snapm 0.4.2

Snapshot Manager

Snapm

Snapshot manager (snapm) is a tool for managing sets of snapshots on Linux systems. The snapm tool allows snapshots of multiple volumes to be captured at the same time, representing the system state at the time the set was created.

The tool has a modular plugin architecture allowing different snapshot backends to be used together. Currently snapshots using LVM2 copy-on-write and thinly provisioned snapshots are supported.

• Snapm
  • Reporting bugs
  • Building and installing Snapm
    • Building an RPM package
  • The snapm command
    • Snapshot sets
    • Snapm subcommands
      • snapset
        • create
        • delete
        • rename
        • revert
        • resize
        • split
        • activate
        • deactivate
        • autoactivate
        • list
        • show
      • snapshot
        • activate
        • deactivate
        • autoactivate
        • list
        • show
      • plugin
        • list
    • Reporting commands
    • Getting help
  • Patches and pull requests
  • Documentation
  • License

Snapm aims to be a simple and extensible, and to be able to create snapshots for a wide range of Linux system configurations.

This project is hosted at:

• http://github.com/snapshotmanager/snapm

For the latest version, to contribute, and for more information, please visit the project pages.

To clone the current main (development) branch run:

git clone git://github.com/snapshotmanager/snapm.git

Reporting bugs

Please report bugs by opening an issue in the GitHub Issue Tracker

Building and installing Snapm

A setuptools based build script is provided: local installations and package builds can be performed by running python setup.py and a setup command. See python setup.py --help for detailed information on the available options and commands.

The snapm command uses the boom boot manager to manage boot entries for the snapshots that it creates. If installing snapm manually, Install boom first: either from your distribution repositories or the upstream Git repo. Snapshot manager is tested with boom-1.6.4 and later.

Building an RPM package

A spec file is included in the repository that can be used to build RPM packages of snapm. The packit service is also enabled for new pull requests and will automatically build packages for fedora-stable, fedora-development, epel-9, centos-stream-9, and centos-stream-10.

The snapm command

The snapm command is the main interface to the snapshot manager. It is able to create, delete, and display snapshots and snapshot sets and provides reports listing the snapshots and snapshot sets available on the system.

Snapm commands normally operate on a particular object type: a snapshot set or an individual snapshot.

# snapm snapset <command> <options> # `snapset` command

# snapm snapshot <command> <options> # `snapshot` command

Snapshot sets

Snapshot manager groups snapshots taken at the same moment in time into a named "snapshot set", or snapset. This allows the snapshots to be managed as a single unit and simplifies the management of snapshots of multiple volumes. Each snapshot set must contain at least one snapshot.

Snapm subcommands

snapset

The snapset subcommand is used to create, delete, rename, activate, deactivate, list and display snapsets.

create

Create a new snapset with the provided name and list of sources (mount point or block device paths):

# snapm snapset create [-b|--bootable] [-r|--revert] <name> source...

Size Policies

Size policies can be used to control the size of fixed-sized snapshots and to check for available space when creating a snapshot set.

Some snapshot implementations (Lvm2CoW) require a fixed size to be specified for the snapshot backstore when the snapshot is created. The default size allocated by snapshot manager is 2x the current file system usage, allowing the existing content of the volume to be overwritten twice before exhausting the snapshot space.

Plugins for snapshot providers that do not require a fixed snapshot size will check that space is available for the requested size policy at snapshot set creation time.

Size policy hints can be manually given on the command line to override the default behavior on a per-source path basis. Four policies are available:

• FIXED - a fixed size given on the command line
• FREE - a percentage fraction of the free space available
• USED - a percentage fraction of the space currently used on the mount point (may be greater than 100%)
• SIZE - a percentage fraction of the origin device size from 0 to 100%

The FIXED size policy accepts optional units of KiB, MiB, GiB, TiB, PiB, EiB and ZiB. Units may be abbreviated to the first character.

The USED size policy can only be applied to mounted file systems.

Per-source path size policies are specified by adding a ':' and the required policy to the corresponding mount point path, for example:

# snapm snapset create backup /:2G /var:1G /home

# snapm snapset create backup /:25%FREE /var:25%FREE /home

# snapm snapset create backup /:100%USED /var:100%USED /home

# snapm snapset create backup /:100%SIZE /var:100%SIZE /home

If no size policy is specified the default is 200%USED for mounted file systems and 25%SIZE for unmounted block devices. To ensure a volume can be completely overwritten specify 100%SIZE. This requires more storage capacity but avoids the possibility of the snapshot running out of space.

A default size policy for all source paths that do not specify an explicit per-path policy can be set with the --size-policy argument:

# snapm snapset create backup --size-policy 100%SIZE / /home /var

On success the snapm snapset create command displays the newly created snapshot set on stdout:

# snapm snapset create -br --size-policy 100%USED backup / /home /var
SnapsetName:      backup
Sources:          /, /home, /var
NrSnapshots:      3
Time:             2024-12-05 19:10:44
UUID:             d3f5e3cd-a383-5dba-b597-9134a2c426e9
Status:           Active
Autoactivate:     yes
Bootable:         yes
BootEntries:
  SnapshotEntry:  f574a20
  RevertEntry:    f428f9f

delete

Delete an existing snapset by name or uuid.

# snapm snapset delete <name|uuid>

rename

Rename an existing snapset.

# snapm snapset rename <old_name> <new_name>

revert

Revert an existing snapset, re-setting the content of the origin volumes to the state they were in at the time the snapset was created. The snapset to be reverted may be specified either by its name or uuid.

# snapm snapset revert <name|uuid>

If the origins of the snapshot set are in use at the time of the revert the operation is deferred until the next time the snapshot set is activated (for example during a reboot). If a revert boot entry was created for the snapshot set the revert command will suggest booting into it to continue:

# snapm snapset revert upgrade
WARNING - Snaphot set upgrade origin is in use: reboot required to complete revert
Boot into 'Revert upgrade 2024-06-10 15:25:15 (6.8.9-300.fc40.x86_64)' to continue

resize

Resize the members on an existing snapset, applying a new size policy to specified sources or applying a new default size policy to all snapshots within a snapset.

Resize the /var member of the snapshot set named upgrade to 100%SIZE:

# snapm snapset resize upgrade /var:100%SIZE

Resize each member of the snapshot set named backup to the 200%USED size policy:

# snapm snapset resize backup --size-policy 200%USED

split

Split snapshots from an existing snapshot set into a new snapshot set.

Split the snapshot set named 'name' into a new snapshot set named 'new_name'. Each listed source from 'name' is split into the new snapshot set. Sources that are not listed on the command line remain part of the original snapshot set. It is an error to split all sources from a snapshot set: in this case use 'snapm snapset rename' instead.

To split the source "/home" from the existing snapshot set "upgrade" into a new snapshot set named "noupgrade":

# snapm snapset split upgrade noupgrade /home
SnapsetName:      noupgrade
Sources:          /home
NrSnapshots:      1
Time:             2025-03-31 20:21:29
UUID:             30e69b86-5c48-5e5d-be1a-bf3d63aef8f7
Status:           Inactive
Autoactivate:     no
Bootable:         no

activate

Activate the members of an existing snapset, or all snapsets if no name or uuid argument is given.

# snapm snapset activate [<name|uuid>]

deactivate

Deactivate the members of an existing snapset, or all snapsets if no name or uuid argument is given.

# snapm snapset deactivate [<name|uuid>]

autoactivate

Enable or disable autoactivation for the snapshots in a snapshot set.

# snapm snapset autoactivate [--yes|--no] [<name|uuid>]

list

List available snapsets matching selection criteria.

# snapm snapset list [<name|uuid>]

By default the information is presented as a tabular report with column headings indicating the meaning of each value. The default column selection includes the SnapsetName, Time, NrSnapshots, Status, and MountPoints fields:

# snapm snapset list
SnapsetName  Time                 NrSnapshots Status  Sources
backup       2024-12-05 19:14:03            3 Active  /, /home, /var
upgrade      2024-12-05 19:14:09            2 Active  /, /var

Custom field specifications may be given with the -o/--options argument. To obtain a list of available fields run snapm snapset list -o+help:

# snapm snapset list -o+help
Snapshot set Fields
-------------------
  name         - Snapshot set name [str]
  uuid         - Snapshot set UUID [uuid]
  timestamp    - Snapshot set creation time as a UNIX epoch value [num]
  time         - Snapshot set creation time [time]
  nr_snapshots - Number of snapshots [num]
  sources      - Snapshot set sources [strlist]
  mountpoints  - Snapshot set mount points [strlist]
  devices      - Snapshot set devices [strlist]
  status       - Snapshot set status [str]
  autoactivate - Autoactivation status [str]
  bootable     - Configured for snapshot boot [str]
  bootentry    - Snapshot set boot entry [sha]
  revertentry  - Snapshot set revert boot entry [sha]

To specify custom fields pass a comma separated list to -o:

# snapm snapset list -oname,time
SnapsetName  Time
backup       2024-12-05 19:14:03
upgrade      2024-12-05 19:14:09

To add fields to the default field set prefix the list of fields with the + character:

# snapm snapset list -o+bootentry,revertentry
SnapsetName  Time                 NrSnapshots Status  Sources        SnapshotEntry RevertEntry
backup       2024-12-05 19:14:03            3 Active  /, /home, /var 41573a414f9d5 1cc5bc59c9b90
upgrade      2024-12-05 19:14:09            2 Active  /, /var        a60dab4d3fb36 4ce6b27f16f30

The report can also be produced in JSON notation, suitable for parsing by other tools using the --json argument:

# snapm snapset list --json
{
    "Snapsets": [
        {
            "snapset_name": "backup",
            "snapset_time": "2024-12-05 19:14:03",
            "snapset_nr_snapshots": 3,
            "snapset_status": "Active",
            "snapset_sources": [
                "/",
                "/home",
                "/var"
            ]
        },
        {
            "snapset_name": "upgrade",
            "snapset_time": "2024-12-05 19:14:09",
            "snapset_nr_snapshots": 2,
            "snapset_status": "Active",
            "snapset_sources": [
                "/",
                "/var"
            ]
        }
    ]
}

For further report formatting options refer to the snapm(8) manual page.

show

Display available snapsets matching selection criteria.

# snapm snapset show [<name|uuid>]

By default the output is formatted in the same way as the output of the snapm snapset create command:

# snapm snapset show upgrade
SnapsetName:      upgrade
Sources:          /, /var
NrSnapshots:      2
Time:             2024-12-05 19:14:09
UUID:             87c6df8f-bd8c-5c9d-b081-4f6d6068cc07
Status:           Active
Autoactivate:     yes
Bootable:         yes
BootEntries:
  SnapshotEntry:  a60dab4
  RevertEntry:    4ce6b27

The individual snapshots making up each set are also displayed if --members is used:

# snapm snapset show --members
SnapsetName:      upgrade
Sources:          /, /var
NrSnapshots:      2
Time:             2024-12-05 19:19:30
UUID:             f0a46cde-9eed-5335-b239-66ed53e5b503
Status:           Active
Autoactivate:     yes
Bootable:         yes
BootEntries:
  SnapshotEntry:  dfce8d8
  RevertEntry:    fc414b0
Snapshots:
    Name:           fedora/root-snapset_upgrade_1733426370_-
    SnapsetName:    upgrade
    Origin:         /dev/fedora/root
    Time:           2024-12-05 19:19:30
    Source:         /
    MountPoint:     /
    Provider:       lvm2-cow
    UUID:           7566dde3-96f4-5288-8b15-18be7c520327
    Status:         Active
    Size:           8.8GiB
    Free:           8.8GiB
    Autoactivate:   yes
    DevicePath:     /dev/fedora/root-snapset_upgrade_1733426370_-
    VolumeGroup:    fedora
    LogicalVolume:  root-snapset_upgrade_1733426370_-

    Name:           fedora/var-snapset_upgrade_1733426370_-var
    SnapsetName:    upgrade
    Origin:         /dev/fedora/var
    Time:           2024-12-05 19:19:30
    Source:         /var
    MountPoint:     /var
    Provider:       lvm2-cow
    UUID:           22674f3e-f5c4-5632-9add-2df51985679e
    Status:         Active
    Size:           6.4GiB
    Free:           6.4GiB
    Autoactivate:   yes
    DevicePath:     /dev/fedora/var-snapset_upgrade_1733426370_-var
    VolumeGroup:    fedora
    LogicalVolume:  var-snapset_upgrade_1733426370_-var

The output is also available in JSON notation using the --json argument:

# snapm snapset show upgrade --json
[
    {
        "SnapsetName": "upgrade",
        "Sources": [
            "/",
            "/var"
        ],
        "MountPoints": [
            "/",
            "/var"
        ],
        "Devices": [],
        "NrSnapshots": 2,
        "Timestamp": 1733426370,
        "Time": "2024-12-05 19:19:30",
        "UUID": "f0a46cde-9eed-5335-b239-66ed53e5b503",
        "Status": "Active",
        "Autoactivate": true,
        "Bootable": true,
        "BootEntries": {
            "SnapshotEntry": "dfce8d8",
            "RevertEntry": "fc414b0"
        }
    }
]

The output is a JSON array of dictionaries describing each configured snapshot set.

Similarly for --members:

# snapm snapset show upgrade --members --json
[
    {
        "SnapsetName": "upgrade",
        "Sources": [
            "/",
            "/var"
        ],
        "MountPoints": [
            "/",
            "/var"
        ],
        "Devices": [],
        "NrSnapshots": 2,
        "Timestamp": 1733426370,
        "Time": "2024-12-05 19:19:30",
        "UUID": "f0a46cde-9eed-5335-b239-66ed53e5b503",
        "Status": "Active",
        "Autoactivate": true,
        "Bootable": true,
        "BootEntries": {
            "SnapshotEntry": "dfce8d8",
            "RevertEntry": "fc414b0"
        },
        "Snapshots": [
            {
                "Name": "fedora/root-snapset_upgrade_1733426370_-",
                "SnapsetName": "upgrade",
                "Origin": "/dev/fedora/root",
                "Timestamp": 1733426370,
                "Time": "2024-12-05 19:19:30",
                "Source": "/",
                "MountPoint": "/",
                "Provider": "lvm2-cow",
                "UUID": "7566dde3-96f4-5288-8b15-18be7c520327",
                "Status": "Active",
                "Size": "8.8GiB",
                "Free": "8.8GiB",
                "SizeBytes": 9474932736,
                "FreeBytes": 9473985242,
                "Autoactivate": true,
                "DevicePath": "/dev/fedora/root-snapset_upgrade_1733426370_-"
            },
            {
                "Name": "fedora/var-snapset_upgrade_1733426370_-var",
                "SnapsetName": "upgrade",
                "Origin": "/dev/fedora/var",
                "Timestamp": 1733426370,
                "Time": "2024-12-05 19:19:30",
                "Source": "/var",
                "MountPoint": "/var",
                "Provider": "lvm2-cow",
                "UUID": "22674f3e-f5c4-5632-9add-2df51985679e",
                "Status": "Active",
                "Size": "6.4GiB",
                "Free": "6.4GiB",
                "SizeBytes": 6891241472,
                "FreeBytes": 6890552347,
                "Autoactivate": true,
                "DevicePath": "/dev/fedora/var-snapset_upgrade_1733426370_-var"
            }
        ]
    }
]

snapshot

The snapshot command is used to manipulate, list, and display snapshots.

snapshot activate

Activate individual snapshots matching selection criteria.

# snapm snapshot activate [-N name] [-U uuid] [<name|uuid>]

snapshot deactivate

Deactivate individual snapshots matching selection criteria.

# snapm snapshot deactivate [-N name] [-U uuid] [<name|uuid>]

snapshot autoactivate

Enable or disable autoactivation for individual snapshots matching selection criteria.

# snapm snapshot autoactivate [--yes|--no] [-N name] [-U uuid] [<name|uuid>]

snapshot list

List available snapshots matching selection criteria.

# snapm snapshot list [<name|uuid>]

By default the information is presented as a tabular report with column headings indicating the meaning of each value. The default column selection includes the SnapsetName, Name, Origin, MountPoint, Status, Size, Free, Autoactivate, and Provider fields:

# snapm snapshot list
SnapsetName  Name                                         Origin           Source  Status  Size   Free   Autoactivate Provider
upgrade      fedora/root-snapset_upgrade_1733426499_-     /dev/fedora/root /       Active  8.8GiB 8.8GiB yes          lvm2-cow
upgrade      fedora/var-snapset_upgrade_1733426499_-var   /dev/fedora/var  /var    Active  6.4GiB 6.4GiB yes          lvm2-cow
upgrade      fedora/home-snapset_upgrade_1733426499_-home /dev/fedora/home /home   Active  1.0GiB 1.9GiB yes          lvm2-thin

Custom field specifications may be given with the -o/--options argument. To obtain a list of available fields run snapm snapset list -o+help:

# snapm snapshot list -o+help
Snapshot Fields
---------------
  name         - Snapshot name [str]
  uuid         - Snapshot UUID [uuid]
  origin       - Origin [str]
  source       - Snapshot source [str]
  mountpoint   - Snapshot mount point [str]
  devpath      - Snapshot device path [str]
  provider     - Snapshot provider plugin [str]
  status       - Snapshot status [str]
  size         - Snapshot size [size]
  free         - Free space available [size]
  size_bytes   - Snapshot size in bytes [num]
  free_bytes   - Free space available in bytes [num]
  autoactivate - Autoactivation status [str]

Snapshot set Fields
-------------------
  name         - Snapshot set name [str]
  uuid         - Snapshot set UUID [uuid]
  timestamp    - Snapshot set creation time as a UNIX epoch value [num]
  time         - Snapshot set creation time [time]
  nr_snapshots - Number of snapshots [num]
  sources      - Snapshot set sources [strlist]
  mountpoints  - Snapshot set mount points [strlist]
  devices      - Snapshot set devices [strlist]
  status       - Snapshot set status [str]
  autoactivate - Autoactivation status [str]
  bootable     - Configured for snapshot boot [str]
  bootentry    - Snapshot set boot entry [sha]
  revertentry  - Snapshot set revert boot entry [sha]

To specify custom fields pass a comma separated list to -o:

# snapm snapshot list -osnapset_name,status,devpath
SnapsetName  Status  DevicePath
upgrade      Active  /dev/fedora/root-snapset_upgrade_1733426499_-
upgrade      Active  /dev/fedora/var-snapset_upgrade_1733426499_-var
upgrade      Active  /dev/fedora/home-snapset_upgrade_1733426499_-home

To add fields to the default field set prefix the list of fields with the + character:

# snapm snapshot list -o+devpath
SnapsetName  Name                                         Origin           Source  Status  Size   Free   Autoactivate Provider  DevicePath
upgrade      fedora/root-snapset_upgrade_1733426499_-     /dev/fedora/root /       Active  8.8GiB 8.8GiB yes          lvm2-cow  /dev/fedora/root-snapset_upgrade_1733426499_-
upgrade      fedora/var-snapset_upgrade_1733426499_-var   /dev/fedora/var  /var    Active  6.4GiB 6.4GiB yes          lvm2-cow  /dev/fedora/var-snapset_upgrade_1733426499_-var
upgrade      fedora/home-snapset_upgrade_1733426499_-home /dev/fedora/home /home   Active  1.0GiB 1.9GiB yes          lvm2-thin /dev/fedora/home-snapset_upgrade_1733426499_-home

The report can also be produced in JSON notation, suitable for parsing by other tools using the --json argument:

# snapm snapshot list --json
{
    "Snapshots": [
        {
            "snapset_name": "upgrade",
            "snapshot_name": "fedora/root-snapset_upgrade_1733426499_-",
            "snapshot_origin": "/dev/fedora/root",
            "snapshot_source": "/",
            "snapshot_status": "Active",
            "snapshot_size": "8.8GiB",
            "snapshot_free": "8.8GiB",
            "snapshot_autoactivate": true,
            "snapshot_provider": "lvm2-cow"
        },
        {
            "snapset_name": "upgrade",
            "snapshot_name": "fedora/var-snapset_upgrade_1733426499_-var",
            "snapshot_origin": "/dev/fedora/var",
            "snapshot_source": "/var",
            "snapshot_status": "Active",
            "snapshot_size": "6.4GiB",
            "snapshot_free": "6.4GiB",
            "snapshot_autoactivate": true,
            "snapshot_provider": "lvm2-cow"
        },
        {
            "snapset_name": "upgrade",
            "snapshot_name": "fedora/home-snapset_upgrade_1733426499_-home",
            "snapshot_origin": "/dev/fedora/home",
            "snapshot_source": "/home",
            "snapshot_status": "Active",
            "snapshot_size": "1.0GiB",
            "snapshot_free": "1.9GiB",
            "snapshot_autoactivate": true,
            "snapshot_provider": "lvm2-thin"
        }
    ]
}

For further report formatting options refer to the snapm(8) manual page.

snapshot show

Display available snapshots matching selection criteria.

# snapm snapshot show [<name|uuid>]

By default the output is formatted in the same way as the output of the snapm snapset show --members command:

# snapm snapshot show
Name:           fedora/root-snapset_upgrade_1733426499_-
SnapsetName:    upgrade
Origin:         /dev/fedora/root
Time:           2024-12-05 19:21:39
Source:         /
MountPoint:     /
Provider:       lvm2-cow
UUID:           6883146c-38e8-50a7-ac37-c2e9e809bb10
Status:         Active
Size:           8.8GiB
Free:           8.8GiB
Autoactivate:   yes
DevicePath:     /dev/fedora/root-snapset_upgrade_1733426499_-
VolumeGroup:    fedora
LogicalVolume:  root-snapset_upgrade_1733426499_-

Name:           fedora/var-snapset_upgrade_1733426499_-var
SnapsetName:    upgrade
Origin:         /dev/fedora/var
Time:           2024-12-05 19:21:39
Source:         /var
MountPoint:     /var
Provider:       lvm2-cow
UUID:           1a0ab3f1-f995-5c7b-846b-78189cf62e06
Status:         Active
Size:           6.4GiB
Free:           6.4GiB
Autoactivate:   yes
DevicePath:     /dev/fedora/var-snapset_upgrade_1733426499_-var
VolumeGroup:    fedora
LogicalVolume:  var-snapset_upgrade_1733426499_-var

Name:           fedora/home-snapset_upgrade_1733426499_-home
SnapsetName:    upgrade
Origin:         /dev/fedora/home
Time:           2024-12-05 19:21:39
Source:         /home
MountPoint:     /home
Provider:       lvm2-thin
UUID:           e8163739-b700-5ef8-974a-7da53eeaff04
Status:         Active
Size:           1.0GiB
Free:           1.9GiB
Autoactivate:   yes
DevicePath:     /dev/fedora/home-snapset_upgrade_1733426499_-home
VolumeGroup:    fedora
LogicalVolume:  home-snapset_upgrade_1733426499_-home

The output is also available in JSON notation using the --json argument:

# snapm snapshot show --json
[
    {
        "Name": "fedora/root-snapset_upgrade_1733426499_-",
        "SnapsetName": "upgrade",
        "Origin": "/dev/fedora/root",
        "Timestamp": 1733426499,
        "Time": "2024-12-05 19:21:39",
        "Source": "/",
        "MountPoint": "/",
        "Provider": "lvm2-cow",
        "UUID": "6883146c-38e8-50a7-ac37-c2e9e809bb10",
        "Status": "Active",
        "Size": "8.8GiB",
        "Free": "8.8GiB",
        "SizeBytes": 9474932736,
        "FreeBytes": 9473985242,
        "Autoactivate": true,
        "DevicePath": "/dev/fedora/root-snapset_upgrade_1733426499_-"
    },
    {
        "Name": "fedora/var-snapset_upgrade_1733426499_-var",
        "SnapsetName": "upgrade",
        "Origin": "/dev/fedora/var",
        "Timestamp": 1733426499,
        "Time": "2024-12-05 19:21:39",
        "Source": "/var",
        "MountPoint": "/var",
        "Provider": "lvm2-cow",
        "UUID": "1a0ab3f1-f995-5c7b-846b-78189cf62e06",
        "Status": "Active",
        "Size": "6.4GiB",
        "Free": "6.4GiB",
        "SizeBytes": 6891241472,
        "FreeBytes": 6890552347,
        "Autoactivate": true,
        "DevicePath": "/dev/fedora/var-snapset_upgrade_1733426499_-var"
    },
    {
        "Name": "fedora/home-snapset_upgrade_1733426499_-home",
        "SnapsetName": "upgrade",
        "Origin": "/dev/fedora/home",
        "Timestamp": 1733426499,
        "Time": "2024-12-05 19:21:39",
        "Source": "/home",
        "MountPoint": "/home",
        "Provider": "lvm2-thin",
        "UUID": "e8163739-b700-5ef8-974a-7da53eeaff04",
        "Status": "Active",
        "Size": "1.0GiB",
        "Free": "1.9GiB",
        "SizeBytes": 1073741824,
        "FreeBytes": 2079837914,
        "Autoactivate": true,
        "DevicePath": "/dev/fedora/home-snapset_upgrade_1733426499_-home"
    }
]

The output is a JSON array of dictionaries describing each configured snapshot.

plugin

The plugin command is used to display information on the available snapshot provider plugins.

plugin list

The plugin list command lists the available plugins:

# snapm plugin list
PluginName PluginVersion PluginType
lvm2-cow   0.1.0         Lvm2CowSnapshot
lvm2-thin  0.1.0         Lvm2ThinSnapshot
stratis    0.1.0         StratisSnapshot

Reporting commands

The snapm snapset list and snapm snapshot list commands generate a tabular report as output. To control the list of displayed fields use the -o/--options FIELDS argument:

# snapm snapset list -oname,sources
SnapsetName  Sources
backup       /, /home, /var
userdata     /data, /home

To add extra fields to the default selection, prefix the field list with the + character:

# snapm snapset list -o+uuid
SnapsetName  Time                 NrSnapshots Status   Sources        UUID
backup       2024-12-05 19:26:28            3 Active   /, /home, /var 53514020-e88d-5f53-bf09-42c6ab6e325d
userdata     2024-12-05 19:26:45            2 Inactive /data, /home   e8d58051-7a94-5802-8328-54661ab1a70f

To display the available fields for either report use the field name help.

snapset fields:

# snapm snapset list -o help
Snapshot set Fields
-------------------
  name         - Snapshot set name [str]
  uuid         - Snapshot set UUID [uuid]
  timestamp    - Snapshot set creation time as a UNIX epoch value [num]
  time         - Snapshot set creation time [time]
  nr_snapshots - Number of snapshots [num]
  sources      - Snapshot set sources [strlist]
  mountpoints  - Snapshot set mount points [strlist]
  devices      - Snapshot set devices [strlist]
  status       - Snapshot set status [str]
  autoactivate - Autoactivation status [str]
  bootable     - Configured for snapshot boot [str]
  bootentry    - Snapshot set boot entry [sha]
  revertentry  - Snapshot set revert boot entry [sha]

snapshot fields:

# snapm snapshot list -o help
Snapshot Fields
---------------
  name         - Snapshot name [str]
  uuid         - Snapshot UUID [uuid]
  origin       - Origin [str]
  source       - Snapshot source [str]
  mountpoint   - Snapshot mount point [str]
  devpath      - Snapshot device path [str]
  provider     - Snapshot provider plugin [str]
  status       - Snapshot status [str]
  size         - Snapshot size [size]
  free         - Free space available [size]
  size_bytes   - Snapshot size in bytes [num]
  free_bytes   - Free space available in bytes [num]
  autoactivate - Autoactivation status [str]

Snapshot set Fields
-------------------
  name         - Snapshot set name [str]
  uuid         - Snapshot set UUID [uuid]
  timestamp    - Snapshot set creation time as a UNIX epoch value [num]
  time         - Snapshot set creation time [time]
  nr_snapshots - Number of snapshots [num]
  sources      - Snapshot set sources [strlist]
  mountpoints  - Snapshot set mount points [strlist]
  devices      - Snapshot set devices [strlist]
  status       - Snapshot set status [str]
  autoactivate - Autoactivation status [str]
  bootable     - Configured for snapshot boot [str]
  bootentry    - Snapshot set boot entry [sha]
  revertentry  - Snapshot set revert boot entry [sha]

JSON reports

All reports can optionally be formatted as JSON for parsing by other tools using the --json argument:

# snapm plugin list --json
{
    "Plugins": [
        {
            "plugin_name": "lvm2-cow",
            "plugin_version": "0.1.0",
            "plugin_type": "Lvm2CowSnapshot"
        },
        {
            "plugin_name": "lvm2-thin",
            "plugin_version": "0.1.0",
            "plugin_type": "Lvm2ThinSnapshot"
        },
        {
            "plugin_name": "stratis",
            "plugin_version": "0.1.0",
            "plugin_type": "StratisSnapshot"
        }
    ]
}

Getting help

Help is available for the snapm command and each subcommand.

Run the command with --help to display the full usage message:

# snapm --help
usage: snapm [-h] [-d DEBUGOPTS] [-v] [-V] {snapset,snapshot,plugin} ...

Snapshot Manager

positional arguments:
  {snapset,snapshot,plugin}
                        Command type
    snapset             Snapshot set commands
    snapshot            Snapshot commands
    plugin              Plugin commands

options:
  -h, --help            show this help message and exit
  -d, --debug DEBUGOPTS
                        A list of debug options to enable
  -v, --verbose         Enable verbose output
  -V, --version         Report the version number of snapm

Subcommand help:

# snapm snapset --help
usage: snapm snapset [-h]
                     {create,delete,rename,resize,revert,activate,deactivate,autoactivate,list,show} ...

positional arguments:
  {create,delete,rename,resize,revert,activate,deactivate,autoactivate,list,show}
    create              Create snapshot sets
    delete              Delete snapshot sets
    rename              Rename a snapshot set
    resize              Resize snapshot sets
    revert              Revert snapshot sets
    activate            Activate snapshot sets
    deactivate          Deactivate snapshot sets
    autoactivate        Set autoactivation status for snapshot sets
    list                List snapshot sets
    show                Display snapshot sets

options:
  -h, --help            show this help message and exit

# snapm snapset create --help
usage: snapm snapset create [-h] [-s SIZE_POLICY] [-b] [-r]
                            SNAPSET_NAME SOURCE [SOURCE ...]

positional arguments:
  SNAPSET_NAME          The name of the snapshot set to create
  SOURCE                A device or mount point path to include in this
                        snapshot set

options:
  -h, --help            show this help message and exit
  -s, --size-policy SIZE_POLICY
                        A default size policy for fixed size snapshots
  -b, --bootable        Create a boot entry for this snapshot set
  -r, --revert          Create a revert boot entry for this snapshot set

Documentation

API documentation is automatically generated using Sphinx and Read the Docs.

Installation and user documentation will be added in a future update.

License

The snapm project is licensed under the the Apache license, version 2.0 (Apache-2.0):

https://www.apache.org/licenses/LICENSE-2.0