NAME
fssconfig —
configure file system
snapshot devices
SYNOPSIS
fssconfig |
[-cxv]
device path
backup
[cluster
[size]] |
fssconfig |
-l [-v]
[device] |
DESCRIPTION
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. Persistent 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 system 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 snapshot. 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.
FILES
- /dev/rfss?
-
- /dev/fss?
-
EXAMPLES
fssconfig fss0 /usr /tmp/back
mount /dev/fss0 /mnt
Configures the snapshot device
fss0 as a snapshot of the
/usr file system, 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.
SEE ALSO
opendisk(3),
fss(4),
dump(8),
mount(8),
umount(8)
HISTORY
The
fssconfig command appeared in
NetBSD
2.0.