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Policy

Design backup policy according to your needs.

WHEN: Backup Policy
WHERE: Backup Repo
HOW: Backup Method

WHEN

The first problem is WHEN to backup your database — Trade off between backup frequency and recovery time. Since you’ll need to replay the WAL logs to your recovery target since the last previous backup, the more frequent you backup, the less WAL logs you’ll need to replay, and the faster your recovery will be.

Everyday Full Backup

For a production database, it is recommended to start with the simplest everyday full backup policy. Where is the default backup policy in pigsty, implemented with crontab.

node_crontab: [ '00 01 * * * postgres /pg/bin/pg-backup full' ]
pgbackrest_method: local          # choose the backup repo method, `local` or `minio` or any other user defined repo
pgbackrest_repo:                  # pgbackrest repo: https://pgbackrest.org/configuration.html#section-repository
  local:                          # default pgbackrest repo with local posix fs
    path: /pg/backup              # local backup directory, `/pg/backup` by default
    retention_full_type: count    # retention full backups by count
    retention_full: 2             # keep 2, at most 3 full backups when using local fs repo

When using with the default local filesystem backup repo, it provides a 24~48h recovery window.

Let’s assume your database size is 100GB, and 10GB writes per day, and your backup size will be.

It will consume 2 ~ 3x of your database size, plus a 2 day’s WAL. So in practice, you may have to prepare a backup disk with at least 3 ~ 5x of your database size to use the default backup policy.

Full + Incr Backup

You can optimize backup space usage by changing these parameters.

If you are using MinIO / S3 as centralized backup repo, you can use more space than your disk limitation. Then consider the full + incr backup with 2-week retention policy:

node_crontab:  # make a full backup on monday 1am, and an incremental backup during weekdays
  - '00 01 * * 1 postgres /pg/bin/pg-backup full'
  - '00 01 * * 2,3,4,5,6,7 postgres /pg/bin/pg-backup'
pgbackrest_method: minio
pgbackrest_repo:                  # pgbackrest repo: https://pgbackrest.org/configuration.html#section-repository
  minio:                          # optional minio repo for pgbackrest
    type: s3                      # minio is s3-compatible, so s3 is used
    s3_endpoint: sss.pigsty       # minio endpoint domain name, `sss.pigsty` by default
    s3_region: us-east-1          # minio region, us-east-1 by default, useless for minio
    s3_bucket: pgsql              # minio bucket name, `pgsql` by default
    s3_key: pgbackrest            # minio user access key for pgbackrest
    s3_key_secret: S3User.Backup  # minio user secret key for pgbackrest
    s3_uri_style: path            # use path style uri for minio rather than host style
    path: /pgbackrest             # minio backup path, default is `/pgbackrest`
    storage_port: 9000            # minio port, 9000 by default
    storage_ca_file: /etc/pki/ca.crt  # minio ca file path, `/etc/pki/ca.crt` by default
    block: y                      # Enable block incremental backup
    bundle: y                     # bundle small files into a single file
    bundle_limit: 20MiB           # Limit for file bundles, 20MiB for object storage
    bundle_size: 128MiB           # Target size for file bundles, 128MiB for object storage
    cipher_type: aes-256-cbc      # enable AES encryption for remote backup repo
    cipher_pass: pgBackRest       # AES encryption password, default is 'pgBackRest'
    retention_full_type: time     # retention full backup by time on minio repo
    retention_full: 14            # keep full backup for the last 14 days

When using with the built-in minio filesystem backup repo, it provides a guaranteed 1-week pitr window.

Let’s assume your database size is 100GB, and 10GB writes per day, and your backup size will be like:

Where

By default, Pigsty has two default backup repo definition: the local and minio backup repo.

local: The default, use the local /pg/backup dir (Softlink point to pg_fs_backup: /data/backups)
minio: Use the SNSD 1-node MinIO cluster (Supported by pigsty, but not enabled by default)

pgbackrest_method: local          # choose the backup repo method, `local` or `minio` or any other user defined repo
pgbackrest_repo:                  # pgbackrest repo: https://pgbackrest.org/configuration.html#section-repository
  local:                          # default pgbackrest repo with local posix fs
    path: /pg/backup              # local backup directory, `/pg/backup` by default
    retention_full_type: count    # retention full backups by count
    retention_full: 2             # keep 2, at most 3 full backups when using local fs repo
  minio:                          # optional minio repo for pgbackrest
    type: s3                      # minio is s3-compatible, so s3 is used
    s3_endpoint: sss.pigsty       # minio endpoint domain name, `sss.pigsty` by default
    s3_region: us-east-1          # minio region, us-east-1 by default, useless for minio
    s3_bucket: pgsql              # minio bucket name, `pgsql` by default
    s3_key: pgbackrest            # minio user access key for pgbackrest
    s3_key_secret: S3User.Backup  # minio user secret key for pgbackrest
    s3_uri_style: path            # use path style uri for minio rather than host style
    path: /pgbackrest             # minio backup path, default is `/pgbackrest`
    storage_port: 9000            # minio port, 9000 by default
    storage_ca_file: /etc/pki/ca.crt  # minio ca file path, `/etc/pki/ca.crt` by default
    block: y                      # Enable block incremental backup
    bundle: y                     # bundle small files into a single file
    bundle_limit: 20MiB           # Limit for file bundles, 20MiB for object storage
    bundle_size: 128MiB           # Target size for file bundles, 128MiB for object storage
    cipher_type: aes-256-cbc      # enable AES encryption for remote backup repo
    cipher_pass: pgBackRest       # AES encryption password, default is 'pgBackRest'
    retention_full_type: time     # retention full backup by time on minio repo
    retention_full: 14            # keep full backup for the last 14 days