ZFS Tools

Various scripts for administrating ZFS. Modeled after time-sliderd and ZFS Automatic Snapshots from OpenSolaris

Setup

Install the gem.

Production version

gem install zfstools

Development version

rake install

Setup crontab entries for scripts wanted. See below.

Scripts

zfs-auto-snapshot

This will handle automatically snapshotting datasets similar to time-sliderd from OpenSolaris. Setup allows you to define your own intervals, snapshot names, and how many to keep for each interval. Zero-sized snapshots will automatically be cleaned up.

Usage

/usr/local/bin/zfs-auto-snapshot INTERVAL KEEP

• INTERVAL - The interval for the snapshot. This is something such as frequent, hourly, daily, weekly, monthly, etc.
• KEEP - How many to keep for this INTERVAL. Older ones will be destroyed.

Crontab

15,30,45 * * * * root /usr/local/bin/zfs-auto-snapshot frequent  4
0        * * * * root /usr/local/bin/zfs-auto-snapshot hourly   24
7        0 * * * root /usr/local/bin/zfs-auto-snapshot daily     7
14       0 * * 7 root /usr/local/bin/zfs-auto-snapshot weekly    4
28       0 1 * * root /usr/local/bin/zfs-auto-snapshot monthly  12

Dataset setup

Only datasets with the com.sun:auto-snapshot property set to true will be snapshotted.

zfs set com.sun:auto-snapshot=true DATASET

MySQL Support

Setting a MySQL dataset's property to mysql will hook it into the zfs-snapshot-mysql script. See its section for setup instructions.

zfs set com.sun:auto-snapshot=mysql DATASET

PostgreSQL Support

Setting a PostgreSQL dataset's property to postgresql will cause zfs-auto-snapshot to put postgresql in online backup mode for the snapshot.

zfs set com.sun:auto-snapshot=postgresql DATASET

The user executing zfs-auto-snapshot will require passwordless login to the postgres database and will require either REPLICATION or SUPERUSER privileges. The easiest approach is to set up a trust or ident record in your pg_hba.conf. The zfs-auto-snapshot script will execute pg_start_backup() prior to saving the snapshot and execute pg_stop_backup() afterwards.

Overrides

You can override a child dataset to use, or not use auto snapshotting by settings its flag with the given interval.

zfs set com.sun:auto-snapshot:weekly=false DATASET

zfs-snapshot-mysql

Snapshots a mysql server's databases. This requires that mysql's datadir/innodb_data_home_dir/innodb_log_group_home_dir be a ZFS dataset.

Example MySQL+ZFS Setup

Datasets

tank/db/mysql
tank/db/mysql/bin-log
tank/db/mysql/data
tank/db/mysql/innodb
tank/db/mysql/innodb/data
tank/db/mysql/innodb/log

ZFS Settings

These settings should be set before importing any data.

zfs set primarycache=metadata tank/db/mysql/innodb
zfs set recordsize=16K tank/db/mysql/innodb/data
zfs set recordsize=8K tank/db/mysql/data
zfs set compression=lzjb tank/db/mysql/data

MySQL Settings

innodb_data_home_dir = /tank/db/mysql/innodb/data
innodb_log_group_home_dir = /tank/db/mysql/innodb/log
datadir = /tank/db/mysql/data
log-bin = /tank/db/mysql/bin-log/mysql-bin

Script Usage

Setup a /root/.my.cnf with the relevant information on where to connect to, with the proper username/password that has access to FLUSH LOGS and FLUSH TABLES WITH READ LOCK. The zfs-auto-snapshot script will automatically flush the tables before saving the snapshots.

zfs-cleanup-snapshots

Cleans up zero-sized snapshots. This ignores snapshots created by zfs-auto-snapshot as it handles zero-sized in its own special way.

Usage

Crontab

*/20 * * * * /usr/local/bin/zfs-cleanup-snapshots