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5819 want dumpadm(1m) option to print estimated dump size
   1 DUMPADM(1M)                  Maintenance Commands                  DUMPADM(1M)
   2 
   3 
   4 
   5 NAME
   6        dumpadm - configure operating system crash dump
   7 
   8 SYNOPSIS
   9        /usr/sbin/dumpadm [-nuy] [-c content-type] [-d dump-device]
  10             [-m mink | minm | min%] [-s savecore-dir]
  11             [-r root-dir] [-z on | off]
  12 
  13 
  14 DESCRIPTION
  15        The dumpadm program is an administrative command that manages the
  16        configuration of the operating system crash dump facility. A crash dump
  17        is a disk copy of the physical memory of the computer at the time of a
  18        fatal system error. When a fatal operating system error occurs, a
  19        message describing the error is printed to the console. The operating
  20        system then generates a crash dump by writing the contents of physical
  21        memory to a predetermined dump device, which is typically a local disk
  22        partition. The dump device can be configured by way of dumpadm. Once
  23        the crash dump has been written to the dump device, the system will
  24        reboot.
  25 
  26 
  27        Fatal operating system errors can be caused by bugs in the operating
  28        system, its associated device drivers and loadable modules, or by
  29        faulty hardware.  Whatever the cause, the crash dump itself provides


 117 
 118 
 119            swap
 120                If the special token swap is specified as the dump device,
 121                dumpadm examines the  active swap entries and selects the most
 122                appropriate entry to configure as the dump device. See
 123                swap(1M). Refer to the NOTES below for details of the algorithm
 124                used to select an appropriate swap entry.  When the system is
 125                first installed with a UFS root file system, dumpadm uses the
 126                value for swap to determine the initial dump device setting. A
 127                given ZFS volume cannot be configured for both the swap area
 128                and the dump device.
 129 
 130 
 131            none
 132                If the special token none is specified, the active dump device
 133                is removed and crash dumps are disabled.
 134 
 135 
 136 




 137        -m mink | minm | min%
 138            Create a minfree file in the current savecore directory indicating
 139            that savecore should maintain at least the specified amount of free
 140            space in the file system where the savecore directory is located.
 141            The min argument can be one of the following:
 142 
 143            k
 144                A positive integer suffixed with the unit k specifying
 145                kilobytes.
 146 
 147 
 148            m
 149                A positive integer suffixed with the unit m specifying
 150                megabytes.
 151 
 152 
 153            %
 154                A % symbol, indicating that the minfree value should be
 155                computed as the specified percentage of the total current size
 156                of the file system containing the savecore directory.


 310    Minimum Free Space
 311        If the dumpadm -m option is used to create a minfree file based on a
 312        percentage of the total size of the file system containing the savecore
 313        directory, this value is not automatically recomputed if the file
 314        system subsequently changes size.  In this case, the administrator must
 315        re-execute dumpadm -m to recompute the minfree value. If no such file
 316        exists in the savecore directory, savecore will default to a free space
 317        threshold of one megabyte. If no free space threshold is desired, a
 318        minfree file containing size 0 can be created.
 319 
 320    Security Issues
 321        If, upon reboot, the specified savecore directory is not present, it
 322        will be created prior to the execution of savecore with permissions
 323        0700 (read, write, execute by owner only) and owner root. It is
 324        recommended that alternate savecore directories also be created with
 325        similar permissions, as the operating system crash dump files
 326        themselves may contain secure information.
 327 
 328 
 329 
 330                                February 15, 2013                   DUMPADM(1M)
   1 DUMPADM(1M)                  Maintenance Commands                  DUMPADM(1M)
   2 
   3 
   4 
   5 NAME
   6        dumpadm - configure operating system crash dump
   7 
   8 SYNOPSIS
   9        /usr/sbin/dumpadm [-enuy] [-c content-type] [-d dump-device]
  10             [-m mink | minm | min%] [-s savecore-dir]
  11             [-r root-dir] [-z on | off]
  12 
  13 
  14 DESCRIPTION
  15        The dumpadm program is an administrative command that manages the
  16        configuration of the operating system crash dump facility. A crash dump
  17        is a disk copy of the physical memory of the computer at the time of a
  18        fatal system error. When a fatal operating system error occurs, a
  19        message describing the error is printed to the console. The operating
  20        system then generates a crash dump by writing the contents of physical
  21        memory to a predetermined dump device, which is typically a local disk
  22        partition. The dump device can be configured by way of dumpadm. Once
  23        the crash dump has been written to the dump device, the system will
  24        reboot.
  25 
  26 
  27        Fatal operating system errors can be caused by bugs in the operating
  28        system, its associated device drivers and loadable modules, or by
  29        faulty hardware.  Whatever the cause, the crash dump itself provides


 117 
 118 
 119            swap
 120                If the special token swap is specified as the dump device,
 121                dumpadm examines the  active swap entries and selects the most
 122                appropriate entry to configure as the dump device. See
 123                swap(1M). Refer to the NOTES below for details of the algorithm
 124                used to select an appropriate swap entry.  When the system is
 125                first installed with a UFS root file system, dumpadm uses the
 126                value for swap to determine the initial dump device setting. A
 127                given ZFS volume cannot be configured for both the swap area
 128                and the dump device.
 129 
 130 
 131            none
 132                If the special token none is specified, the active dump device
 133                is removed and crash dumps are disabled.
 134 
 135 
 136 
 137        -e
 138            Estimates the size of the dump for the current running system.
 139 
 140 
 141        -m mink | minm | min%
 142            Create a minfree file in the current savecore directory indicating
 143            that savecore should maintain at least the specified amount of free
 144            space in the file system where the savecore directory is located.
 145            The min argument can be one of the following:
 146 
 147            k
 148                A positive integer suffixed with the unit k specifying
 149                kilobytes.
 150 
 151 
 152            m
 153                A positive integer suffixed with the unit m specifying
 154                megabytes.
 155 
 156 
 157            %
 158                A % symbol, indicating that the minfree value should be
 159                computed as the specified percentage of the total current size
 160                of the file system containing the savecore directory.


 314    Minimum Free Space
 315        If the dumpadm -m option is used to create a minfree file based on a
 316        percentage of the total size of the file system containing the savecore
 317        directory, this value is not automatically recomputed if the file
 318        system subsequently changes size.  In this case, the administrator must
 319        re-execute dumpadm -m to recompute the minfree value. If no such file
 320        exists in the savecore directory, savecore will default to a free space
 321        threshold of one megabyte. If no free space threshold is desired, a
 322        minfree file containing size 0 can be created.
 323 
 324    Security Issues
 325        If, upon reboot, the specified savecore directory is not present, it
 326        will be created prior to the execution of savecore with permissions
 327        0700 (read, write, execute by owner only) and owner root. It is
 328        recommended that alternate savecore directories also be created with
 329        similar permissions, as the operating system crash dump files
 330        themselves may contain secure information.
 331 
 332 
 333 
 334                                  April 9, 2015                     DUMPADM(1M)