Wednesday, 28 November 2012

Lesson-4 Object Data Manager (ODM)

What is ODM ?
  • ODM – Object Data Manager  is the database for storing system information.
  • Physical and logical devices  information are stored and  maintained as objects in ODM.
  • It is in binary format hence can't view or edit.
  • Whenever we add, delete and configure the devices in OS, the entries will be added in ODM
System Data Managed by  ODM

1) Device Configuration information (Predefined and Customized Devices )
2) Software Vital Product Data (SVPD)
3) System Resource Controller
4) TCP/IP configuration information
5) SMIT menus and commands
6) NIM  information
7) Error Log and dump information.


Data Not Managed by ODM

            The Filesystem information, User/Security information and  Queues & its devices are not manged by ODM.

How ODM is compared with Rational Database?

            ODM  is more or less similar  to  Relational Database.
1. Object Class is equivalent  to the database file.
2. Objects are  equivalent are to the row of the database.
3. Object descriptors are equivalent to the column of the database
                   OC   --  datafiles
                     O   --  records
                    OD  --  fields 

Where the ODMDIR environment variable declared?
            ODMDIR environment variable is declared  in /etc/environment. The default ODMDIR variable is /etc/objrepos. 

Types of ODM Components & Commands associated with them
            ODM have 3 components, they are Object Classes, Objects and Descriptors

 Object Classes: (odmcreate, odmdrop)
            The ODM contains many database files.  Each file is called  Object Class.
            Commands Used
            #odmcreate desc_file.cre  (Create ODM class file)
            #odmdrop -o desc_file.cre (Delete entire ODM class)

Objects:  (odmadd,odmdelete,odmget,odmchange)
            Each  object class contains of  objects. Each object is one record in an object class

            Commands Used
            #odmget -q name=hdisk0  CuDv
                        The above command is used to display the object  hdisk0 in the CuDV
          #odmdelete –o CuDv –q name=hdisk0
                        The above command is used to delete the specified object hdisk0 in ODMe
Descriptors: (odmshow)
            It describes layout of the object. They determine the name and datatype of the fields that are part of the object classes.

            #odmshow  object_class_name
            #odmshow PdDv
            #odmshow CuDv

Device Configuration Summary

What are Device Database aka Object Class files?
            There are 2 important  device database or Object class files are there in ODM, they are Predefined device and Customized  device
  1. Predefined device information describes all supported devices.  (PdDv,PdAt,PdCn). If  the device to be configured, it must be the part of  PdDv class, it is not possible to configure a device without defined in the corresponding Pd classes.
  1. Customized device information describes all  the devices that are attached to the system. (CuDv, CuAt, CuDep, CuDvDr, CuVPD, Config_Rules). If the device is in defined state, it should have entry in CuDv.

What are the states of  devices in the  ODM?

            There are 2 important states of devices in the ODM, they are  Defined and Available

    Defined State  (device status will be 0 )
  •  If a device is in the defined state there is an entry in ODM class CuDv.
  • A device can be either defined by cfgmgr or mkdev command . Both methods use “define method” (cfgmgr) to generate instance in the class CuDv. 
  •  Suppose that installed device is removed from server or hdd has failed. This case that device is moved to defined state. i.e. that device configuration is available in server but currently device is not accessible.
    Available State (device status will be 1)
  •  When the device is in available, the device driver has been loaded and special device file is configured under  /dev  directory and the device is ready for accessible. 
  •   The "configure method" is used to load the device driver and add an entry in the /dev directory
 In addition to the above the following state also availble                     


    The device is supported device but not configured. Devices reside in the Predefined Database  not customized database.

        The difference between Defined and Available state is that no device driver loaded into the kernel.

What are the commands used to get device informations?
  • lsdev command  to get information about PdDv and CuDv. 
  • lsattr command  to get information about PdAt and CuAt.  

 SWVPD (Software Vital Product Data)

  • VPD is the Vital Product data which is the subset of ODM. 
  • Using  lscfg  can find the VPD data of the hardware devices.
   The following are objects of VPD
1)      LPP  (Contains information about the product)
2)      Inventory ( contains files associated with s/w product)
3)      Product ( information of the prdt)
4)      History (Historical info about software)

Object Class Repositories
     There are 3 repositories, in which ODM  data are stored.

i) /etc/objrepos
  • This is the main repository file. Data that is specified to the system is stored. 
  • /(root) part of the s/w contains the part of the product that cannot be shared through networks. 
  • Customized Devices object classess (CuDv,CuAt)
ii) /usr/lib/objrepos
  • Predefined device object classess  (PdDv.PdAt) 
  • Platform specific data that can be shared across the network.
  • SMIT menu objectclasses and /usr part of the SWVPD. 
  • The four object classes used by SWVPD for the /usr part of installable s/w prdt sofw installed in /usr part can be  shared among the h/w arch
iii) /usr/share/lib/objrepos
  • /usr/share part of the SWVPD (history, inventory,lpp,product). 
  • Platform independent data can be shared across the systems.


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