Memory; Pageable And Nonpageable Memory - Sun Microsystems Sun Enterprise 10000 Dynamic Reconfiguration User Manual

A board that hosts non-vital system resources can be detached whether or not there
are alternate paths to the resources. All of the devices on the board must be closed
before the board can be detached; all of its file systems must be unmounted; and, its
swap partitions must be deleted. You may have to kill processes that have open files
or devices, or place a hard lock on the file systems (using lockfs(1M)) before you
unmount the boards.
All I/O device drivers involved with I/O devices on the board(s) must support the
DDI_DETACH option in the detach entry-point of the driver. This option releases all
system resources associated with that device or adapter.

Memory

If you use memory interleaving between system boards, those system boards cannot
be detached because DR does not yet support interboard interleaving. By default,
hpost(1M) does not set up boards with interleaved memory. Look for the following
line in the hpost(1M) file .postrc (see postrc(4)):
mem_board_interleave_ok
If mem_board_interleave_ok is present, you may not be able to detach a board
that uses memory interleaving.
Note – If you use the ndd(1m) command to set the configuration parameters for
network drivers, the parameters may not persist after a DR Detach or DR Attach
operation. Use the /etc/system file or the driver.conf file for a specific driver
to set the parameters permanently.

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.
Chapter 5