diskpatch(1M)                                                    diskpatch(1M)



NAME
     diskpatch - prevent stiction problems with some disk drives

SYNOPSIS
     diskpatch [-v] [-H halt [-S delay] [-F]] [-W]

DESCRIPTION
     diskpatch is normally run from cron(1M) twice a week and whenever the
     system is shutdown.  It uses the hardware inventory mechanism to find all
     the disk drives on the system attached to the supported SCSI controllers,
     (excluding the jag(7M) controller) and determines the type of disk drive
     by sending the SCSI inquiry command, using the ds(7M) driver.

     If the drive is found to be one of the susceptible drives, a special
     command is issued to the drive that causes it to spin down (stop) for a
     brief period, and then start again.  This sequence prevents the stiction
     from occurring, in most cases (stiction means that the magnetic heads
     have become stuck to the surface of the drive media, usually preventing
     the drive from starting and preventing the drive from being used).

     The options are:

     -v        Verbose mode.  The inquiry info for each disk drive found is
               printed.

     -H halt   Send a vendor specific command to the affected disk drives that
               will usually prevent stiction from occurring.  halt is the
               interval in seconds the drive will remain halted; the interval
               should be 30 seconds.  Normally this command is ignored by the
               disk drive if it has been running less than 48 hours since last
               turned off or the command was last issued.

     -F        Forces the cleaning action specified by -H regardless of time
               since last issued or hours powered on.

     -S delay  Specify the delay in seconds between sets of drives, to avoid
               overloading the drive's power supply.  An attempt is made to
               overlap drives to reduce the overall runtime.

     -W        Warns if the firmware isn't new enough to support this command,
               and the disk appears to be one of the susceptible disk drives.

NOTE
     This command must be run as the superuser.

SEE ALSO
     cron(1M), ds(7M).








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