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On 14 April 2010 23:06, Peter Noerr <[log in to unmask]> wrote:
> Leaving aside the point (for the moment) of *what* is reported; it is clear that Source uptime/reliability must be measured from an outside point (or points). However the Zeerex information is returned by the Source itself in response to a request.

Not (necessarily) so.  From the earliest days of the ZeeRex work it
was envisaged that databases of ZeeRex records would exist, describing
services other than themselves.  See
        http://explain.z3950.org/overview/index.html#4
for some background, and
        http://irspy.indexdata.com/doc.html?module=ZOOM/IRSpy/WebService.pod
for an example.



> Thus there must be some mechanism for a Source to obtain this information from the outside "measurement point(s)" so it can pass it to the querying system. Isn't it then easier for the querying system to just ask that measurement point for details of a number of Sources and make a decision on that basis?
>
> What I'm really questioning is whether a zeerex response from a Source is the right place for this information - whatever it is.
>
> In one very real sense it is the right place, because then each Source can decide for itself if it wants to obtain and make available this information. But then each Source has to set up some external measuring point to get the information, and the method of getting it back, and storing it. Not difficult, but another thing to set up, maintain and manage.
>
> To make this easier it might be interesting to consider a "query mirror" server, which the Source could send a query message to, and which would bounce the message back to the Source. The dumber it is the better, so the Source can handle its own authentication and API/protocol/language issues with the mirror needing to know nothing about them. And a dumb query mirror could be easily deployed at many locations to handle traffic for many Sources. Possibly as a SRU server add-on? (The old psychiatrists joke "You're fine, how am I?" comes to mind.)
>
> Peter
>
>
>> -----Original Message-----
>> From: SRU (Search and Retrieve Via URL) Implementors
>> [mailto:[log in to unmask]] On Behalf Of Edward C. Zimmermann
>> Sent: Wednesday, April 14, 2010 6:46 AM
>> To: [log in to unmask]
>> Subject: Re: Add "reliability" index to CQL's "zeerex" context set
>>
>> That's the point of "global" service monitoring...
>>
>> Running search to ones own targets in ones own networks does not need
>> it.. but
>> also it a club house.. ZeeRex/Explain is about going beyond the private
>> club.
>>
>> On Wed, 14 Apr 2010 09:01:15 -0400, Ross Singer wrote
>> > On Wed, Apr 14, 2010 at 6:51 AM, Mike Taylor <[log in to unmask]>
>> wrote:
>> > > Peter, we didn't envisage this as something that servers self-
>> report,
>> > > but as something measured from the outside.  To a client, it's
>> > > irrelevant whether a server is running off a UPS, for example: all
>> we
>> > > care about is whether we can contact and search in and retrieve
>> from
>> > > the server.
>> >
>> > On the flip-side, though, if something's wrong between you and that
>> > particular service (let's say a DNS server in your network goes
>> > haywire and intermittently forgets certain domains, or something),
>> > this service's reliability is tarnished through no fault of its own.
>> > Or, let's say, for example, your ISP has decided that service X
>> > hasn't paid enough of a toll to get priority to its customers...
>> >
>> > -Ross.
>>
>>
>> --
>>
>> Edward C. Zimmermann, NONMONOTONIC LAB
>> Basis Systeme netzwerk, Munich Ges. des buergerl. Rechts
>> http://www.nonmonotonic.net
>> Umsatz-St-ID: DE130492967
>