Backing up with Amanda on NSLU2

Jurjen Bokma

December 2012

Abstract

Failed attempt to use a LinkSys NSLU2 as a backup server with Amanda and Debian Wheezy


Procedure 10.  Installing Amanda
Procedure 11.  Backing up a local directory
  1. Create directories /home/amanda/slug and deeper, to this effect:

    apprentice@host:~$ root@slug:# tree /home/amanda/slug/
    /home/amanda/slug/
    |-- holding
    |-- state
    |-- log
     -- vtapes
        |-- data -> slot0
        |-- slot0
        |-- slot1
        |-- slot10
        |-- slot2
        |-- slot3
        |-- slot4
        |-- slot5
        |-- slot6
        |-- slot7
        |-- slot8
        |-- slot9
         -- state

    16 directories, 1 file

    All these should be owned by the amanda user(, backup in my case).

  2. Create /etc/amanda/slug-itself/amanda.conf:

    org "slug"
    infofile "/home/amanda/slug/state/curinfo"
    logdir "/home/amanda/slug/state/log"
    indexdir "/home/amanda/slug/state/index"
    dumpuser "root"
    
    tpchanger "chg-disk:/home/amanda/slug/vtapes"
    property "num-slot" "10"
    property "auto-create-slot" "yes"
    property "removable" "no"
    property "mount" "no"
    property "umount" "no"
    labelstr "slug[0-9][0-9]"
    autolabel "slug%%" EMPTY VOLUME_ERROR
    
    tapetype "TEST-TAPE"
    define tapetype TEST-TAPE {
      length 100 mbytes
      filemark 4 kbytes
    }
    
    define dumptype simple-gnutar-local {
        auth "local"
        compress none
        program "GNUTAR"
    }
    
    holdingdisk hd1 {
        directory "/home/amanda/slug/holding"
        use 50 mbytes
        chunksize 1 mbyte
    }
    	

    ... and /etc/amanda/slug-itself/disklist:

    localhost /etc simple-gnutar-local
    	

  3. root@slug:# amcheck slug-itself
    Amanda Tape Server Host Check
    -----------------------------
    Holding disk /home/amanda/slug/holding: 820539392 kB disk space available, using 51200 kB as requested
    found in slot 0: volume 'slug01'
    slot 0: volume 'slug01' is still active and cannot be overwritten
    found in slot 1: contains an empty volume
    slot 1: contains an empty volume
    Will write label 'slug02' to new volume in slot 1.
    NOTE: skipping tape-writable test
    Server check took 15.310 seconds

    Amanda Backup Client Hosts Check
    --------------------------------
    Client check: 1 host checked in 6.227 seconds.  0 problems found.

    (brought to you by Amanda 3.3.1)

  4. Now we should be able to back up /etc:

    root@slug:# amdump slug-itself && echo success
    success

    But when there is no 'tape', the exit status will still be zero, but nothing will have been backed up, so be sure to check:

    root@slug:# amreport slug-itself
    Hostname: slug
    Org     : slug
    Config  : slug-itself
    Date    : December 30, 2012

    These dumps were to tape slug01.
    The next tape Amanda expects to use is: 1 new tape.


    STATISTICS:
                              Total       Full      Incr.   Level:#
                            --------   --------   --------  --------
    Estimate Time (hrs:min)     0:00
    Run Time (hrs:min)          0:01
    Dump Time (hrs:min)         0:00       0:00       0:00
    Output Size (meg)            2.4        2.4        0.0
    Original Size (meg)          2.4        2.4        0.0
    Avg Compressed Size (%)    100.0      100.0        --
    DLEs Dumped                    1          1          0
    Avg Dump Rate (k/s)        224.2      224.2        --

    Tape Time (hrs:min)         0:00       0:00       0:00
    Tape Size (meg)              2.4        2.4        0.0
    Tape Used (%)                2.4        2.4        0.0
    DLEs Taped                     1          1          0
    Parts Taped                    1          1          0
    Avg Tp Write Rate (k/s)   1230.0     1230.0        --

    USAGE BY TAPE:
      Label               Time         Size      %  DLEs Parts
      slug01              0:00        2460k    2.4     1     1

    NOTES:
      planner: Adding new disk localhost:/etc.
      taper: Slot 0 without label can be labeled
      taper: tape slug01 kb 2460 fm 1 [OK]


    DUMP SUMMARY:
                                           DUMPER STATS               TAPER STATS
    HOSTNAME     DISK        L ORIG-kB  OUT-kB  COMP%  MMM:SS   KB/s MMM:SS   KB/s
    -------------------------- ------------------------------------- -------------
    localhost    /etc        0    2460    2460     --    0:11  224.2   0:02 1230.0

    (brought to you by Amanda version 3.3.1)

Procedure 12.  Backing up a remote PC
  1. root@slug:# mkdir -p /home/amanda/remotepc/holding /home/amanda/remotepc/state/{curinfo,index,log} ; for (( i = 0; i <= 10 ; i++)) ; do mkdir -p /home/amanda/remotepc/vtapes/slot$i ; done
    root@slug:# chown -R backup:backup /home/amanda/remotepc/

  2. /etc/amanda/remotepc/amanda.conf

    org "remotepc"
    infofile "/home/amanda/remotepc/state/curinfo"
    logdir "/home/amanda/remotepc/state/log"
    indexdir "/home/amanda/remotepc/state/index"
    dumpuser "root"
    
    tpchanger "chg-disk:/home/amanda/remotepc/vtapes"
    property "num-slot" "10"
    property "auto-create-slot" "yes"
    property "removable" "no"
    property "mount" "no"
    property "umount" "no"
    labelstr "remotepc[0-9][0-9]"
    autolabel "remotepc%%" EMPTY VOLUME_ERROR
    
    tapetype "STD-TAPE"
    define tapetype STD-TAPE {
      length 2 gbytes
      filemark 4 kbytes
    }
    
    define dumptype simple-gnutar-remote {
        auth "ssh"
        ssh_keys "/home/amanda/remotepc/.ssh/id_rsa"
        compress none
        program "GNUTAR"
    }
    
    holdingdisk hd1 {
        directory "/home/amanda/remotepc/holding"
        use 50 mbytes
        chunksize 1 mbyte
    }
    	

    /etc/amanda/remotepc/disklist

    192.168.113.222 /etc simple-gnutar-remote
    	

  3. root@slug:# install -g backup -o backup -m 700 -d /home/amanda/remotepc/.ssh
    root@slug:# su backup -c 'ssh-keygen -t rsa -C "Amanda Server Key" -f /home/amanda/remotepc/.ssh/id_rsa'

    root@pc2bBackedUp:~# install -g backup -o backup -m 700 -d ~backup/.ssh

    And append the contents of /home/amanda/remotepc/.ssh/id_rsa.pub on the server to ~backup/.ssh/authorized_keys on the client.

  4. Both amcheck remotepc and amdump remotepc should now work. And amreport remotepc should give satisfying output.

Procedure 13.  Restoring a remote client
  1. root@pc2bBackedUp:# su backup -c 'ssh-keygen -t rsa -C "Amanda client key" -f ~backup/.ssh/id_rsa'

    ... and configure authorized_keys on server. Ssh from client to server succeeds.

  2. The command amrecover (on the client) fails with a segfault and no error message. Even with

    index_server 192.168.117.222
    tape_server 192.168.117.222
    auth ssh
    ssh_keys "/var/backups/.ssh/id_rsa"
    	

    in /etc/amanda/amanda-client.conf

    For now, this is a show stopper. I'll use rsync for the time being.