[](https://crates.io/crates/btm)
[](https://docs.rs/btm)
[](https://github.com/rust-util-collections/btm/actions/workflows/rust.yml)
[](https://github.com/rust-random/rand#rust-version-requirements)
# BTM
Blockchain Time Machine.
BTM is an incremental data backup mechanism that does not require downtime.
## Why would you need this?
btm will give you the following abilities or advantages:
- rollback to the state of a desired block height
- hot backup during operation, no downtime is needed
- based on OS-level infrastructure, stable and reliable
- very small resource usage, almost no performance damage
- ...
## Library Usages
```rust
use btm::{BtmCfg, SnapMode, SnapAlgo};
let cfg = BtmCfg {
itv: 10,
cap: 100,
mode: SnapMode::Zfs,
algo: SnapAlgo::Fade,
volume: "zroot/data".to_owned(),
};
// Generate snapshots in some threads.
cfg.snapshot(0).unwrap();
cfg.snapshot(1).unwrap();
cfg.snapshot(11).unwrap();
/// Print all existing snapshots.
cfg.list_snapshots();
/// Rollback to the state of the last snapshot.
cfg.rollback(None, false).unwrap();
/// Rollback to the state of a custom snapshot.
cfg.rollback(Some(11), true).unwrap();
```
## Binary Usages
```
Usage: btm <COMMAND>
Commands:
list List all existing snapshots
rollback Rollback to the state of an existing snapshot
clean Clean all or part of existing snapshots
daemon Run btm as a daemon process
help Print this message or the help of the given subcommand(s)
Options:
-h, --help Print help information
-V, --version Print version information
```
```
Usage: btm list [OPTIONS]
Options:
-p, --volume <VOLUME> The target volume to operate on, if $BTM_VOLUME is specified, this option can be omitted
-h, --help Print help information
```
```
Usage: btm rollback [OPTIONS]
Options:
-p, --volume <VOLUME> The target volume to operate on, if $BTM_VOLUME is specified, this option can be omitted
-s, --snapshot-id <SNAPSHOT_ID> The target snapshot to rollback to, a negative value means the latest snapshot [default: -1]
-S, --strict In this mode, if `snapshot_id` cannot be matched exactly, an error will be returned
-h, --help Print help information
```
```
Usage: btm clean [OPTIONS]
Options:
-p, --volume <VOLUME> The target volume to operate on, if $BTM_VOLUME is specified, this option can be omitted
-k, --kept <KEPT> How many snapshots should be kept [default: 0]
-h, --help Print help information
```
```
Usage: btm daemon [OPTIONS]
Options:
-p, --volume <VOLUME> The target volume to operate on, if $BTM_VOLUME is specified, this option can be omitted
-i, --itv <ITV> The interval between two adjacent snapshots [default: 10]
-c, --cap <CAP> The maximum number of snapshots to keep, older snapshots will be cleaned up [default: 100]
-m, --mode <MODE> Optional, `zfs` or `btrfs`, case insensitive, will try to automatically identify if not specified
-a, --algo <ALGO> fair or fade, case insensitive [default: Fair]
-h, --help Print help information
```
## Install as a 'systemd service'
**Steps:**
```shell
make
mv btm_package.tar.gz /tmp/
cd /tmp/
tar -xpf btm_package.tar.gz
cd btm_package
su # swith your user account to 'root'
./install.sh \
--snapshot-itv=4 \
--snapshot-cap=100 \
--snapshot-mode=zfs \
--snapshot-algo=fade \
--snapshot-volume=zfs/data
```
**Outputs of `systemctl status btm-daemon.service`:**
```
● btm-daemon.service - "btm daemon"
Loaded: loaded (/lib/systemd/system/btm-daemon.service; enabled; vendor preset: disabled)
Active: active (running) since Tue 2021-10-12 21:24:16 CST; 2min 27s ago
Main PID: 334 (btm)
Tasks: 1 (limit: 37805)
CPU: 1ms
CGroup: /system.slice/btm-daemon.service
└─334 /usr/local/bin/btm daemon -p=/data -i=4 -c=100 -m=btrfs -a=fade
```
**Usage of [tools/install.sh](./tools/install.sh):**
```
# tools/install.sh -h
Usage
install.sh
--snapshot-itv=<ITV>
--snapshot-cap=<CAP>
--snapshot-mode=<MODE>
--snapshot-algo=<ALGO>
--snapshot-volume=<VOLUME>
Example
install.sh \
--snapshot-itv=4 \
--snapshot-cap=100 \
--snapshot-mode=zfs \
--snapshot-algo=fair \
--snapshot-volume=zfs/blockchain
Example, short style
install.sh -i=4 -c=100 -m=zfs -a=fair -p=zfs/blockchain
install.sh -i=4 -c=100 -m=btrfs -a=fair -p=/data/blockchain
```