## ccollect - Installing, Configuring and Using

### Nico Schottelius

`<nico-ccollect__@__schottelius.org>`

Revision History
Revision 2.10 | for ccollect 2.10, Initial Version from 2006-01-13 | NS

(pseudo) incremental backup with different exclude lists using hardlinks and `rsync`

## Introduction

`ccollect` is a backup utility written in the sh-scripting language. It does not depend on a specific shell, only `/bin/sh` needs to be bourne shell compatible (like dash, ksh, zsh, bash, …).

### Supported and tested operating systems and architectures

`ccollect` was successfully tested on the following platforms:

- FreeBSD on amd64/i386
- GNU/Linux on amd64/arm/hppa/i386/ppc
- Mac OS X 10.5
- NetBSD on alpha/amd64/i386/sparc/sparc64
- OpenBSD on amd64
- Windows by installing Cygwin, OpenSSH and rsync

It should run on any Unix that supports `rsync` and has a POSIX-compatible bourne shell. If your platform is not listed above and you have it successfully running, please drop me a mail.

### Why you COULD only backup from remote hosts, not to them

While considering the design of ccollect, I thought about enabling backup to remote hosts. Though this sounds like a nice feature ("Backup my notebook to the server now."), in my opinion it is a bad idea to backup to a remote host.

But as more and more people requested this feature, it was implemented, so you have the choice whether you want to use it or not.

#### Reason

If you want to backup TO a remote host, you have to loosen security on it.

Imagine the following situation: You backup your farm of webservers TO a backup host somewhere else. Now one of your webservers which has access to your backup host gets compromised.

Your backup server will be compromised, too.

And the attacker will have access to all data on the other webservers.

#### Doing it securely

Think of it the other way round: The backup server (now behind a firewall, not accessable from outside) connects to the webservers and pulls the data from them. If someone gets access to one of the webservers, this person will perhaps not even see your machine. If the attacker sees connections from a host to the compromised machine, she will not be able to log in on the backup machine. All other backups are still secure.

### Incompatibilities and changes

#### Versions 0.9 and 1.0

- Added "Error: " prefix in _exit_err()

#### Versions 0.8 and 0.9

- Renamed script to ccollect (.sh is not needed)
- Removed feature to backup to a host via ccollect, added new tool (FIXME: insert name here) that takes care of this via tunnel
- Perhaps creating subdirectory of source name (idea from Stefan Schlörholz)

#### Versions 0.7 and 0.8

The argument order changed:

- Old: "<interval name> [args] <sources to backup>"
- New: "[args] <interval name> <sources to backup>"

If you did not use arguments (most people do not), nothing will change for you.

Deletion of incomplete backups using the delete_incomplete option

- Old: Only incomplete backups from the current interval have been removed
- New: All incomplete backups are deleted

Support for standard values

- Old: no support
- New: Options in $CCOLLECT_CONF/defaults are used as defaults (see below)

#### Versions 0.6 and 0.7

The format of `destination` changed:

- Before 0.7 it was a (link to a) directory
- As of 0.7 it is a textfile containing the destination

You can update your configuration using `tools/config-pre-0.7-to-0.7.sh`.

Added remote_host

- As of 0.7 it is possible to backup to hosts (see section remote_host below).

#### Versions 0.5 and 0.6

The format of `rsync_options` changed:

- Before 0.6 it was whitespace delimeted
- As of 0.6 it is newline seperated (so you can pass whitespaces to `rsync`)

You can update your configuration using `tools/config-pre-0.6-to-0.6.sh`.

The name of the backup directories changed:

- Before 0.6: "date +%Y-%m-%d-%H%M"
- As of 0.6: "date +%Y%m%d-%H%M" (better readable, date is closer together)

For the second change there is no updated needed, as XXXX- is always before XXXXX (- comes before digit).

#### Versions 0.4 and 0.5

Not a real incompatibilty, but seems to fit in this section:

0.5 does NOT require

- PaX
- bc

anymore!

#### Versions < 0.4 and 0.4

Since `ccollect` 0.4 there are several incompatibilities with earlier versions:

List of incompatibilities

- `pax` (Posix) is now required, `cp -al` (GNU specific) is removed
- "interval" was written with two l (ell), which is wrong in English
- Changed the name of backup directories, removed the colon in the interval
- ccollect will now exit when preexec returns non-zero
- ccollect now reports when postexec returns non-zero

You can convert your old configuration directory using `config-pre-0.4-to-0.4.sh`, which can be found in the tools/ subdirectory:

    [10:05] hydrogenium:ccollect-0.4# ./tools/config-pre-0.4-to-0.4.sh /etc/ccollect

## Quick start

For those who do not want to read the whole long document:

    # get latest ccollect tarball from http://www.nico.schottelius.org/software/ccollect/
    # replace value for CCV with the current version
    export CCV=0.8.1

    #
    # replace 'wget' with 'fetch' on bsd
    #
    holen=wget
    "$holen" http://www.nico.schottelius.org/software/ccollect/ccollect-${CCV}.tar.bz2

    # extract the tarball, change to the newly created directory
    tar -xvjf ccollect-${CCV}.tar.bz2
    cd ccollect-${CCV}

    # create mini-configuration
    # first create directory structure
    mkdir -p miniconfig/defaults/intervals
    mkdir    miniconfig/sources

    # create sample intervals
    echo 2 > miniconfig/defaults/intervals/testinterval
    echo 3 > miniconfig/defaults/intervals/testinterval2

    # create destination directory, where the backups will be kept
    mkdir ~/DASI

    # create sample source, which will be saved
    mkdir miniconfig/sources/testsource

    # We will save '/bin' to the directory '~/DASI'
    echo '/bin' > miniconfig/sources/testsource/source

    # configure ccollect to use ~/DASI as destination
    echo ~/DASI > miniconfig/sources/testsource/destination

    # We want to see what happens and also a small summary at the end
    touch miniconfig/sources/testsource/verbose
    touch miniconfig/sources/testsource/summary

    echo "do the backup, twice"
    CCOLLECT_CONF=./miniconfig ./ccollect.sh testinterval testsource
    CCOLLECT_CONF=./miniconfig ./ccollect.sh testinterval testsource

    echo "the third time ccollect begins to remove old backups"
    echo -n "Hit enter to see it"
    read
    CCOLLECT_CONF=./miniconfig ./ccollect.sh testinterval testsource

    echo "Now we add another interval, ccollect should clone from existent ones"
    echo -n "Hit enter to see it"
    read
    CCOLLECT_CONF=./miniconfig ./ccollect.sh testinterval2 testsource

    echo "Let's see how much space we used with two backups and compare it to /bin"
    du -s ~/DASI /bin

    # report success
    echo "Please report success using ./tools/report_success.sh"

Cutting and pasting the complete section above to your shell will result in the download of ccollect, the creation of a sample configuration and the execution of some backups.

## Requirements

### Installing ccollect

For the installation you need at least

- the latest ccollect package (http://www.nico.schottelius.org/software/ccollect/)
- either `cp` and `chmod` or `install`
- for more comfort: `make`
- for rebuilding the generated documentation: additionally `asciidoc`

### Using ccollect

Running ccollect requires the following tools to be installed:

- `date`
- `rsync`
- `ssh` (if you want to use rsync over ssh, which is recommened for security)

## Installing

Either type make install or simply copy it to a directory in your $PATH and execute chmod 0755 /path/to/ccollect.sh. If you like to use the new management scripts (available since 0.6), copy the following scripts to a directory in $PATH:

- `tools/ccollect_add_source.sh`
- `tools/ccollect_analyse_logs.sh.sh`
- `tools/ccollect_delete_source.sh`
- `tools/ccollect_list_intervals.sh`
- `tools/ccollect_logwrapper.sh`

After having installed and used ccollect, report success using ./tools/report_success.sh.

## Configuring

For configuration aid have a look at the above mentioned tools, which can assist you quite well. When you are successfully using `ccollect`, I would be happy if you add a link to your website, stating "I backup with ccollect", which points to the ccollect homepage. So more people now about ccollect, use it and improve it. You can also report success using `tools/report_success.sh`.

### Runtime options

`ccollect` looks for its configuration in /etc/ccollect or, if set, in the directory specified by the variable $CCOLLECT_CONF:

    # sh-compatible (dash, zsh, mksh, ksh, bash, ...)
    $ CCOLLECT_CONF=/your/config/dir ccollect.sh ...

    # csh
    $ ( setenv CCOLLECT_CONF /your/config/dir ; ccollect.sh ... )

When you start `ccollect`, you have to specify in which interval to backup (daily, weekly, yearly; you can specify the names yourself, see below) and which sources to backup (or -a to backup all sources).

The interval specifies how many backups are kept.

There are also some self-explanatory parameters you can pass to ccollect, simply use `ccollect.sh --help` for info.

### General configuration

The general configuration can be found in $CCOLLECT_CONF/defaults or /etc/ccollect/defaults. All options specified there are generally valid for all source definitions, although the values can be overwritten in the source configuration.

All configuration entries are plain-text files (use UTF-8 for non-ascii characters).

#### Interval definition

The interval definition can be found in $CCOLLECT_CONF/defaults/intervals/ or /etc/ccollect/defaults/intervals. Each file in this directory specifies an interval. The name of the file is the same as the name of the interval: `intervals/'<interval name>'`.

The content of this file should be a single line containing a number. This number defines how many versions of this interval are kept.

Example:

       [10:23] zaphodbeeblebrox:ccollect-0.2% ls -l conf/defaults/intervals/
       insgesamt 12
       -rw-r--r--  1 nico users 3 2005-12-08 10:24 daily
       -rw-r--r--  1 nico users 3 2005-12-08 11:36 monthly
       -rw-r--r--  1 nico users 2 2005-12-08 11:36 weekly
       [10:23] zaphodbeeblebrox:ccollect-0.2% cat conf/defaults/intervals/*
       28
       12
       4

This means to keep 28 daily backups, 12 monthly backups and 4 weekly.

#### General pre- and post-execution

If you add $CCOLLECT_CONF/defaults/`pre_exec` or /etc/ccollect/defaults/`pre_exec` (same with `post_exec`), `ccollect` will start `pre_exec` before the whole backup process and `post_exec` after backup of all sources is done.

If `pre_exec` exits with a non-zero return code, the whole backup process will be aborted.

The `pre_exec` and `post_exec` script can access the following exported variables:

- INTERVAL: the interval selected (`daily`)
- no_sources: number of sources to backup (`2`)
- source_$no: name of the source, $no starts at 0 (`$source_0`)

The following example describes how to report free disk space in human readable format before and after the whole backup process:

    [13:00] hydrogenium:~# mkdir -p /etc/ccollect/defaults/
    [13:00] hydrogenium:~# echo '#!/bin/sh' >  /etc/ccollect/defaults/pre_exec
    [13:01] hydrogenium:~# echo ''          >> /etc/ccollect/defaults/pre_exec
    [13:01] hydrogenium:~# echo 'df -h'     >> /etc/ccollect/defaults/pre_exec
    [13:01] hydrogenium:~# chmod 0755 /etc/ccollect/defaults/pre_exec
    [13:01] hydrogenium:~# ln -s /etc/ccollect/defaults/pre_exec /etc/ccollect/defaults/post_exec

### Source configuration

Each source configuration exists in $CCOLLECT_CONF/sources/$name or /etc/ccollect/sources/$name.

The name you choose for the subdirectory describes the source.

Each source contains at least the following files:

- `source` (a text file containing the `rsync` compatible path to backup)
- `destination` (a text file containing the directory we should backup to)

Additionally a source may have the following files:

- `pre_exec` program to execute before backing up this source
- `post_exec` program to execute after backing up this source
- `verbose` whether to be verbose (passes -v to `rsync`)
- `very_verbose` be very verbose (`mkdir -v`, `rm -v` and `rsync -vv`)
- `summary` create a transfer summary when `rsync` finished
- `exclude` exclude list for `rsync`. newline seperated list.
- `rsync_options` extra options for `rsync`. newline seperated list.
- `delete_incomplete` delete incomplete backups
- `remote_host` host to backup to
- `rsync_failure_codes` list of rsync exit codes that indicate complete failure
- `mtime` Sort backup directories based on their modification time
- `quiet_if_down` Suppress error messages if source is not connectable

Example:

       [10:47] zaphodbeeblebrox:ccollect-0.2% ls -l  conf/sources/testsource2
       insgesamt 12
       lrwxrwxrwx  1 nico users   20 2005-11-17 16:44 destination
       -rw-r--r--  1 nico users   62 2005-12-07 17:43 exclude
       drwxr-xr-x  2 nico users 4096 2005-12-07 17:38 intervals
       -rw-r--r--  1 nico users   15 2005-11-17 16:44 source
       [10:47] zaphodbeeblebrox:ccollect-0.2% cat conf/sources/testsource2/exclude
       openvpn-2.0.1.tar.gz
       nicht_reinnehmen
       etwas mit leerzeichenli
       [10:47] zaphodbeeblebrox:ccollect-0.2% ls -l  conf/sources/testsource2/intervals
       insgesamt 4
       -rw-r--r--  1 nico users 2 2005-12-07 17:38 daily
       [10:48] zaphodbeeblebrox:ccollect-0.2% cat conf/sources/testsource2/intervals/daily
       5
       [10:48] zaphodbeeblebrox:ccollect-0.2% cat conf/sources/testsource2/source
       /home/nico/vpn

#### Default options

If you add $CCOLLECT_CONF/defaults/`option_name`, the value will be used in abscence of the option in a source. If you want to prevent the default value to be used in a source, you can create the file $CCOLLECT_CONF/sources/$name/`no_option_name` (i.e. prefix it with no_.

Example:

       [9:04] ikn2:ccollect% touch conf/defaults/verbose
       [9:04] ikn2:ccollect% touch conf/sources/local/no_verbose

This enables the verbose option for all sources, but disables it for the source local.

If an option is specified in the defaults folder and in the source, the source specific version overrides the default one:

Example:

       [9:05] ikn2:ccollect% echo "backup-host" > conf/defaults/remote_host
       [9:05] ikn2:ccollect% echo "different-host" > conf/sources/local/remote_host

You can use all source options as defaults, with the exception of

- `source`
- `destination`
- `pre_exec`
- `post_exec`

#### Detailed description of "source"

`source` describes a `rsync` compatible source (one line only).

For instance backup_user@foreign_host:/home/server/video. To use the `rsync` protocol without the `ssh`-tunnel, use rsync::USER@HOST/SRC. For more information have a look at the manpage of `rsync`(1).

#### Detailed description of "destination"

`destination` must be a text file containing the destination directory. `destination` USED to be a link to the destination directory in earlier versions, so do not be confused if you see such examples.

Example:

       [11:36] zaphodbeeblebrox:ccollect-0.2% cat conf/sources/testsource2/destination
       /home/nico/backupdir

#### Detailed description of "remote_host"

`remote_host` must be a text file containing the destination host. If this file is existing, you are backing up your data TO this host and not to you local host.

Warning: You need to have `ssh` access to the remote host. `rsync` and `ccollect` will connect to that host via `ssh`. `ccollect` needs the shell access, because it needs to find out how many backups exist on the remote host and to be able to delete them.

Example:

       [10:17] denkbrett:ccollect-0.7.0% cat conf/sources/remote1/remote_host
       home.schottelius.org

It may contain all the ssh-specific values like myuser@yourhost.ch.

#### Detailed description of "verbose"

`verbose` tells `ccollect` that the log should contain verbose messages.

If this file exists in the source specification -v will be passed to `rsync`.

Example:

       [11:35] zaphodbeeblebrox:ccollect-0.2% touch conf/sources/testsource1/verbose

#### Detailed description of "very_verbose"

`very_verbose` tells `ccollect` that it should log very verbosely.

If this file exists in the source specification -v will be passed to `rsync`, `rm` and `mkdir`.

Example:

       [23:67] nohost:~% touch conf/sources/testsource1/very_verbose

#### Detailed description of "summary"

If you create the file `summary` in the source definition, `ccollect` will present you a nice summary at the end.

    backup:~# touch /etc/ccollect/sources/root/summary
    backup:~# ccollect.sh werktags root
    ==> ccollect.sh: Beginning backup using interval werktags <==
    [root] Beginning to backup this source ...
    [root] Currently 3 backup(s) exist, total keeping 50 backup(s).
    [root] Beginning to backup, this may take some time...
    [root] Hard linking...
    [root] Transferring files...
    [root]
    [root] Number of files: 84183
    [root] Number of files transferred: 32
    [root] Total file size: 26234080536 bytes
    [root] Total transferred file size: 9988252 bytes
    [root] Literal data: 9988252 bytes
    [root] Matched data: 0 bytes
    [root] File list size: 3016771
    [root] File list generation time: 1.786 seconds
    [root] File list transfer time: 0.000 seconds
    [root] Total bytes sent: 13009119
    [root] Total bytes received: 2152
    [root]
    [root] sent 13009119 bytes  received 2152 bytes  2891393.56 bytes/sec
    [root] total size is 26234080536  speedup is 2016.26
    [root] Successfully finished backup.
    ==> Finished ccollect.sh <==

You could also combine it with `verbose` or `very_verbose`, but these already print some statistics (though not all / the same as presented by `summary`).

#### Detailed description of "exclude"

`exclude` specifies a list of paths to exclude. The entries are seperated by a newline (\n).

Example:

       [11:35] zaphodbeeblebrox:ccollect-0.2% cat conf/sources/testsource2/exclude
       openvpn-2.0.1.tar.gz
       nicht_reinnehmen
       etwas mit leerzeichenli
       something with spaces is not a problem

#### Detailed description of "intervals/"

When you create the subdirectory `intervals/` in your source configuration directory, you can specify individiual intervals for this specific source. Each file in this directory describes an interval.

Example:

       [11:37] zaphodbeeblebrox:ccollect-0.2% ls -l conf/sources/testsource2/intervals/
       insgesamt 8
       -rw-r--r--  1 nico users 2 2005-12-07 17:38 daily
       -rw-r--r--  1 nico users 3 2005-12-14 11:33 yearly
       [11:37] zaphodbeeblebrox:ccollect-0.2% cat  conf/sources/testsource2/intervals/*
       5
       20

#### Detailled description of "rsync_options"

When you create the file `rsync_options` in your source configuration, all the parameters in this file will be passed to rsync. This way you can pass additional options to rsync. For instance you can tell rsync to show progress ("--progress"), or which -password-file ("--password-file") to use for automatic backup over the rsync-protocol.

Example:

       [23:42] hydrogenium:ccollect-0.2% cat conf/sources/test_rsync/rsync_options
       --password-file=/home/user/backup/protected_password_file

#### Detailled description of "pre_exec" and "post_exec"

When you create `pre_exec` and / or `post_exec` in your source configuration, `ccollect` will execute this command before and respectively after doing the backup for this specific source. If you want to have pre-/post-exec before and after all backups, see above for general configuration.

If `pre_exec` exits with a non-zero return code, the backup process of `this source` will be aborted (i.e. backup skipped).

The `post_exec` script can access the following exported variables from ccollect:

- name: name of the source that is being backed up
- destination_name: contains the base directory name (`daily.20091031-1013.24496`)
- destination_dir: full path (`/tmp/ccollect/daily.20091031-1013.24496`)
- destination_full: like destination_dir, but prepended with the remote_host, if set (`host:/tmp/ccollect/daily.20091031-1013.24496` or `/tmp/ccollect/daily.20091031-1013.24496`)

Example:

    [13:09] hydrogenium:ccollect-0.3% cat conf/sources/with_exec/pre_exec
    #!/bin/sh

    # Show whats free before
    df -h
    [13:09] hydrogenium:ccollect-0.3% cat conf/sources/with_exec/post_exec
    #!/bin/sh

    # Show whats free after
    df -h

#### Detailed description of "delete_incomplete"

If you create the file `delete_incomplete` in a source specification directory, `ccollect` will look for incomplete backups (when the whole `ccollect` process was interrupted) and remove them. Without this file `ccollect` will only warn the user.

#### Detailed description of "rsync_failure_codes"

If you have the file `rsync_failure_codes` in your source configuration directory, it should contain a newline-separated list of numbers representing rsync exit codes. If rsync exits with any code in this list, a marker will be left in the destination directory indicating failure of this backup. If you have enabled delete_incomplete, then this backup will be deleted during the next ccollect run on the same interval.

#### Detailed description of "mtime"

By default, ccollect.sh chooses the most recent backup directory for cloning or the oldest for deletion based on the directory’s last change time (ctime). With this option, the sorting is done based on modification time (mtime). With this version of ccollect, the ctime and mtime of your backups will normally be the same and this option has no effect. However, if you, for example, move your backups to another hard disk using cp -a or rsync -a, you should use this option because the ctimes are not preserved during such operations.

If you have any backups in your repository made with ccollect version 0.7.1 or earlier, do not use this option.

#### Detailed description of "quiet_if_down"

By default, ccollect.sh emits a series of error messages if a source is not connectable. With this option enabled, ccollect still reports that the source is not connectable but the associated error messages generated by rsync or ssh are suppressed. You may want to use this option for sources, like notebook PCs, that are often disconnected.

## Hints

### Smart logging

Since ccollect-0.6.1 you can use the ccollect-logwrapper.sh(1) for logging. You call it the same way you call ccollect.sh and it will create a logfile containing the output of ccollect.sh. For more information look at the manpage ccollect-logwrapper. The following is an example running ccollect-logwrapper.sh:

    u0219 ~ # ~chdscni9/ccollect-logwrapper.sh daily u0160.nshq.ch.netstream.com
    ccollect-logwrapper.sh (11722): Starting with arguments: daily u0160.nshq.ch.netstream.com
    ccollect-logwrapper.sh (11722): Finished.

### Using a different ssh port

Mostly easy is to use your ~/.ssh/config file:

    host mx2.schottelius.org
       Port 2342

If you only use that port for backup only and normally want to use another port, you can add HostName and "HostKeyAlias" (if you also have different keys on the different ports):

    Host hhydrogenium
       Hostname bruehe.schottelius.org
       Port 666
       HostKeyAlias hydrogenium

    Host bruehe
       Hostname bruehe.schottelius.org
       Port 22
       HostKeyAlias bruehe.schottelius.org

### Using source names or interval in pre_/post_exec scripts

The pre-/post_exec scripts can access some internal variables from `ccollect`:

- INTERVAL: The interval specified on the command line
- no_sources: number of sources
- source_$NUM: the name of the source
- name: the name of the currently being backuped source (not available for generic pre_exec script)

Only available for `post_exec`:

- remote_host: name of host we backup to (empty if unused)

### Using rsync protocol without ssh

When you have a computer with little computing power, it may be useful to use rsync without ssh, directly using the rsync protocol (specify user@host::share in `source`). You may wish to use `rsync_options` to specify a password file to use for automatic backup.

Example:

    backup:~# cat /etc/ccollect/sources/sample.backup.host.org/source
    backup@webserver::backup-share

    backup:~# cat /etc/ccollect/sources/sample.backup.host.org/rsync_options
    --password-file=/etc/ccollect/sources/sample.backup.host.org/rsync_password

    backup:~# cat /etc/ccollect/sources/sample.backup.host.org/rsync_password
    this_is_the_rsync_password

This hint was reported by Daniel Aubry.

### Not excluding top-level directories

When you exclude "/proc" or "/mnt" from your backup, you may run into trouble when you restore your backup. When you use "/proc/*" or "/mnt/\*" instead, `ccollect` will backup empty directories.

### Note

When those directories contain hidden files (those beginning with a dot (.)), they will still be transferred!

This hint was reported by Marcus Wagner.

### Re-using already created rsync-backups

If you used `rsync` directly before you use `ccollect`, you can use this old backup as initial backup for `ccollect`: You simply move it into a directory below the destination directory and name it "interval.0".

Example:

    backup:/home/backup/web1# ls
    bin   dev  etc   initrd  lost+found  mnt  root  srv  usr  vmlinuz
    boot  doc  home  lib     media       opt  sbin  tmp  var  vmlinuz.old

    backup:/home/backup/web1# mkdir daily.0

    # ignore error about copying to itself
    backup:/home/backup/web1# mv * daily.0 2>/dev/null

    backup:/home/backup/web1# ls
    daily.0

Now you can use /home/backup/web1 as the `destination` for the backup.

### Note

It does not matter anymore how you name your directory, as `ccollect` uses the -c option from `ls` to find out which directory to clone from.

### Note

Older versions (pre 0.6, iirc) had a problem, if you named the first backup something like "daily.initial". It was needed to use the "0" (or some number that is lower than the current year) as extension. `ccollect` used `sort` to find the latest backup. `ccollect` itself uses interval.YEARMONTHDAY-HOURMINUTE.PID. This notation was always before "daily.initial", as numbers are earlier in the list which is produced by `sort`. So, if you had a directory named "daily.initial", `ccollect` always diffed against this backup and transfered and deleted files which where deleted in previous backups. This means you simply wasted resources, but your backup had beer complete anyway.

### Using pre_/post_exec

Your pre_/post_exec script does not need to be a script, you can also use a link to

- an existing program
- an already written script

The only requirement is that it is executable.

### Using source specific interval definitions

When you are backing up multiple hosts via cron each night, it may be a problem that host "big_server" may only have 4 daily backups, because otherwise its backup device will be full. But for all other hosts you want to keep 20 daily backups. In this case you would create `/etc/ccollect/default/intervals/daily` containing "20" and `/etc/ccollect/sources/big_server/intervals/daily` containing "4".

Source specific intervals always overwrite the default values. If you have to specify it individually for every host, because of different requirements, you can even omit creating `/etc/ccollect/default/intervals/daily`.

### Comparing backups

If you want to see what changed between two backups, you can use `rsync` directly:

    [12:00] u0255:ddba034.netstream.ch#  rsync -n -a --delete --stats --progress daily.20080324-0313.17841/ daily.20080325-0313.31148/

This results in a listing of changes. Because we pass -n to rsync no transfer is made (i.e. report only mode).

This hint was reported by Daniel Aubry.

### Testing for host reachabilty

If you want to test whether the host you try to backup is reachable, you can use the following script as source specific pre-exec:

    #!/bin/sh
    # ping -c1 -q `cat "/etc/ccollect/sources/$name/source" | cut -d"@" -f2 | cut -d":" -f1`

This prevents the deletion of old backups, if the host is not reachable.

This hint was reported by Daniel Aubry.

### Easy check for errors

If you want to see whether there have been any errors while doing the backup, you can run `ccollect` together with `ccollect_analyse_logs.sh`:

    $ ccollect | ccollect_analyse_logs.sh e

## F.A.Q.

### What happens if one backup is broken or empty?

Let us assume that one backup failed (connection broke or the source hard disk had some failures). Therefore we’ve got one incomplete backup in our history.

`ccollect` will transfer the missing files the next time you use it. This leads to

- more transferred files
- much greater disk space usage, as no hardlinks can be used

If the whole `ccollect` process was interrupted, `ccollect` (since 0.6) can detect that and remove the incomplete backups, so you can clone from a complete backup instead

### When backing up from localhost the destination is also included. Is this a bug?

No. `ccollect` passes your source definition directly to `rsync`. It does not try to analyze it. So it actually does not know if a source comes from local harddisk or from a remote server. And it does not want to. When you backup from the local harddisk (which is perhaps not even a good idea when thinking of security), add the `destination` to source/exclude. (Daniel Aubry reported this problem)

### Why does ccollect say "Permission denied" with my pre-/postexec script?

The most common error is that you have not given your script the correct permissions. Try `chmod 0755 /etc/ccollect/sources/'yoursource'/*_exec``.

### Why does the backup job fail when part of the source is a link?

When a part of your path you specified in the source is a (symbolic, hard links are not possible for directories) link, the backup must fail.

First of all, let us have a look at how it looks like:

    ==> ccollect 0.4: Beginning backup using interval taeglich <==
    [testsource] Sa Apr 29 00:01:55 CEST 2006 Beginning to backup
    [testsource] Currently 0 backup(s) exist(s), total keeping 10 backup(s).
    [testsource] Beginning to backup, this may take some time...
    [testsource] Creating /etc/ccollect/sources/testsource/destination/taeglich.2006-04-29-0001.3874 ...
    [testsource] Sa Apr 29 00:01:55 CEST 2006 Transferring files...
    [testsource] rsync: recv_generator: mkdir "/etc/ccollect/sources/testsource/destination/taeglich.2006-04-29-0001.3874/home/user/nico/projekte/ccollect" failed: No such file or directory (2)
    [testsource] rsync: stat "/etc/ccollect/sources/testsource/destination/taeglich.2006-04-29-0001.3874/home/user/nico/projekte/ccollect" failed: No such file or directory (2)
    [...]

So what is the problem? It is very obvious when you look deeper into it:

    % cat /etc/ccollect/sources/testsource/source
    /home/user/nico/projekte/ccollect/ccollect-0.4
    % ls -l /home/user/nico/projekte
    lrwxrwxrwx 1 nico nico 29 2005-12-02 23:28 /home/user/nico/projekte -> oeffentlich/computer/projekte
    % ls -l /etc/ccollect/sources/testsource/destination/taeglich.2006-04-29-0001.3874/home/user/nico
    lrwxrwxrwx 1 nico nico 29 2006-04-29 00:01 projekte -> oeffentlich/computer/projekte

`rsync` creates the directory structure before it creates the symbolic link. This link now links to something not reachable (dead link). It is impossible to create subdirectories under the broken link.

In conclusion you cannot use paths with a linked part.

However, you can backup directories containing symbolic links (in this case you could backup /home/user/nico, which contains /home/user/nico/projekte and oeffentlich/computer/projekte).

### How can I prevent missing the right time to enter my password?

As `ccollect` first deletes the old backups, it may take some time until `rsync` requests the password for the `ssh` session from you.

The easiest way not to miss that point is running `ccollect` in `screen`, which has the ability to monitor the output for activity. So as soon as your screen beeps, after `ccollect` began to remove the last directory, you can enter your password (have a look at screen(1), especially "C-a M" and "C-a _", for more information).

### Backup fails, if autofs is running, but sources not reachable

If you are trying to backup a system containing paths that are managed by autofs, you may run into this error:

    2009-12-01-23:14:15: ccollect 0.8.1: Beginning backup using interval monatlich
    [ikn] 2009-12-01-23:14:15: Beginning to backup
    [ikn] 2009-12-01-23:14:15: Executing /home/users/nico/ethz/ccollect/sources/ikn/pre_exec ...
    Enter LUKS passphrase:
    [ikn] Command successful.
    [ikn] key slot 0 unlocked.
    [ikn] 2009-12-01-23:14:23: Finished /home/users/nico/ethz/ccollect/sources/ikn/pre_exec (return code 0). [ikn] directory has vanished: "/home/users/nico/privat/firmen/ethz/autofs/projects"
    [ikn] directory has vanished: "/home/users/nico/privat/firmen/ethz/autofs/scratch"
    [ikn] directory has vanished: "/home/users/nico/privat/firmen/ethz/autofs/sgscratch"
    [ikn] directory has vanished: "/home/users/nico/privat/firmen/ethz/autofs/supp"
    [ikn] directory has vanished: "/home/users/nico/privat/firmen/ethz/autofs/sysadmin"
    [ikn] rsync warning: some files vanished before they could be transferred (code 24) at main.c(1057) [sender=3.0.6]
    [ikn] 2009-12-01-23:44:23: Source / is not readable. Skipping.

Thus, if you are unsure whether autofs paths can be mounted during backup, stop autofs in pre_exec and reenable it in post_exec.

## Examples

### A backup host configuration from scratch

    srwali01:~# mkdir /etc/ccollect
    srwali01:~# mkdir -p /etc/ccollect/defaults/intervals/
    srwali01:~# echo 28 > /etc/ccollect/defaults/intervals/taeglich
    srwali01:~# echo 52 > /etc/ccollect/defaults/intervals/woechentlich
    srwali01:~# cd /etc/ccollect/
    srwali01:/etc/ccollect# mkdir sources
    srwali01:/etc/ccollect# cd sources/
    srwali01:/etc/ccollect/sources# ls
    srwali01:/etc/ccollect/sources# mkdir local-root
    srwali01:/etc/ccollect/sources# cd local-root/
    srwali01:/etc/ccollect/sources/local-root# echo / > source
    srwali01:/etc/ccollect/sources/local-root# cat > exclude << EOF
    > /proc
    > /sys
    > /mnt
    > EOF
    srwali01:/etc/ccollect/sources/local-root# echo /mnt/hdbackup/local-root > destination
    srwali01:/etc/ccollect/sources/local-root# mkdir /mnt/hdbackup/local-root
    srwali01:/etc/ccollect/sources/local-root# ccollect.sh taeglich local-root
    /o> ccollect.sh: Beginning backup using interval taeglich
    /=> Beginning to backup "local-root" ...
    |-> 0 backup(s) already exist, keeping 28 backup(s).

After that, I added some more sources:

    srwali01:~# cd /etc/ccollect/sources
    srwali01:/etc/ccollect/sources# mkdir windos-wl6
    srwali01:/etc/ccollect/sources# cd windos-wl6/
    srwali01:/etc/ccollect/sources/windos-wl6# echo /mnt/win/SYS/WL6 > source
    srwali01:/etc/ccollect/sources/windos-wl6# echo /mnt/hdbackup/wl6 > destination
    srwali01:/etc/ccollect/sources/windos-wl6# mkdir /mnt/hdbackup/wl6
    srwali01:/etc/ccollect/sources/windos-wl6# cd ..
    srwali01:/etc/ccollect/sources# mkdir windos-daten
    srwali01:/etc/ccollect/sources/windos-daten# echo /mnt/win/Daten > source
    srwali01:/etc/ccollect/sources/windos-daten# echo /mnt/hdbackup/windos-daten > destination
    srwali01:/etc/ccollect/sources/windos-daten# mkdir /mnt/hdbackup/windos-daten

    # Now add some remote source
    srwali01:/etc/ccollect/sources/windos-daten# cd ..
    srwali01:/etc/ccollect/sources# mkdir srwali03
    srwali01:/etc/ccollect/sources# cd srwali03/
    srwali01:/etc/ccollect/sources/srwali03# cat > exclude << EOF
    > /proc
    > /sys
    > /mnt
    > /home
    > EOF
    srwali01:/etc/ccollect/sources/srwali03# echo 'root@10.103.2.3:/' > source
    srwali01:/etc/ccollect/sources/srwali03# echo /mnt/hdbackup/srwali03 > destination
    srwali01:/etc/ccollect/sources/srwali03# mkdir /mnt/hdbackup/srwali03

### Using hard-links requires less disk space

    # du (coreutils) 5.2.1
    [10:53] srsyg01:sources% du -sh ~/backupdir
    4.6M    /home/nico/backupdir
    [10:53] srsyg01:sources% du -sh ~/backupdir/*
    4.1M    /home/nico/backupdir/daily.2005-12-08-10:52.28456
    4.1M    /home/nico/backupdir/daily.2005-12-08-10:53.28484
    4.1M    /home/nico/backupdir/daily.2005-12-08-10:53.28507
    4.1M    /home/nico/backupdir/daily.2005-12-08-10:53.28531
    4.1M    /home/nico/backupdir/daily.2005-12-08-10:53.28554
    4.1M    /home/nico/backupdir/daily.2005-12-08-10:53.28577

    srwali01:/etc/ccollect/sources# du -sh /mnt/hdbackup/wl6/
    186M    /mnt/hdbackup/wl6/
    srwali01:/etc/ccollect/sources# du -sh /mnt/hdbackup/wl6/*
    147M    /mnt/hdbackup/wl6/taeglich.2005-12-08-14:42.312
    147M    /mnt/hdbackup/wl6/taeglich.2005-12-08-14:45.588

The backup of our main fileserver:

    backup:~# df -h /home/backup/srsyg01/
    Filesystem            Size  Used Avail Use% Mounted on
    /dev/mapper/backup--01-srsyg01
                          591G  451G  111G  81% /home/backup/srsyg01
    backup:~# du -sh /home/backup/srsyg01/*
    432G    /home/backup/srsyg01/daily.2006-01-24-01:00.15990
    432G    /home/backup/srsyg01/daily.2006-01-26-01:00.30152
    434G    /home/backup/srsyg01/daily.2006-01-27-01:00.4596
    435G    /home/backup/srsyg01/daily.2006-01-28-01:00.11998
    437G    /home/backup/srsyg01/daily.2006-01-29-01:00.19115
    437G    /home/backup/srsyg01/daily.2006-01-30-01:00.26405
    438G    /home/backup/srsyg01/daily.2006-01-31-01:00.1148
    439G    /home/backup/srsyg01/daily.2006-02-01-01:00.8321
    439G    /home/backup/srsyg01/daily.2006-02-02-01:00.15383
    439G    /home/backup/srsyg01/daily.2006-02-03-01:00.22567
    16K     /home/backup/srsyg01/lost+found
    backup:~# du --version | head -n1
    du (coreutils) 5.2.1

Newer versions of du also detect the hardlinks, so we can even compare the sizes directly with du:

    [8:16] eiche:~# du --version | head -n 1
    du (GNU coreutils) 5.93
    [8:17] eiche:schwarzesloch# du -slh hydrogenium/*
    19G     hydrogenium/durcheinander.0
    18G     hydrogenium/durcheinander.2006-01-17-00:27.13820
    19G     hydrogenium/durcheinander.2006-01-25-23:18.31328
    19G     hydrogenium/durcheinander.2006-01-26-00:11.3332
    [8:22] eiche:schwarzesloch# du -sh hydrogenium/*
    19G     hydrogenium/durcheinander.0
    12G     hydrogenium/durcheinander.2006-01-17-00:27.13820
    1.5G    hydrogenium/durcheinander.2006-01-25-23:18.31328
    200M    hydrogenium/durcheinander.2006-01-26-00:11.3332

In the second report (without -l) the sizes include the space the inodes of the hardlinks allocate.

### A collection of backups on the backup server

All the data of my important hosts is backuped to eiche into /mnt/schwarzesloch/backup:

    [9:24] eiche:backup# ls *
    creme:
    woechentlich.2006-01-26-22:22.4153   woechentlich.2006-02-12-11:48.2461
    woechentlich.2006-01-26-22:23.4180   woechentlich.2006-02-18-23:00.7898
    woechentlich.2006-02-05-02:43.14281  woechentlich.2006-02-25-23:00.13480
    woechentlich.2006-02-06-00:24.15509  woechentlich.2006-03-04-23:00.25439

    hydrogenium:
    durcheinander.2006-01-27-11:16.6391   durcheinander.2006-02-13-01:07.2895
    durcheinander.2006-01-30-19:29.9505   durcheinander.2006-02-17-08:20.6707
    durcheinander.2006-01-30-22:27.9623   durcheinander.2006-02-24-16:24.12461
    durcheinander.2006-02-03-09:52.12885  durcheinander.2006-03-03-19:17.18075
    durcheinander.2006-02-05-23:00.15068  durcheinander.2006-03-17-22:41.5007

    scice:
    woechentlich.2006-02-04-10:32.13766  woechentlich.2006-02-16-23:00.6185
    woechentlich.2006-02-05-23:02.15093  woechentlich.2006-02-23-23:00.11783
    woechentlich.2006-02-06-08:22.15994  woechentlich.2006-03-02-23:00.17346
    woechentlich.2006-02-06-19:40.16321  woechentlich.2006-03-09-23:00.29317
    woechentlich.2006-02-12-11:51.2514   woechentlich.2006-03-16-23:00.4218

And this incremental backup and the archive are copied to an external usb harddisk (attention: you should really use -H to backup the backup):

    [9:23] eiche:backup# df -h
    Filesystem            Size  Used Avail Use% Mounted on
    rootfs                 14G  8.2G  4.9G  63% /
    /dev/root              14G  8.2G  4.9G  63% /
    /dev/root              14G  8.2G  4.9G  63% /dev/.static/dev
    tmpfs                  10M  444K  9.6M   5% /dev
    /dev/hdh               29G  3.7M   29G   1% /mnt/datenklo
    tmpfs                 110M  4.0K  110M   1% /dev/shm
    /dev/mapper/nirvana   112G   90G   23G  81% /mnt/datennirvana
    /dev/mapper/schwarzes-loch
                          230G  144G   86G  63% /mnt/schwarzesloch
    /dev/mapper/archiv     38G   20G   19G  52% /mnt/archiv
    /dev/mapper/usb-backup
                          280G   36M  280G   1% /mnt/usb/backup
    [9:24] eiche:backup# cat ~/bin/sync-to-usb
    DDIR=/mnt/usb/backup

    rsync -av -H --delete /mnt/schwarzesloch/ "$DDIR/schwarzesloch/"

    rsync -av -H --delete /mnt/archiv/ "$DDIR/archiv/"

### Processes running when doing ccollect -j

Truncated output from `ps axuwwwf`:

       S+   11:40   0:00  |   |   |   \_ /bin/sh /usr/local/bin/ccollect.sh daily -j ddba034 ddba045 ddba046 ddba047 ddba049 ddna010 ddna011
       S+   11:40   0:00  |   |   |       \_ /bin/sh /usr/local/bin/ccollect.sh daily ddba034
       S+   11:40   0:00  |   |   |       |   \_ /bin/sh /usr/local/bin/ccollect.sh daily ddba034
       R+   11:40  23:40  |   |   |       |   |   \_ rsync -a --delete --numeric-ids --relative --delete-excluded --link-dest=/home/server/backup/ddba034
       S+   11:40   0:00  |   |   |       |   |       \_ ssh -l root ddba034.netstream.ch rsync --server --sender -vlogDtprR --numeric-ids . /
       S+   11:41   0:11  |   |   |       |   |       \_ rsync -a --delete --numeric-ids --relative --delete-excluded --link-dest=/home/server/backup/ddb
       S+   11:40   0:00  |   |   |       |   \_ /bin/sh /usr/local/bin/ccollect.sh daily ddba034
       S+   11:40   0:00  |   |   |       |       \_ sed s:^:\[ddba034\] :
       S+   11:40   0:00  |   |   |       \_ /bin/sh /usr/local/bin/ccollect.sh daily ddba045
       S+   11:40   0:00  |   |   |       |   \_ /bin/sh /usr/local/bin/ccollect.sh daily ddba045
       R+   11:40   0:02  |   |   |       |   |   \_ rm -rf /etc/ccollect/sources/ddba045/destination/daily.2006-10-19-1807.6934
       S+   11:40   0:00  |   |   |       |   \_ /bin/sh /usr/local/bin/ccollect.sh daily ddba045
       S+   11:40   0:00  |   |   |       |       \_ sed s:^:\[ddba045\] :
       S+   11:40   0:00  |   |   |       \_ /bin/sh /usr/local/bin/ccollect.sh daily ddba046
       S+   11:40   0:00  |   |   |       |   \_ /bin/sh /usr/local/bin/ccollect.sh daily ddba046
       R+   11:40   0:02  |   |   |       |   |   \_ rm -rf /etc/ccollect/sources/ddba046/destination/daily.2006-10-19-1810.7072
       S+   11:40   0:00  |   |   |       |   \_ /bin/sh /usr/local/bin/ccollect.sh daily ddba046
       S+   11:40   0:00  |   |   |       |       \_ sed s:^:\[ddba046\] :
       S+   11:40   0:00  |   |   |       \_ /bin/sh /usr/local/bin/ccollect.sh daily ddba047
       S+   11:40   0:00  |   |   |       |   \_ /bin/sh /usr/local/bin/ccollect.sh daily ddba047
       R+   11:40   0:03  |   |   |       |   |   \_ rm -rf /etc/ccollect/sources/ddba047/destination/daily.2006-10-19-1816.7268
       S+   11:40   0:00  |   |   |       |   \_ /bin/sh /usr/local/bin/ccollect.sh daily ddba047
       S+   11:40   0:00  |   |   |       |       \_ sed s:^:\[ddba047\] :
       S+   11:40   0:00  |   |   |       \_ /bin/sh /usr/local/bin/ccollect.sh daily ddba049
       S+   11:40   0:00  |   |   |       |   \_ /bin/sh /usr/local/bin/ccollect.sh daily ddba049
       D+   11:40   0:03  |   |   |       |   |   \_ rm -rf /etc/ccollect/sources/ddba049/destination/daily.2006-10-19-1821.7504
       S+   11:40   0:00  |   |   |       |   \_ /bin/sh /usr/local/bin/ccollect.sh daily ddba049
       S+   11:40   0:00  |   |   |       |       \_ sed s:^:\[ddba049\] :
       S+   11:40   0:00  |   |   |       \_ /bin/sh /usr/local/bin/ccollect.sh daily ddna010
       S+   11:40   0:00  |   |   |       |   \_ /bin/sh /usr/local/bin/ccollect.sh daily ddna010
       R+   11:40   0:03  |   |   |       |   |   \_ rm -rf /etc/ccollect/sources/ddna010/destination/daily.2006-10-19-1805.6849
       S+   11:40   0:00  |   |   |       |   \_ /bin/sh /usr/local/bin/ccollect.sh daily ddna010
       S+   11:40   0:00  |   |   |       |       \_ sed s:^:\[ddna010\] :
       S+   11:40   0:00  |   |   |       \_ /bin/sh /usr/local/bin/ccollect.sh daily ddna011
       S+   11:40   0:00  |   |   |           \_ /bin/sh /usr/local/bin/ccollect.sh daily ddna011
       R+   12:08   0:00  |   |   |           |   \_ rm -rf /etc/ccollect/sources/ddna011/destination/daily.2006-10-20-1502.7824
       S+   11:40   0:00  |   |   |           \_ /bin/sh /usr/local/bin/ccollect.sh daily ddna011
       S+   11:40   0:00  |   |   |               \_ sed s:^:\[ddna011\] :

As you can see, six processes are deleting old backups, while one backup (ddba034) is already copying data.