Oracle asm disk string profile string vs param string
asm_diskstring can be set in the ASM parameterfile and in the GPnP profile as well. Grid Infrastructure needs to know where to search for ASM disks before starting ASM and reading the ASM parameterfile, the GPnP profile makes that possible.

dsget

dsget
        Retrieves the discovery diskstring value that is
        used by the Oracle ASM Instance and its clients

Synopsis
        dsget [ --normal | --profile [ -f ] | --parameter ]

Description
        The options for the dsget command are described below.

        --normal        - Retrieves the discovery string from the Grid Plug
                          and Play (GPnP) profile and the one that is set in
                          the Oracle ASM instance. It returns one row each for
                          the profile and parameter setting. This is the
                          default setting.

        --parameter     - Retrieves the ASM_DISKSTRING parameter setting of
                          the Oracle ASM instance.

        --profile       - Retrieves the discovery string from the GPnP
                          profile.

        -f              - If -f is specified, retrieves the discovery string
                          from the local GPnP profile.  This parameter
                          can only be specified if --profile is specified.

Examples
        The following example uses dsget to retrieve the current discovery
        diskstring value from the GPnP profile and the ASM_DISKSTRING parameter.

        ASMCMD [+] &gt; dsget
        profile: /devices/disk*
        parameter: /devices/disk*