Distinction between WBEM Server and CIMOM Server

[Anukalp Desai]

I was reading SMI S standard as well as information available on web about SMI S and came across WBEM Server and
CIMOM Server on wikipedia, IBM website and am not able to understand the distinction.

I thought that a WBEM Client would directly communicate with the Provider?

Wikipedia says that WBEM Server is the one which maintains the object oriented Model of the actual physical storage
device and client performs operations on the model which are then propagated to the actual physical storage device
by the Providers.

1. Are WBEM Server and CIM Object Manager Server one and the same and are they required to be installed separately
    with the Providers?

2. CIM Object Manager Server also maintains a repository/database, does this repository/database the object oriented
    model of WBEM Server that wikipedia is talking about.

wikipedia link
http://en.wikipedia.org/wiki/Web-Based_Enterprise_Management

[Peter Lamanna]

Hi Anukalp,

In response to your questions below.

1.  Yes, the CIMOM and WBEM Server are one and the same.  The provider is a separate component.  The WBEM Server loads the provider and serves as it host.  The provider therefore does not run outside of the WBEM Server process except in the case of remote execution.

2. Yes, the CIM Repository is where the CIM classes are stored.  When a MOF is compiled and loaded the constructs contained within the file are stored in the repository.

The WBEM Client communicates with the WBEM Server using one the WBEM protocols.  The server routes client requests to the appropriate provider based on the referenced resource.  The role of the provider is to fulfill the request against the targeted managed resource e.g. storage device.

Please let me know if you have any further questions.

Peter

Sent from my iPhone

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[Anukalp Desai]

Hi Peter,

Thank you for your reply.

Please also let me know whether the WBEM server maintains the object model of the managed resource in its memory and what ever operations
are requested by the client are performed on this object model, further the provider is the one which would populate the object model
with current state of the managed resource as well as make sure that the state of the object model of the managed resource is in the same state
as the managed resource?

Does the WBEM Server host multiple providers? If yes then are there different providers for each profile or how many providers could
be hosted by the WBEM Server?

Thanks again for your help!

[Paul Robert Marino]

That depends more on the provider than the WBEM server some providers
dont play nice with others however in theory you can have as many as
the WBEM server can handle. Each WBEM server may have different
limitations but most can handle more than would be practical on a
single WBEM server instance.

>
> Thanks again for your help!
>

[Jim Davis]

From a client perspective you should think of this as a SMI Agent and ignore the details of providers, etc. A client communicates with a SMI Agent (the combination of the WBEM Server and providers) to manage/monitor storage devices. For SMI, the protocol is CIM-XML (and optionally WS-Management). 

To answer your questions

(1) the term Provider is misused by many…. A provider is simply component that sits between the WBEM Server and a managed element - it will handle requests from the server. In many implementations each CIM Class will have a provider, so there may be hundreds or thousands of providers that are managed by a single WBEM Server.  

(2) The object model resource in its memory - this is an implementation detail, it could be in memory, cached, etc. - it is irrelevant to the client and providers how this is managed by the WBEM Server.

 

Jim Davis
CTO
910-528-5511