st_ats_enabled(5) OBSOLETED st_ats_enabled(5)NAMEst_ats_enabled - determine whether to reserve a tape device on open
(OBSOLETED)
VALUES
Default
Allowed values
or
Recommended values
DESCRIPTION
Note: this tunable is obsoleted and has been renamed to beginning with
release HP-UX 11i v3.
This tunable notifies the stape or estape driver whether it needs to
reserve a tape device on open and subsequently release it on close.
When this tunable is on the stape or estape driver will attempt to
reserve any tape device on open. The driver has a few tape devices
flagged as suitable devices for this functionality including DLT 8000,
DLT 7000, STK 9840, HP Ultrium, and others. DDS drives are not flagged
for this functionality.
The tunable allows the safe sharing of tape devices in multinode con‐
figurations like MC/ServiceGuard's Advanced Tape Sharing. The auto‐
matic reserve and release protects the tape device from being accessed
from multiple nodes which would corrupt a backup. If the reserve por‐
tion of the stape or estape driver's open routine fails, a status of is
returned.
Who Is Expected to Change This Tunable?
Anyone.
Restrictions on Changing
Changes to this tunable take effect immediately and are used during the
next open or close.
When Should the Tunable Be Turned On?
This tunable should be turned on if the system will be used in an
MC/ServiceGuard Advanced Tape Sharing configuration or the user wants
the stape or estape driver to use automatic reserve or release on open
and close for multinode manageability.
What Are the Side Effects of Turning the Tunable On?
A reserve is sent to the tape device by the stape or estape driver on
open and a release is sent on close. No other initiator or HBA will be
able to access the tape device while it is opened on another initiator
or HBA.
When Should the Tunable Be Turned Off?
This tunable should be turned off for any SAN tape sharing solution
configuration other than ATS. Most multinode backup applications (for
example, Omniback) manage device reservation themselves and any inter‐
ference by the stape or estape driver may produce problems. This tun‐
able should also be turned off for any multiplatform SAN configuration
to keep tape access across platforms more uniform.
What Are the Side Effects of Turning the Tunable Off?
Unauthorized access from another initiator might interfere with any
current tape operation.
What Other Tunables Should Be Changed at the Same Time?
None.
WARNINGS
All HP-UX kernel tunable parameters are release specific. This parame‐
ter 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 val‐
ues. For information about the effects of installation on tunable val‐
ues, consult the documentation for the kernel software being installed.
For information about optional kernel software that was factory
installed on your system, see at
AUTHOR
was developed by HP.
SEE ALSOst_ats_enable(5), scsi_tape(7), scsimgr_estape(7).
Tunable Kernel Parameters st_ats_enabled(5)