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Frequently Asked Questions
:Author: Liraz Siri <>
:Date: 2010-09-01
:Manual section: 7
:Manual group: backup
Is TKLBAM open source?
Yes, TKLBAM is licensed under the GPL3. You don't have to care about
free software ideology to appreciate the advantages. Any code running on
your server doing something as critical as encrypted backups should be
available for peer review and modification.
Where can I use TKLBAM?
On any system descended from a TurnKey Linux installation, regardless of
hardware or location. Storing backups to Amazon S3 is easiest because
authentication and key management are automatic. You just need to run::
But you can also backup to any storage target supported by TKLBAM's
back-end Duplicity including the local filesystem, NFS, Rsync, SSH, FTP,
WebDAV, Rackspace CloudFiles and even IMAP.
The local filesystem is one of the easier storage targets to use because
you don't need to mess around with authentication credentials.
So assuming you want to store your backup at /mnt/otherdisk::
tklbam-backup --address file:///mnt/otherdisk/tklbam/backup
tklbam-escrow /mnt/otherdisk/tklbam/key
And restore like this::
tklbam-restore --address file:///mnt/otherdisk/tklbam/backup \
Not as easy as the Hub-enabled "automatic" mode, but still vastly easier
than your conventional backup process. The disadvantage is that you
won't be able to restore/test your backup in the cloud, or from a VM
running in another office branch (for example). Also keep in mind that a
physical hard disk, even a RAID array, provides much much lower data
reliability compared with Amazon S3.
For this reason we recommend users use local backups to supplement cloud
backups (e.g., providing fast local access).
Why can't I backup a non-TurnKey Linux system with TKLBAM?
TKLBAM is short for 'TurnKey Linux' Backup and Migration. It's designed
specifically for TurnKey Linux and depends on many system-level details
that don't necessarily apply to other Linux distributions (e.g.,
installation method, versioning signatures, etc.).
In the future, we may figure out how to extend the design to support
additional operating systems, but it's not trivial and we don't have a
timeline on when, or even if, that will happen.
In the meantime, if you really want to use TKLBAM, consider
virtualization-based workarounds. For example, if you install a TurnKey
Linux VM on top of a Windows Server installation, you could use TKLBAM
to backup anything that goes into the TurnKey Linux VM.
Which TurnKey appliances are supported?
With a few exceptions, all TurnKey appliances images from the
2009.02 release batch onwards will work with TKLBAM, including the
recent Lucid and Lenny based Core betas.
Unfortunately, at this time Zimbra and the PostgreSQL based appliances
(PostgreSQL, LAPP, OpenBravo) are not yet supported.
PostgreSQL support is in the works but it's not ready yet.
Which databases are supported?
Currently only MySQL. PostgreSQL support is under development.
Support for additional databases will be added as needed. Currently
TurnKey appliances only include MySQL and PostgreSQL databases.
How much does this cost?
TKLBAM (and the TurnKey Hub) are currently free for private beta users.
Amazon S3 storage fees are around $0.15/GB per month. Full details of
Amazon S3 pricing can be found here.
You can use simulation mode to calculate how much uncompressed data
TKLBAM is going to store in a full backup::
$ tklbam-backup --simulate
In practice, the actual footprint of a full backup will usually be
smaller due to compression, but this depends on the type of data being
compressed (e.g., text compresses very well, video very poorly).
By default, a full backup is performed if one month has passed since the
last full backup. In between, incremental backups will be performed
which only record changes since the last backup. The full backup
frequency can be customized. See this manual page for details.
The Hub says my backup costs $0.00, what am I really paying?
If you notice $0.00 in the backups console, there's no need to open a
support request. It's not a bug. At 15 cents per gigabyte, if you have
just a few megabytes of data Amazon doesn't charge you anything.
Backups start from about 10KB for a freshly installed TurnKey appliance.
Remember, TKLBAM only saves changes you've made since the appliance was
In fact, a significant number of users are being charged less than 1
cent a month.
How does TKLBAM know what to backup on my system?
Every TurnKey appliance that TKLBAM supports has a corresponding
backup profile, which is downloaded from the Hub the first time you
backup an appliance. When required the profile can be updated on
demand (e.g., if we need to fix the profile)
The profile is stored in /var/lib/tklbam/profile and contains the
following text files:
1) dirindex.conf: a list of directories to check for changes by default.
This list does not include any files or directories maintained by the
package management system.
2) dirindex: appliance installation state - filesystem index
3) packages: appliance installation state - list of packages
Users can override which files and directories are checked for changes by
configuring overrides (See below).
How do I remove a file or directory from being included in my backup?
By adding a negative override to /etc/tklbam/overrides::
echo -/var/www/*/logs >> /etc/tklbam/overrides
How do I add a directory to my backup?
By adding an override to /etc/tklbam/overrides::
echo /mnt/images >> /etc/tklbam/overrides
Make sure you understand the implications of doing this. For example, if
you add a directory handled by package management this may break package
management on the system you restore to.
How do I exclude a database or table from my backup?
By adding a negative database override to /etc/tklbam/overrides::
# exclude drupal5 database
echo -mysql:drupal5 >> /etc/tklbam/overrides
# exclude sessions table in drupal6 database
echo -mysql:drupal6/sessions >> /etc/tklbam/overrides
By default ALL databases are backed up so adding a negative database
override override excludes only that database or table from the backup.
By contrast, a positive database override changes the default behavior
so that only the database or table specified in the override is included
in the backup.
You can mix positive overrides with negative overrides.
What's the difference between a full backup and an incremental backup?
A full backup is a backup that can be restored independently of any
other backup. An incremental backup links with the last backup before it
and only includes changes made since.
Backup chains are links of backup sessions which start with a full
backup, and then a series of incremental backups each recording only the
changes made since the backup before it. Incremental backups are useful
because they are fast and efficient.
Restoring an incremental backup requires retrieving the volumes of all
backup sessions made before it, up to and including the full backup that
started the chain. The longer the backup chain, the more time it will
take to restore.
How often does a does a full backup happen, how can I configure this?
By default, a full backup will happen if the last full backup is
older than 30 days. Between full backups, all backup sessions are
We recommend enabling the daily backup cron job so that daily
incremental backups happen automatically::
chmod +x /etc/cron.daily/tklbam-backup
You can override the default by setting the full-backup parameter in
the tklbam configuration::
# create a full backup every 14 days
echo full-backup 14D >> /etc/tklbam/conf
I forgot my passphrase, and I "lost" my escrow key. Can you help me?
Sorry, if your server is gone (e.g., terminated EC2 instance) nobody can
help you. Next time either save an escrow key somewhere[s] safe or don't
set a passphrase.
Don't misunderstand, we'd love to help if we could, but we can't. The
encryption key for your backup was generated locally on your server not
ours. We designed passphrase protection to use special cryptographic
countermeasures to make typical cracking techniques (e.g., dictionary
attacks) very difficult even for someone with access to massive amounts
of computer resources.
Note, if the system you backed up is still available, just log into it
as root and change the passphrase (you don't need to know the old
Do I have to use Amazon S3 for storage?
No. Any storage target supported by Duplicity can be forced by adding
the --address option when you backup and restore, but consider yourself
Here Be Dragons!
Doing this complicates usage as the Hub only helps you manage your
backups when it auto-configures the storage address. If you specify a
manual address you are on your own. You will need to manage backups,
encryption keys and authentication credentials by hand. You may also
run into unexpected bugs because this functionality has received limited
attention so far.
In short. Many things can go wrong so please be extra careful.
Why can't I access TKLBAM storage buckets with other Amazon S3 tools?
TKLBAM doesn't store it's data in generic S3 buckets, but in an isolated
TKLBAM-specific area on S3. This means generic S3 tools such as the AWS
management console, or S3Fox will not be able to access the storage
buckets in which TKLBAM backup volumes reside.
What are the advantages of isolating TKLBAM Amazon S3 storage?
1) Easier sign up process. Users don't need to know anything about S3
API keys or understand the implications of giving them to us.
2) Security: you don't need to give us access to your generic S3
account. If someone compromises your regular AWS API Key they still
can't get to your encrypted backup volumes and say... delete them.
3) Cost transparency: TKLBAM related storage charges show up separately
from your generic S3 storage.
What happens if my payment method to Amazon is invalidated?
Amazon supports payment by credit card and bank account. We recommend
heavy users add a bank account as their payment method, as it's usually
more permanent than a credit card.
In any case, if your payment method is invalidated (e.g., cancelled or
expired credit card), billing will fail and Amazon will attempt to
contact you (e.g., by e-mail) to provide a new, valid payment method.
Is the Hub TKLBAM's central point of failure?
Yes and no. On one hand, much of the streamlined usability of TKLBAM
depends on the availability of the Hub. On the other hand, we designed
TKLBAM to degrade gracefully if the Hub ever goes down (it shouldn't!).
As we scale the Hub we will gradually add capacity and build in
additional layers of fault tolerance.
We have monitoring in place which alerts us immediately if anything
unexpected happens.
If the Hub goes down, will my backup cron jobs still work?
Yes. Backups which have already been configured will continue to work
normally. If TKLBAM can't reach the Hub it just uses the locally cached
profile and S3 address.
If my connection to the Hub goes down, can I still restore?
Yes - manually. It just won't be as easy. You'll need to do a couple of
steps by hand:
1) transfer the escrow key to the restore target.
This means you'll need to have stored the escrow key somewhere safe
or be able to create it on the backed up machine.
2) specify the S3 address and the key manually when you restore.
For more details see the tklbam-restore documentation.
If the Hub goes down, can I still create a new backup?
Yes - but only manually. Just remember the Hub won't know anything about
these backups so you'll have manage keys and authentication credentials
by hand.
``tklbam`` (8)
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