determine which part of the disk the RA should
use. Only the device:index tuple must be unique.  Currently,
neither device nor index is a unique parameter (in the
meta-data). Otherwise we'd have false positives for the
following configuration:

disk1:1
disk1:2
disk2:1
disk2:2

Now, stuff such as configfile and pidfile obviously both must be
unique independently of each other. There are probably other
examples of both kinds.

Cheers,

Dejan



> Florian
> 



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