| 1 | <?xml version="1.0" encoding="UTF-8"?>
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| 2 | <!DOCTYPE topic
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| 3 | PUBLIC "-//OASIS//DTD DITA Topic//EN" "topic.dtd">
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| 4 | <topic xml:lang="en-us" id="snapshots-take-restore-delete">
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| 5 | <title>Taking, Restoring, and Deleting Snapshots</title>
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| 6 |
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| 7 | <body>
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| 8 | <p>
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| 9 | There are three operations related to snapshots, as follows:
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| 10 | </p>
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| 11 | <ol>
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| 12 | <li>
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| 13 | <p>
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| 14 | <b outputclass="bold">Take a snapshot.</b> This makes
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| 15 | a copy of the machine's current state, to which you can go
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| 16 | back at any given time later.
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| 17 | </p>
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| 18 | <ul>
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| 19 | <li>
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| 20 | <p>
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| 21 | If your VM is running:
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| 22 | </p>
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| 23 | <p>
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| 24 | Select <b outputclass="bold">Take Snapshot</b>
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| 25 | from the <b outputclass="bold">Machine</b> menu
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| 26 | in the VM window.
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| 27 | </p>
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| 28 | <p>
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| 29 | The VM is paused while the snapshot is being created.
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| 30 | After snapshot creation, the VM continues to run as
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| 31 | normal.
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| 32 | </p>
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| 33 | </li>
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| 34 | <li>
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| 35 | <p>
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| 36 | If your VM is in either the Saved or the Powered Off
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| 37 | state, as displayed next to the VM name in the machine
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| 38 | list:
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| 39 | </p>
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| 40 | <p>
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| 41 | Display the Snapshots window and do one of the
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| 42 | following:
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| 43 | </p>
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| 44 | <ul>
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| 45 | <li>
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| 46 | <p>
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| 47 | Click <b outputclass="bold">Take</b> in the
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| 48 | Snapshots window toolbar.
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| 49 | </p>
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| 50 | </li>
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| 51 | <li>
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| 52 | <p>
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| 53 | Right-click on the <b outputclass="bold">Current
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| 54 | State </b>item in the list and select
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| 55 | <b outputclass="bold">Take</b>.
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| 56 | </p>
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| 57 | </li>
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| 58 | </ul>
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| 59 | </li>
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| 60 | </ul>
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| 61 | <p>
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| 62 | A dialog is displayed, prompting you for a snapshot name.
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| 63 | This name is purely for reference purposes, to help you
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| 64 | remember the state of the snapshot. For example, a useful
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| 65 | name would be "Fresh installation from scratch, no Guest
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| 66 | Additions", or "Service Pack 3 just installed". You can also
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| 67 | add a longer text description in the
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| 68 | <b outputclass="bold">Snapshot Description</b> field.
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| 69 | </p>
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| 70 | <p>
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| 71 | Your new snapshot will then appear in the snapshots list.
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| 72 | Underneath your new snapshot, you will see an item called
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| 73 | <b outputclass="bold">Current State</b>, signifying
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| 74 | that the current state of your VM is a variation based on
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| 75 | the snapshot you took earlier. If you later take another
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| 76 | snapshot, you will see that they are displayed in sequence,
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| 77 | and that each subsequent snapshot is derived from an earlier
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| 78 | one.
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| 79 | </p>
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| 80 | <fig id="fig-snapshots-list">
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| 81 | <title>Snapshots List For a Virtual Machine</title>
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| 82 | <image href="images/snapshots-2.png" placement="break"/>
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| 83 | </fig>
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| 84 | <p>
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| 85 | Oracle VM VirtualBox imposes no limits on the number of snapshots
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| 86 | you can take. The only practical limitation is disk space on
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| 87 | your host. Each snapshot stores the state of the virtual
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| 88 | machine and thus occupies some disk space. See
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| 89 | <xref href="snapshots-contents.dita#snapshots-contents"/> for details on what is
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| 90 | stored in a snapshot.
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| 91 | </p>
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| 92 | </li>
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| 93 | <li>
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| 94 | <p>
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| 95 | <b outputclass="bold">Restore a snapshot.</b> In the
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| 96 | Snapshots window, select the snapshot you have taken and
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| 97 | click <b outputclass="bold">Restore</b> in the
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| 98 | toolbar. By restoring a snapshot, you go back or forward in
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| 99 | time. The current state of the machine is lost, and the
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| 100 | machine is restored to the exact state it was in when the
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| 101 | snapshot was taken.
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| 102 | </p>
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| 103 | <note>
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| 104 | <p>
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| 105 | Restoring a snapshot will affect the virtual hard drives
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| 106 | that are connected to your VM, as the entire state of the
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| 107 | virtual hard drive will be reverted as well. This means
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| 108 | also that all files that have been created since the
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| 109 | snapshot and all other file changes <i>will be
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| 110 | lost. </i>In order to prevent such data loss while
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| 111 | still making use of the snapshot feature, it is possible
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| 112 | to add a second hard drive in
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| 113 | <i>write-through</i> mode using the
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| 114 | <userinput>VBoxManage</userinput> interface and use it to
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| 115 | store your data. As write-through hard drives are
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| 116 | <i>not</i> included in snapshots, they
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| 117 | remain unaltered when a machine is reverted. See
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| 118 | <xref href="hdimagewrites.dita#hdimagewrites"/>.
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| 119 | </p>
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| 120 | </note>
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| 121 | <p>
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| 122 | To avoid losing the current state when restoring a snapshot,
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| 123 | you can create a new snapshot before the restore operation.
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| 124 | </p>
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| 125 | <p>
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| 126 | By restoring an earlier snapshot and taking more snapshots
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| 127 | from there, it is even possible to create a kind of
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| 128 | alternate reality and to switch between these different
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| 129 | histories of the virtual machine. This can result in a whole
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| 130 | tree of virtual machine snapshots.
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| 131 | </p>
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| 132 | </li>
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| 133 | <li>
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| 134 | <p>
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| 135 | <b outputclass="bold">Delete a snapshot.</b> This
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| 136 | does not affect the state of the virtual machine, but only
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| 137 | releases the files on disk that Oracle VM VirtualBox used to store
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| 138 | the snapshot data, thus freeing disk space. To delete a
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| 139 | snapshot, select the snapshot name in the Snapshots window
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| 140 | and click <b outputclass="bold">Delete</b> in the
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| 141 | toolbar. Snapshots can be deleted even while a machine is
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| 142 | running.
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| 143 | </p>
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| 144 | <note>
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| 145 | <p>
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| 146 | Whereas taking and restoring snapshots are fairly quick
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| 147 | operations, deleting a snapshot can take a considerable
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| 148 | amount of time since large amounts of data may need to be
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| 149 | copied between several disk image files. Temporary disk
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| 150 | files may also need large amounts of disk space while the
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| 151 | operation is in progress.
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| 152 | </p>
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| 153 | </note>
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| 154 | <p>
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| 155 | There are some situations which cannot be handled while a VM
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| 156 | is running, and you will get an appropriate message that you
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| 157 | need to perform this snapshot deletion when the VM is shut
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| 158 | down.
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| 159 | </p>
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| 160 | </li>
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| 161 | </ol>
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| 162 | </body>
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| 163 |
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| 164 | </topic>
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