Special Handling For Tape Devices - Sun Microsystems Sun Enterprise 10000 Dynamic Reconfiguration User Manual

To enable device suspension for the soc and pln drivers, you must edit the /etc/
system file so that the pln_enable_detach_suspend and
soc_enable_detach_suspend variables are set to 1, as in the following example:
set pln:pln_enable_detach_suspend=1
set soc:soc_enable_detach_suspend=1
The operating environment refuses a quiesce request if a suspend-unsafe device is
open. If you can manually suspend the device, you can force the operating
environment to quiesce. To manually suspend the device, you may have to close the
device by killing the processes that have it open, ask users not to use the device, or
disconnect the cables. For example, if a device that allows asynchronous unsolicited
input is open, you can disconnect its cables prior to quiescing the operating
environment, preventing traffic from arriving at the device and the device from
accessing the domain centerplane. You can reconnect the cables after the operating
environment resumes. If you cannot make a device suspend its access to the domain
centerplane, you should not force the operating environment to quiesce. Doing so
could cause a domain to crash or hang. Instead, postpone the DR operation until the
suspend-unsafe device is no longer open.
Caution – If you attempt a forced quiesce operation while activity is occurring on a
suspend-unsafe device, the domain may hang. However, if the domain hangs, it will
not affect other domains that are running on the Sun Enterprise 10000 system.

Special Handling for Tape Devices

For the Solaris 8 operating environment, tape devices that are natively supported by
Sun Microsystems™ are suspend-safe and detach-safe (see st(7D) for a list of
natively-supported drives). If a system board that you are detaching contains a
natively-supported tape device, you can safely detach the board without suspending
the device. If you want to use a tape device that is not natively supported by Sun
Microsystems, you can use it, but you should make it detach-safe. To ensure correct
input/output and DR operations, you need to make a suitable entry in /kernel/
drv/st.conf with the ST_UNLOADABLE (0x0400) flag set in the entry (see st(7D)
for more information). After you update st.conf, you must reboot the domain to
process the new entry.
Chapter 13