`vmbackup` creates VictoriaMetrics data backups from [instant snapshots](https://github.com/VictoriaMetrics/VictoriaMetrics/blob/master/README.md#how-to-work-with-snapshots).
* Local filesystem. Example: `fs://</absolute/path/to/backup>`
Incremental backups and full backups are supported. Incremental backups are created automatically if the destination path already contains data from the previous backup.
Full backups can be sped up with `-origin` pointing to already existing backup on the same remote storage. In this case `vmbackup` makes server-side copy for the shared
data between the existing backup and new backup. This saves time and costs on data transfer.
Backup process can be interrupted at any time. It is automatically resumed from the interruption point when restarting `vmbackup` with the same args.
Backed up data can be restored with [vmrestore](https://github.com/VictoriaMetrics/VictoriaMetrics/blob/master/app/vmrestore/README.md).
### Use cases
#### Regular backups
Regular backup can be performed with the following command:
*`</path/to/victoria-metrics-data>` - path to VictoriaMetrics data pointed by `-storageDataPath` command-line flag in single-node VictoriaMetrics or in cluster `vmstorage`.
There is no need to stop VictoriaMetrics for creating backups, since they are performed from immutable [instant snapshots](https://github.com/VictoriaMetrics/VictoriaMetrics/blob/master/README.md#how-to-work-with-snapshots).
*`<local-snapshot>` is the snapshot to backup. See [how to create instant snapshots](https://github.com/VictoriaMetrics/VictoriaMetrics/blob/master/README.md#how-to-work-with-snapshots).
*`<bucket>` is already existing name for [GCS bucket](https://cloud.google.com/storage/docs/creating-buckets).
*`<path/to/new/backup>` is the destination path where new backup will be placed.
#### Regular backups with server-side copy from existing backup
If the destination GCS bucket already contains the previous backup at `-origin` path, then new backup can be sped up
Where `<latest-snapshot>` is the latest [snapshot](https://github.com/VictoriaMetrics/VictoriaMetrics/blob/master/README.md#how-to-work-with-snapshots).
The command will upload only changed data to `gcs://<bucket>/latest`.
Where `<daily-snapshot>` is the snapshot for the last day `<YYYYMMDD>`.
This apporach saves network bandwidth costs on hourly backups (since they are incremental) and allows recovering data from either the last hour (`latest` backup)
or from any day (`YYYYMMDD` backups). Note that hourly backup shouldn't run when creating daily backup.
Do not forget removing old snapshots and backups when they are no longer needed for saving storage costs.
### How does it work?
The backup algorithm is the following:
1. Collect information about files in the `-snapshotName`, in the `-dst` and in the `-origin`.
2. Determine files in `-dst`, which are missing in `-snapshotName`, and delete them. These are usually small files, which are already merged into bigger files in the snapshot.
3. Determine files from `-snapshotName`, which are missing in `-dst`. These are usually small new files and bigger merged files.
4. Determine files from step 3, which exist in the `-origin`, and perform server-side copy of these files from `-origin` to `-dst`.
This are usually the biggest and the oldest files, which are shared between backups.
5. Upload the remaining files from setp 3 from `-snapshotName` to `-dst`.
The algorithm splits source files into 100MB chunks in the backup. Each chunk is stored as a separate file in the backup.
Such splitting minimizes the amounts of data to re-transfer after temporary errors.
`vmbackup` relies on [instant snapshot](https://medium.com/@valyala/how-victoriametrics-makes-instant-snapshots-for-multi-terabyte-time-series-data-e1f3fb0e0282) properties:
- All the files in the snapshot are immutable.
- Old files are periodically merged into new files.
- Smaller files have higher probability to be merged.
- Consecutive snapshots share many identical files.
These properties allow performing fast and cheap incremental backups and server-side copying from `-origin` paths.
`vmbackup` can work improperly or slowly when these properties are violated.
### Troubleshooting
* If the backup is slow, then try setting higher value for `-concurrency` flag. This will increase the number of concurrent workers that upload data to backup storage.
Path to file with GCS or S3 credentials. Credentials are loaded from default locations if not set.
See https://cloud.google.com/iam/docs/creating-managing-service-account-keys and https://docs.aws.amazon.com/general/latest/gr/aws-security-credentials.html
Where to put the backup on the remote storage. Example: gcs://bucket/path/to/backup/dir, s3://bucket/path/to/backup/dir or fs:///path/to/local/backup/dir
-dst can point to the previous backup. In this case incremental backup is performed, i.e. only changed data is uploaded
-loggerLevel string
Minimum level of errors to log. Possible values: INFO, ERROR, FATAL, PANIC (default "INFO")
