Difference between revisions of "Life Preserver/9.2/en"

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* in order to boot from the disk should the primary disk fail, the system must support booting from the new disk. For example, if you are using a USB disk, make sure that the BIOS is able to boot from a USB disk.
* in order to boot from the disk should the primary disk fail, the system must support booting from the new disk. For example, if you are using a USB disk, make sure that the BIOS is able to boot from a USB disk.
Once these requirements are met, you can setup the new disk in this method:
The superuser can setup the new disk using the following command. Replace ''tank1'' with the name of your ZFS pool and ''/dev/da0'' with the name of the disk to format. For example, the first USB disk will be ''/dev/da0'' and the second internal hard disk will be ''/dev/ad1''.
  # lpreserver zpool attach <zpoolname> <new disk>
  # lpreserver zpool attach <zpoolname> <new disk>

Revision as of 10:32, 12 September 2013

(Sorry for the inconvenience)


The built-in Life Preserver utility was redesigned for 9.2 to take full advantage of ZFS snapshot functionality. This utility now allows you to schedule snapshots of a ZFS pool and to securely replicate those snapshots to another system using SSH. This design provides several benefits:

  • a snapshot provides a "point-in-time" image of the ZFS pool. In one way, this is similar to a full system backup as the snapshot contains the information for the entire filesystem. However, it has several advantages over a full backup. Snapshots occur instantaneously, meaning that the filesystem does not need to be unmounted and you can continue to use applications on your system as the snapshot is created. Since snapshots contain the meta-data ZFS uses to access files, the snapshots themselves are small and subsequent snapshots only contain the changes that occurred since the last snapshot was taken. This space efficiency means that you can take snapshots often. Snapshots also provide a convenient way to access previous versions of files as you can simply browse to the point-in-time for the version of the file that you need. Life Preserver makes it easy to configure when snapshots are taken and provides a built-in graphical browser for finding and restoring the files within a snapshot.
  • replication is an efficient way to keep the files on two systems in sync. In the case of Life Preserver, the snapshots taken on the PC-BSD system will be synchronized with their versions stored on the backup server.
  • SSH means that the snapshots will be sent to the backup server oven an encrypted connection, which protects the contents of the snapshots.

When choosing which system to use as the backup server, keep the following points in mind:

  • the backup server must be formatted with the latest version of ZFS, also known as ZFS feature flags or ZFSv5000. Operating systems that support this version of ZFS include PC-BSD 9.2, FreeBSD 9.2, and FreeNAS 9.1.x.
  • that system must have SSH installed and the SSH service must be running. If the backup server is running PC-BSD, you can start SSH using Service Manager. If that system is running FreeNAS, SSH is already installed. How to configure this service is described in Backing Up to a FreeNAS System. If the system is running FreeBSD, SSH is already installed.
  • if the backup server is running PC-BSD, you will need to open TCP ports 22 (SSH) using Firewall Manager. If the server is running FreeBSD and a firewall has been configured, add rules to open this port in the firewall ruleset. FreeNAS does not run a firewall by default.
Figure 8.19a: Life Preserver Icon in System Tray


Managing Snapshots Using the GUI

An icon to the Life Preserver utility, seen in Figure 8.19a, can be found in the system tray.

To remove the icon from the system tray, right-click it. To re-add it to the tray, go to Control Panel ➜ Life Preserver or type pc-su life-preserver & at the command line. If your desktop manager does not provide a system tray, you will need to instead manage backups from the command line.

To open the screen shown in Figure 8.19b, double-click the Life Preserver icon. Click the "+" button and select the name of the ZFS pool to backup. Unless you configured a custom pool name during installation, it will be tank. This will launch the the "New Life Preserver Wizard", allowing you to configure the backup schedule. Click "Next" to see the screen in Figure 8.19c.

Figure 8.19b: Life Preserver Screen
Figure 8.19c: Snapshot Schedule Screen

This screen is used to schedule how often a snapshot is taken of the system. The default is to perform one snapshot per day at 1:00 AM. You can either change the time that this one daily snapshot occurs or select to take a snapshot once every hour, 30 minutes, 10 minutes or 5 minutes.

After making your selection, press "Next" to see the screen shown in Figure 8.19d.

Figure 8.19d: Snapshot Pruning Screen

This screen schedules how long to keep the created snapshots. By default, the last 7 days of snapshots are stored on the backup server. In other words, once a snapshot becomes older than 7 days, it is deleted on the backup server. You can select to either keep snapshots for so many days or to keep a certain quantity of snapshots.

After making your selection, press "Next" to see the screen shown in Figure 8.19e.

Figure 8.19e: Replication Server Screen

This screen is used to indicate which system to send the backups to. Click the "Replicate my data" box, then input the following information:

  • Host Name: of the remote system that will store your backup. If the backup server is on your local network, the host name must be in your hosts file or in the database of the local DNS server. You may find it easier to instead input the IP address of the backup server as this will eliminate any host name resolution problems.
  • User Name: this user must have permission to log in to the system that will hold the backup. If the account does not already exist, you should create it first on the backup server.
  • SSH Port: port 22, the default port used by SSH is selected for you. You only need to change this if the remote system is using a non-standard port to listen for SSH connections. In that case, use the up/down arrows or type in the port number.
  • Remote Dataset: input the name of an existing ZFS dataset on the backup server. This is where the backups will be stored. To get a list of existing datasets, type zfs list on the remote server. The "NAME" column in the output of that command gives the fullname of each dataset. Type the fullname of the desired dataset into this field. When selecting a dataset, make sure that the selected "User Name" has permission to write to the dataset.

Once you have input the information, click "Next" and then "Finish". Life Preserver will check that it can connect to the backup server. A pop-up message will remind you to save the SSH key to a USB stick (as described below) as this key is required should you ever need to perform an operating system restore. It will then add an entry for the backup in the screen shown in Figure 8.19b.

You should also create a test snapshot (also described below) to ensure that Life Preserver can successfully replicate to the backup server. The first time you create a test snapshot, you should receive a "OpenSSH Authentication Passphrase Request" pop-up message. Once you click OK, it will prompt for the password of "User Name". Input that user's password to start replication of that snapshot.

NOTE: If you don't receive the pop-up message, check that the firewall on the backup system, or a firewall within the network, is not preventing access to the configured "SSH Port".

Configuration Options

Click the entry for a backup to activate its configuration buttons, as shown in Figure 8.19f.

Figure 8.19f: Life Preserver Entry

These buttons, from left to right, allow you to:

  • Enable backups of a new dataset: this button will be greyed out if you only have one pool and have already scheduled a backup of the pool. Otherwise, it will start the "New Life Preserver Wizard" as described above.
  • Remove selected dataset from automatic backup: if you click this button, a pop-up message will ask if you wish to cancel snapshot creation and replication. If you click "Yes", another pop-up message will ask if you also want to permanently delete all of the snapshots currently stored on the local PC-BSD system.
  • Customize the backup configuration: this will open the screen shown in Figure 8.19g so that you can modify when the backups occur and how long they are stored on the backup server. If you click the "Replication" tab, you will see the screen shown in Figure 8.19h. This allows you to edit the connection information to the backup server. It also adds a "Frequency" option. By default, the backup occurs right after the snapshot is created. You can modify this so that the backup itself occurs at a set time, regardless of when the snapshots are created. For example, if you have configured snapshots to occur every 30 minutes but the replication frequency to occur daily at 2:00 AM, the newly created snapshots won't be copied to the backup server until 2:00 AM.
  • Manage SSH keys: after creating a backup entry, you should immediately generate an SSH key and copy it to a USB stick. To do so, click this button then click "Generate SSH Key". A pop-up message will indicate that the key was successfully generated. Then, insert a FAT32 formatted USB stick and mount it with Mount Tray. Then, click this button again and select "Copy To USB Stick".
  • Make a new snapshot: click this button to create a backup now, instead of waiting for the schedule. You should create a test snapshot to make sure that replication occurs successfully. You can also create a snapshot before making changes to a file, so that you can preserve a copy of the previous version of the file. When creating a snapshot, a pop-up message will prompt you to input a name for the snapshot. Once you do, the "Latest Snapshot" field will show the name of the snapshot (with the date and time added). The snapshot itself happens instantaneously, however the replication of the snapshot to the backup server will take some time, depending upon the speed of the network and the size of the snapshot. The Life Preserver icon will change to indicate whenever a replication is in progress.
  • Browse a snapshot: click this button to browse to the data stored in a snapshot. In the example shown in Figure 8.19i, two test snapshots have been taken: the first was taken on September 10 at 11:02 and the second was taken on September 10 at 11:09. The datasets contained within the ZFS pool are listed and if you hover over a dataset name, such as /usr/home/dru, the available snapshots are listed. If you click a snapshot name, the contents of that dataset at that point in time will be displayed in the "Revert a file" screen. For example, if a file named /usr/home/dru/important.odt was modified at 11:05 and the user wished to access the previous version of that file, they could browse to it in the test-2013-09-10-11-02-23 snapshot as that snapshot was taken before the file was modified. If you double-click a file, it will restore that file to the version it was at the time the snapshot was taken.
  • Revert an entire data subset: use this option with care as it will restore every single file in the selected dataset to the point-in-time when the snapshot was taken. While this can sometimes be handy if you mess things up in a dataset, it will also overwrite all of the files that were modified since that point-in-time.
Figure 8.19g: Changing the Backup Schedule
Figure 8.19h: Changing the Replication Schedule
Figure 8.19i: Browsing Snapshots

Managing Snapshots From the Command Line

The lpreserver command line utility can be used to manage snapshots and replication from the command line of a PC-BSD® or TrueOS® system. This command needs to be run as the superuser. To display its usage, type the command without any arguments:


Available commands

  cronsnap - Schedule snapshot creation via cron
       get - Get list of lpreserver options
  listcron - Listing of scheduled snapshots
  listsnap - List snapshots of a zpool/dataset
    mksnap - Create a ZFS snapshot of a zpool/dataset
 replicate - Enable / Disable ZFS replication to a remote system
revertsnap - Revert zpool/dataset to a snapshot
    rmsnap - Remove a snapshot
       set - Set lpreserver options
    status - List datasets, along with last snapshot / replication date 
     zpool - Manage a zpool by attaching / detaching disks

Each command has its own help text that describes its parameters and provides a usage example. For example, to receive help on how to use the lpreserver cronsnap command, type:

lpreserver help cronsnap
Help cronsnap
Schedule a ZFS snapshot
For a listing of all scheduled snapshots
 # lpreserver listcron
 To start / stop snapshot scheduling
 # lpreserver cronsnap <dataset> <action> <frequency> <numToKeep>
 action = start / stop
 frequency = daily@XX / hourly / 30min / 10min / 5min
                   ^^ Hour to execute
 numToKeep = Number of snapshots to keep total
 lpreserver cronsnap tank1/usr/home/kris start daily@22 10
 lpreserver cronsnap tank1/usr/home/kris stop

Table 8.19a shows the command line equivalents to the graphical options provided by the Life Preserver GUI. Note that some options are only available from the command line.

Table 8.19a: Command Line and GUI Equivalents

Command Line GUI Description
cronsnap Customize the backup configuration ➜ Local Snapshots schedule when snapshots occur and how long to keep them; the "stop" option can be used to disable snapshot creation
get list Life Preserver options
listcron main screen of Life Preserver list which ZFS pools have a scheduled snapshot
listsnap Browse a snapshot list snapshots of specified dataset
mksnap Make a new snapshot create and replicate a new ZFS snapshot; by default, snapshots are recursive, meaning that a snapshot is taken of every dataset within a pool
replicate Customize the backup configuration ➜ Replication used to list, add, and remove backup server; read the help for this command for examples
revertsnap Revert an entire data subset revert dataset to the specified snapshot version
rmsnap Remove selected dataset from automatic backup deletes specified snapshot; by default, all datasets within the snapshot are deleted
set configures Life Preserver options; read help for the list of configurable options
status main screen of Life Preserver lists the last snapshot name and replication status
zpool used to attach/detach drives from the pool; read help for examples

Mirroring the System to a Local Disk

In addition to replicating to a remote server, the lpreserver command also provides a method for attaching a new disk drive to an existing ZFS pool, and live-mirroring all data to that disk as data changes on the pool. The attached disk drive can be another internal disk or an external USB disk. When the new disk is attached for the first time, it will be erased and used solely as a mirror of the existing system drive. In addition, it will be made bootable, allowing you to boot from and use the new disk should the primary disk fail. In order to use this feature you will need the following:

  • an internal or external disk drive that is the same size or larger than the existing system disk.
  • since the disk will be formatted, it must be either blank or not have any data that you wish to keep intact.
  • in order to boot from the disk should the primary disk fail, the system must support booting from the new disk. For example, if you are using a USB disk, make sure that the BIOS is able to boot from a USB disk.

The superuser can setup the new disk using the following command. Replace tank1 with the name of your ZFS pool and /dev/da0 with the name of the disk to format. For example, the first USB disk will be /dev/da0 and the second internal hard disk will be /dev/ad1.

# lpreserver zpool attach <zpoolname> <new disk>

When the disk is first attached, it will be re-formatted and setup to "mirror" your existing disk. Note that if you can add multiple disks to your zpool in this manner, giving you any level of redundancy that you require.

Once the disk is attached, it will then be put into a "resilvering" state, where the data from your primary disk is being copied to the newly attached disk. This may take a while depending upon the speed of the disks and system load. Until this is finished you should not reboot the system, or detach the disk.

To get a listing of the disks in your mirror you can run the command:

# lpreserver zpool list <zpoolname>

If you are using an external drive there may be occasions where you wish to disconnect the backup drive, such as when using a laptop and going on the road. In order to so this safely, it is recommended that you first mark the external disk as "offline" using the following command:

# lpreserver zpool offline <zpoolname> <disk>

Then when you re-connect the drive you can place it in online mode again using:

# lpreserver zpool online <zpoolname> <disk>
(Note that sometimes the disk name will change as a result of being disconnected, use lpreserver zpool list <zpoolname> to get the proper device ID)

Sometimes, the disk name will change as a result of being disconnected. The lpreserver zpool list tank1 command can be used to get the proper device ID.

If you wish to remove a disk from this mirror array permanently you can do so with the following command. (Note that if you wish to re-attach this disk later, a FULL disk copy will again have to be performed)

# lpreserver zpool detach <zpoolname> <disk>

NOTES: In addition to working with mirrors, this method can also be used to manage a raidz setup zpool, although you will probably not want to use external disks in this case.

Backing Up to a FreeNAS System

FreeNAS®[1] is an open source Networked Attached Storage (NAS) operating system based on FreeBSD. This operating system is designed to be installed onto a USB stick or CF card so that it is kept separate from the storage disk(s) installed on the system. You can download the latest version of FreeNAS® as well as a PDF of its Users Guide from the download page of the FreeNAS® website.

This section demonstrates how to configure FreeNAS® 9.1.1 as the backup server for Life Preserver to replicate to. It assumes that you have already installed this version of FreeNAS® using the installation instructions in the FreeNAS® 9.1.1 Users Guide and are able to access the FreeNAS® system from a web browser.

In order to prepare the FreeNAS® system to store the backups created by Life Preserver, you will need to create a ZFS volume, create and configure the dataset to store the backups, create a user account that has permission to access that dataset, and enable the SSH service.

In the example shown in Figure 8.19j, the system has three 40GB drives and the user has clicked Storage ➜ Volumes ➜ ZFS Volume Manager in order to create the ZFS volume.

Figure 8.19j: Creating a ZFS Volume in FreeNAS® 9.1.1


Input a "Volume Name", drag the slider to select the number of disks, and click the "Add Volume" button. The ZFS Volume Manager will automatically select the optimal layout for both storage capacity and redundancy. In this example, a RAIDZ1 volume named volume1 will be created.

To create the dataset to backup to, click the + next to the entry for the newly created volume, then click Create ZFS Dataset. In the example shown in Figure 8.19k, the "Dataset Name" is backups. Click the "Add Dataset" button to create the dataset.

Figure 8.19k: Creating a ZFS Dataset in FreeNAS® 9.1.1


To create the user account, go to Account ➜ Users ➜ Add User. In the screen shown in Figure 8.19l, input a "Username" that will match the "User Name" configured in Life Preserver. Under "Home Directory", use the browse button to browse to the location that you made to store the backups. Input a "Full Name", then input and confirm a "Password". When finished, click the "OK" button to create the user.

Figure 8.19l: Creating a User in FreeNAS® 9.1.1


Next, click on Shell and type the following command, replacing dru and volume1/backups with the name of the user, volume, and dataset that you created:

zfs allow -u dru create,receive,mount,userprop,destroy,send,hold volume1/backups

Finally, to enable the SSH service, go to Services ➜ Control Services, shown in Figure 8.19m.

Figure 8.19m: Enabling Services in FreeNAS® 9.1.1


Click the red "OFF" button next to SSH to enable that service. Once it turns to a blue "ON", the FreeNAS® system is ready to be used as the backup server.

When configuring Life Preserver, use the IP address of the FreeNAS® system in the "Host Name" field, the name of the user you created in the "User Name" field, and the name of the dataset you created, in this example it is volume1/backups, in the "Remote Dataset" field.

Restoring the Operating System From a Replicated Life Preserver Backup


Troubleshooting Replication


  1. http://www.freenas.org
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