Difference between revisions of "Ploop/Backup"

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[[File:Ploop-backup.png|300px|right|thumb|How backup via snapshot is done]]
 
[[File:Ploop-backup.png|300px|right|thumb|How backup via snapshot is done]]
−
This article explains how to do consistent file-based backups for [[ploop]] containers, using ploop snapshot feature.
+
This article explains how to do consistent backups for [[ploop]] containers, using ploop snapshot feature.
 +
 
 +
== Backup types ==
 +
There are two ways of doing backups, both have their pros and cons.
 +
 
 +
* When doing an '''image backup''', one copies ploop image files directly. There can be only one big file, or maybe a few relatively big files. Copying a few big files (rather than a lot of small files) is faster because there's not too much metadata (file info) to be copied). Also, filesystem properties are fully preserving (since images containing the filesystem are copied).
 +
 
 +
* When doing a '''file backup''', one copies individual container' files. This is more suitable if you want selective backups (such as only some directories/files).
 +
 
 +
The following table summarizes pros and cons of both approaches.
 +
 
 +
{| class="wikitable"
 +
! Characteristic
 +
! Image
 +
! File
 +
|-
 +
|| Incremental backups
 +
| {{Yes}} || {{Yes-No}}{{H:title|Requires tools such as rsnapshot|<sup>*</sup>}}
 +
|-
 +
|| Selective backups
 +
| {{No}} || {{Yes}}
 +
|-
 +
|| Faster full backup and restore
 +
| {{Yes}} || {{No}}
 +
|-
 +
| Preserve filesystem properties
 +
| {{Yes}} || {{No}}
 +
|-
 +
|| Compatible with pre-ploop backups
 +
| {{Yes-No}}{{H:title|It's always possible to create a new, same-size ploop device and then restore the files into the mounted ploop partition|<sup>*</sup>}} || {{Yes}}
 +
|-
 +
|| Restore individual files
 +
| {{Yes}} || {{Yes}}
 +
|}
 +
 
 +
== Image-based backup ==
 +
 
 +
Assuming you have a running container identified by <code>$CTID</code>. The following needs to be done:
 +
 
 +
<source lang="bash">
 +
# Known snapshot ID
 +
ID=$(uuidgen)
 +
VE_PRIVATE=$(vzlist -H -o private $CTID)
 +
 
 +
# Take a snapshot without suspending a CT and saving its config
 +
vzctl snapshot $CTID --id $ID --skip-suspend --skip-config
 +
 
 +
# Perform a backup using your favorite backup tool
 +
# (cp is just an example)
 +
cp $VE_PRIVATE/root.hdd/* /backup/destination
 +
 
 +
# Delete (merge) the snapshot
 +
vzctl snapshot-delete $CTID --id $ID
 +
</source>
 +
 
 +
The following script implements the commands above and allows - when stored as <code>vzbackup</code> - to backup your container by executing the script in the following way:
 +
 
 +
<code>./vzbackup 101 /backup/destination/</code>
 +
 
 +
The script removes older backups and keeps only the latest four backups. You can change the number of backups kept by changing the four in <code>head -n-4</code> to the number of backups you would like to keep.
 +
 
 +
<source lang="bash">
 +
#!/bin/bash
 +
if [ -z $1 -o -z $2 ]
 +
then
 +
echo "Usage: vzbackup CTID BACKUP-PATH"
 +
exit 1
 +
fi
 +
 
 +
CTID=$1
 +
FOLDER=$2
 +
BACKUPPATH=$FOLDER/$CTID-$( date +%F_%H_%M )
 +
 
 +
#create BACKUP-PATH
 +
mkdir -p $BACKUPPATH
 +
 
 +
# Known snapshot ID
 +
ID=$(uuidgen)
 +
VE_PRIVATE=$(vzlist -H -o private $CTID)
 +
 +
# Take a snapshot without suspending a CT and saving its config
 +
vzctl snapshot $CTID --id $ID --skip-suspend --skip-config
 +
 +
# Perform a backup using your favorite backup tool
 +
# (cp is just an example)
 +
cp $VE_PRIVATE/root.hdd/* $BACKUPPATH/
 +
 +
# Delete (merge) the snapshot
 +
vzctl snapshot-delete $CTID --id $ID
 +
 
 +
# remove old backups
 +
rm -rf $( find $FOLDER -type d -name "$CTID*" -exec ls -d1rt "{}" + | head -n-4  )
 +
 
 +
echo "BACKUP FINISHED."
 +
</source>
 +
 
 +
== File-based backup ==
  
 
Assuming you have a running container identified by <code>$CTID</code>. The following needs to be done:
 
Assuming you have a running container identified by <code>$CTID</code>. The following needs to be done:
Line 20: Line 116:
 
# Perform a backup using your favorite backup tool
 
# Perform a backup using your favorite backup tool
 
# (tar is just an example)
 
# (tar is just an example)
−
tar cf backup.tar.xz $MNTDIR
+
tar cf backup.tar $MNTDIR
 +
 
 +
# tar with compression examples, see man page of tar for more options
 +
# tar cfJ backup.tar.xz $MNTDIR
 +
# tar cfz backup.tar.gz $MNTDIR
  
 
# Unmount the snapshot
 
# Unmount the snapshot
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</source>
 
</source>
  
−
For more information, see [[Man/vzctl.8#Snapshotting|vzctl(8), section Snapshotting]].
+
== See also ==
 +
 
 +
* [[Ploop]]
 +
* [[Man/vzctl.8#Snapshotting|vzctl(8), section Snapshotting]].
  
−
[[Category:ploop]]
+
[[Category: Storage]]
−
[[Category:HOWTO]]
+
[[Category: HOWTO]]

Latest revision as of 16:46, 6 September 2015

How backup via snapshot is done

This article explains how to do consistent backups for ploop containers, using ploop snapshot feature.

Backup types[edit]

There are two ways of doing backups, both have their pros and cons.

  • When doing an image backup, one copies ploop image files directly. There can be only one big file, or maybe a few relatively big files. Copying a few big files (rather than a lot of small files) is faster because there's not too much metadata (file info) to be copied). Also, filesystem properties are fully preserving (since images containing the filesystem are copied).
  • When doing a file backup, one copies individual container' files. This is more suitable if you want selective backups (such as only some directories/files).

The following table summarizes pros and cons of both approaches.

Characteristic Image File
Incremental backups Yes Yes/No*
Selective backups No Yes
Faster full backup and restore Yes No
Preserve filesystem properties Yes No
Compatible with pre-ploop backups Yes/No* Yes
Restore individual files Yes Yes

Image-based backup[edit]

Assuming you have a running container identified by $CTID. The following needs to be done: 

# Known snapshot ID
ID=$(uuidgen)
VE_PRIVATE=$(vzlist -H -o private $CTID)

# Take a snapshot without suspending a CT and saving its config
vzctl snapshot $CTID --id $ID --skip-suspend --skip-config

# Perform a backup using your favorite backup tool
# (cp is just an example)
cp $VE_PRIVATE/root.hdd/* /backup/destination

# Delete (merge) the snapshot
vzctl snapshot-delete $CTID --id $ID

The following script implements the commands above and allows - when stored as vzbackup - to backup your container by executing the script in the following way:

./vzbackup 101 /backup/destination/

The script removes older backups and keeps only the latest four backups. You can change the number of backups kept by changing the four in head -n-4 to the number of backups you would like to keep. 

#!/bin/bash
if [ -z $1 -o -z $2 ]
then
	echo "Usage: vzbackup CTID BACKUP-PATH"
	exit 1
fi

CTID=$1
FOLDER=$2
BACKUPPATH=$FOLDER/$CTID-$( date +%F_%H_%M )

#create BACKUP-PATH
mkdir -p $BACKUPPATH

# Known snapshot ID
ID=$(uuidgen)
VE_PRIVATE=$(vzlist -H -o private $CTID)
 
# Take a snapshot without suspending a CT and saving its config
vzctl snapshot $CTID --id $ID --skip-suspend --skip-config
 
# Perform a backup using your favorite backup tool
# (cp is just an example)
cp $VE_PRIVATE/root.hdd/* $BACKUPPATH/
 
# Delete (merge) the snapshot
vzctl snapshot-delete $CTID --id $ID

# remove old backups
rm -rf $( find $FOLDER -type d -name "$CTID*" -exec ls -d1rt "{}" + | head -n-4  )

echo "BACKUP FINISHED."

File-based backup[edit]

Assuming you have a running container identified by $CTID. The following needs to be done: 

# Known snapshot ID
ID=$(uuidgen)

# Directory used to mount a snapshot
MNTDIR=./mnt
mkdir $MNTDIR

# Take a snapshot without suspending a CT and saving its config
vzctl snapshot $CTID --id $ID --skip-suspend --skip-config

# Mount the snapshot taken
vzctl snapshot-mount $CTID --id $ID --target $MNTDIR

# Perform a backup using your favorite backup tool
# (tar is just an example)
tar cf backup.tar $MNTDIR

# tar with compression examples, see man page of tar for more options
# tar cfJ backup.tar.xz $MNTDIR
# tar cfz backup.tar.gz $MNTDIR

# Unmount the snapshot
vzctl snapshot-umount $CTID --id $ID

# Delete (merge) the snapshot
vzctl snapshot-delete $CTID --id $ID

See also[edit]

Retrieved from "https://wiki.openvz.org/index.php?title=Ploop/Backup&oldid=17557"