norewind_close_disabled.5 (2010 09)

n
norewind_close_disabled(5) norewind_close_disabled(5)
(Tunable Kernel Parameters)
NAME
norewind_close_disabled - determine whether access to tape device special files without the no-rewind-
on-close option is allowed
VALUES
Default
0 (off)
Allowed values
0 (off)
1 (on)
DESCRIPTION
Note: this tunable was named
st_san_safe in releases prior to HP-UX 11i v3.
This tunable notifies the tape driver whether it should allow access to device special files without the no-
rewind-on-close option. When this tunable is on, the tape driver will fail any open on a tape device spe-
cial file that does not have the no-rewind-on-close option (that is,
/dev/rmt/1m or /dev/rmt/1mb)
with a status of [EINVAL].
The
norewind_close_disabled
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, 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 tape driver will fail any open to a tape 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 tape device special file without
the no-rewind-on-close option.
When Should the Tunable Be Turned Off?
This tunable should be turned off if the system is not part of a SAN tape backup solution configuration or
the system utilizes
frecover. frecover 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 accidentally from this system 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.
EXAMPLES
Query the current value of the tunable:
scsimgr get_attr -d estape
Set the value of the tunable to 1:
scsimgr set_attr -d estape -a norewind_close_disabled=1
To save the value of the tunable across reboots:
scsimgr save_attr -d estape -a norewind_close_disabled=1
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1