st_san_safe(5)                                               st_san_safe(5)
                          Tunable Kernel Parameters



 NAME    [Toc]    [Back]
      st_san_safe - determines whether access to stape device special files
      without the no-rewind-on-close option are allowed

 VALUES    [Toc]    [Back]
    Failsafe
      0 (off)

    Default    [Toc]    [Back]
      1 (on)

    Allowed values    [Toc]    [Back]
      0 (off)
      any positive integer (on)

    Recommended values    [Toc]    [Back]
      0 (off) or 1 (on)

 DESCRIPTION    [Toc]    [Back]
      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    [Toc]    [Back]
      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



 Hewlett-Packard Company            - 1 -      HP-UX 11i Version 2: Sep 2004






 st_san_safe(5)                                               st_san_safe(5)
                          Tunable Kernel Parameters



      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    [Toc]    [Back]
      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    [Toc]    [Back]
      st_san_safe was developed by Hewlett-Packard.

 SEE ALSO    [Toc]    [Back]
      scsi_tape(7).


 Hewlett-Packard Company            - 2 -      HP-UX 11i Version 2: Sep 2004