Pageable and Nonpageable Memory

Before you can detach a board, the operating system must vacate the memory on that board. Vacating a board means flushing its pageable memory to swap space and copying its nonpageable (that is, kernel and OBP memory) to another memory board. To relocate nonpageable memory, the operating environment on a domain must be temporarily suspended, or quiesced. The length of the suspension depends on the domain I/O configuration and the running workloads. Detaching a board with nonpageable memory is the only time when the operating environment is suspended; therefore, you should know where nonpageable memory resides, so you can avoid significantly impacting the operation of the domain. When permanent memory is on the board, the operating environment must find other memory to receive the copy.

You can use the dr(1M) command drshow(1M) to determine whether the memory on a board is pageable or nonpageable:

% dr
dr> drshow board_number mem

Similarly, you can determine whether the memory on a board is pageable by looking at the DR Memory Configuration window, which is available when you perform a detach operation within Hostview. The DR Memory Configuration window is described in the Sun Enterprise 10000 DR Configuration Guide in the Solaris 8, Update 6, Sun Hardware Answerbook Collection.