# zfsbk Overview This is a minimalistic utility to fully automate backups for systems using the outstanding [ZFS](http://en.wikipedia.org/wiki/ZFS) filesystem. It relies on Snapshots to provide: * local backups – they help you recover files from earlier in time. * remote backups – they help you recover whole datasets for system failures. ZFS snapshots are extremely lightweight on the system (actually cheaper to take snapshot than not!) and cheap on storage (only changed blocks are saved) and allow you to restore files from past versions. # The gist You run these tools from cron to periodically * take ZFS snapshots (`zfssnap.sh`) * serialize and export them remotely (`zfsbk.sh`) The tools take care of limiting the number of snapshots, so you do not have to periodically prune old snapshots. Snapshots can be named so you can create groups of them, e.g. "hourly snapshots", "newdeplo snapshots" and "exported snapshots". An additional tool takes care of exporting such snapshots, and uploading them to a remote server. # Installation Simply place all `*.sh` files of the package into directory `/usr/local/sbin/`. # Snapshot management You run `zfssnap.sh` for taking snapshots, typically from cron: vim /etc/crontab ... # take hourly snapshot, keep 24 of them @hourly root /usr/local/sbin/zfssnap.sh hour 24 This will create, every hour, a new ZFS snapshot tagged 'hour': # ls /.zfs/snapshot/ zbk-hour-20140318-140000 zbk-hour-20140318-150000 zbk-hour-20140318-160000 Only 24 of these snapshots will be kept (see Rotation below). The name of each snapshot comes with format `zbk-[tag]-[date]-[time]`. Date is `YYYYMMDD` and time is `hhmmss`. ## Snapshot groups Each snapshot is tagged: # create a snapshot tagged 'foobar'. Maintain 10 at all times zfssnap.sh foobar 10 Snapshots with the same tag make a **snapshot group**. For example, the `foobar` group will count up to 10 members at all times. Multiple groups can exist, just take snapshots with different tags: # take 2 'hourly' snaps zfssnap.sh hourly 10 zfssnap.sh hourly 10 # take 3 'daily' snaps zfssnap.sh daily 10 zfssnap.sh daily 10 zfssnap.sh daily 10 # ls /.zfs/snapshot zfs-hourly-20140318-140001 zfs-hourly-20140318-140003 zfs-daily-20140318-140111 zfs-daily-20140318-140112 zfs-daily-20140318-140114 Neither `zfssnap.sh` nor ZFS put a limit on the number of snaps you can maintain. The tool was tested with over 200. Bear in mind that it's shell scripts, so inherent limitations of arguments length could get in your way. I recommend staying under 50 snaps per group and 200 snaps total. ## Snapshot rotation `zfssnap.sh` takes a new snapshot every time it's run. When the number of existing snapshots exceeds the given limit, the oldest snapshot of that group (tag) is removed, so only so many are kept: # take snap xyz, then keep only last 2 from xyz group zfssnap.sh xyz 2 This bounds the number of snapshots for each group to 2. To remove all snaps in a group, simply pass ''i'' as limit: # remove all snaps of group xyz zfssnap.sh xyz 0 ## Excluding dataset from backup `zfssnap.sh` takes a recursive backup of the `zroot` pool. If you do not intend to maintain backups for certain datasets, you can exclude them with the `EXCLUDES` and `EXTRA_EXCLUDES` **environment variables**: # exclude only these datasets EXCLUDES=“/mydataset/foobar" # exclude these datasets in addition to default exclusions EXTRA_EXCLUDES=“/mydataset/foobar" Notice that these are **dataset names**, not mountpoints! If dataset `zroot/foo` is at mountpoint `/bar`, specify `/foo` here. The following datasets, common for FreeBSD users, are excluded by default: * `/usr/ports` * `/usr/src` * `/backups` If you do not want these excluded, pass an empty `EXCLUDES` envvar. # Recovering files (local backup) Lost a file? Find it under: # list content of michele's home at 2pm (1400) ls /.zfs/snapshot/zbk-hour-140000/home/michele Notice that you must look for the `/.zfs` directory at the root of the dataset actually holding it: # list content of michele's home, if /home is on zroot/home ls /home/.zfs/snapshot/zbk-hour-140000/michele # Full snapshot management cron example # take 15' backups for the last hour */15 * * * * root /usr/local/sbin/zfssnap.sh qrt 4 # take hourly backups for the 6 hours 1 * * * * root /usr/local/sbin/zfssnap.sh hourly 6 # take 6-hours backups for the last day 1 */6 * * * root /usr/local/sbin/zfssnap.sh 6hr 4 # take daily backups for the last week 1 1 * * * root /usr/local/sbin/zfssnap.sh day 7 # take weekly backups for the last 2 months 1 1 * * 1 root /usr/local/sbin/zfssnap.sh week 8 # Generating remote backups The `zfsbk.sh` lets you generate backups and upload them to a remote location. This takes a snapshot with tag `mybk` and serializes it in file `/backups/zbk-mybk-140000.dump`: # generate ZFS streaming package, save to /backups folder /usr/local/sbin/zfsbk.sh mybk ls /backups zfs-mybk-20140318-061900.dump # Incremental backups Pass a number to `zfsbk.sh` and it will create incremental snapshots: # 1. make full replication if this is the first snap in group # 2. else make incremental replication wrt latest snap in group # 3. reset the snap group after 1+9 steps have been made /usr/local/sbin/zfsbk.sh mybk 10 Incremental packages are named after their snapshot endpoints: ls /backups zbk-mybk-20140318-140000--zbk-mybk-20140318-150000.dump If the given integer is 1, `zfsbk.sh` sends full replication packages for every run. # Uploading backups remotely `zfsbk.sh` can upload each replication package after generating it, at the end of the run. Pass the destination coordinates with the `UPLOAD_PATH` environment variable. Currently, rsync:// and scp:// are supported: # take snap, generate backup, upload it to remote server UPLOAD_PATH="rsync://user@backup.server.com::server12/" /usr/local/sbin/zfsbk.sh mybk 10 `zfsbk.sh` relies on `zfssnap.sh` to take the snapshot to backup. Therefore, you can exclude different datasets from its backup by passing the respective `EXCLUDES` or `EXTRA_EXCLUDES` variables: # take selective backup EXTRA_EXCLUDES="/jails/test.dom.com" /usr/local/sbin/zfsbk.sh mybk 1