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FSSCONFIG(8) NetBSD System Manager's Manual FSSCONFIG(8)
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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 the file system mounted on path, allowing device to be
accessed as though it were a disk.
If backup resides on the snapshotted file system a persistent snapshot
will be created. This snapshot is active until backup is unlinked. Per-
sistent snapshots save the file system as if it had been unmounted.
Unlinked but open files get removed from the snapshot. The time needed
to create a persistent snapshot increases with the size of the file sys-
tem and decreases with the file system block size. This snapshot mode is
only supported for FFS file 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
bytes. The snapshot is an image of the underlying block device at a
moment in time. Unlinked but open files are still present on the snap-
shot. The time needed to create a snapshot is independent of the size of
the file system or the file system block size.
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
mount /dev/fss0 /mnt
Configures the snapshot device fss0 as a snapshot of the /usr file sys-
tem, and makes the contents of the snapshot available via /mnt. Data
written through /usr will be backed up in /tmp/back.
fssconfig fss1 / /dev/rsd0e 8192
Configures the snapshot device fss1 as 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), dump(8), mount(8), umount(8)
The fssconfig command appeared in NetBSD 2.0.
NetBSD 9.3 July 29, 2016 NetBSD 9.3