NAME
st_san_safe — determines whether access to stape device special files without the no-rewind-on-close option are allowed
VALUES
Allowed values
0 (off)
any positive integer (on)
Recommended values
0 (off)
or
1 (on)
DESCRIPTION
This tunable notifies the stape driver whether it should allow access to device
special files without the no-rewind-on-close option.
With this tunable
on,
the stape driver will fail any open on a stape device special file without
the no-rewind-on-close option (i.e.,
/dev/rmt/1m
or
/dev/rmt/1mb)
with a status of
EINVAL.
The
st_san_safe
tunable allows the safe sharing of tape devices in SAN tape backup solution
configurations.
The disabling of device special files without no-rewind-on-close in a
SAN tape backup solution configuration prevents the accidental sending
of a rewind command on close from HP-UX systems via standard tape
commands like
mt(1)
which would corrupt a backup in process.
Who Is Expected to Change This Tunable?
Anyone.
Restrictions on Changing
Changes to this tunable take effect immediately.
When Should the Tunable Be Turned On?
This tunable should be turned
on
if the system is going to be used in a SAN tape backup solution configuration.
What Are the Side Effects of Turning the Tunable On?
The stape driver will fail any open to a stape device special file
that does not have the no-rewind-on-close option with a status of
EINVAL.
This behavior prevents the usage of any stape device special file without the
no-rewind-on-close option.
When Should the Tunable Be Turned Off?
If the system is
not
part of a SAN tape backup solution configuration or the system utilizes
frecover(1M), this tunable should be turned
off.
frecover(1M)
will not function unless it has access to device special files without
the no-rewind-on-close option.
What Are the Side Effects of Turning the Tunable Off?
A rewind may be issued from this system accidentally on close possibly
corrupting a backup being issued from another system on the SAN.
What Other Tunables Should Be Changed at the Same Time?
None.
WARNINGS
All HP-UX kernel tunable parameters are release specific.
This parameter may be removed or have its meaning changed in
future releases of HP-UX.
Installation of optional kernel software, from HP or other vendors,
may cause changes to tunable parameter values. After installation,
some tunable parameters may no longer be at the default or
recommended values. For information about the effects of
installation on tunable values, consult the documentation
for the kernel software being installed.
For information about optional kernel software that was
factory installed on your system, see
HP-UX Release Notes
at
http://docs.hp.com.
AUTHOR
st_san_safe
was developed by Hewlett-Packard.
