FSSCONFIG(8)            NetBSD System Manager's Manual            FSSCONFIG(8)

     fssconfig -- configure file system snapshot devices

     fssconfig [-cxv] device path backup [cluster [size]]
     fssconfig -u [-v] device
     fssconfig -l [-v] [device]

     The fssconfig command configures file system snapshot pseudo disk
     devices.  It will associate the file system snapshot disk device with a
     snapshot of path allowing the latter to be accessed as though it were a

     If backup resides on the snapshotted file system a persistent snapshot
     will be created.  This snapshot is active until backup is unlinked.  This
     snapshot mode is only supported for ffs files systems.

     Otherwise data written through the path will be saved in backup.  If
     backup is a regular file, it will be created with length size.  Default
     size is the size of path.  Data is saved to backup in units of cluster

     Options indicate an action to be performed:

     -c   Configures the device.  If successful, references to device will
          access the contents of path at the time the snapshot was taken.  If
          backup is a directory, a temporary file will be created in this
          directory.  This file will be unlinked on exit.

     -l   List the snapshot devices and indicate which ones are in use.  If a
          specific device is given, then only that will be described.

     -u   Unconfigures the device.

     -v   Be more verbose listing the snapshot devices.

     -x   Unlink backup after the device is configured.

     If no action option is given, -c is assumed.


           fssconfig fss0 /usr /tmp/back

     Configures the snapshot device fss0 for a snapshot of the /usr file sys-
     tem.  Data written through /usr will be backed up in /tmp/back.

           fssconfig fss1 / /dev/rsd0e 8192

     Configures the snapshot device fss1 for a snapshot of the / file system.
     Data written through / will be backed up in /dev/rsd0e.  The backup will
     take place in units of 8192 bytes.

           fssconfig -u fss0

     Unconfigures the fss0 device.

     opendisk(3), fss(4), mount(8), umount(8)

     The fssconfig command appeared in NetBSD 2.0.

     The fss(4) driver is experimental.  Be sure you have a backup before you
     use it.

NetBSD 5.0.1                   January 31, 2005                   NetBSD 5.0.1

You can also request any man page by name and (optionally) by section:


Use the DEFAULT collection to view manual pages for third-party software.

©1994 Man-cgi 1.15, Panagiotis Christias
©1996-2018 Modified for NetBSD by Kimmo Suominen