Paul Graf wrote:
> I've got a strange problem with my backups.  I'm running Amanda 2.5 on FC4, 
> and the problem lies with one large directory that needs to be backed up.  
> It's over 700 gigs, so it has to span tapes.  Eventually the backup will 
> complete, but I'm getting an average of 3 MB/s.  However, if I back up 
> something smaller (I have a few directories being backed up that are around 
> 100 megs), I get 25 MB/s.  I also did some test tar backups of a few gigs, 
> and those went at around 25 MB/s as well.
> 
> I do have an idea about what is causing the problem, but I'd like to get 
> some input before I try to adjust anything.  My tape library is a Dell LTO-2 
> unit (200GB uncompressed), and going by the amanda.conf comments, I set the 
> chunk size to 20GB.  I have a feeling that this is conflicted by my holding 
> disk space, which is also 20GB.  Would increasing the holding disk space or 
> decreasing the chunk size be helpful?  Here's my amanda.conf:

The backups will go directly to tape (i.e., slowly) if the _entire_ backup
image doesn't fit on the holdingdisk.  The chunksize parameter is just
to prevent having problems with systems lacking largefile support where
you can't create a single file larger than 2GB or so (depending on the
filesystem and OS).  Taper doesn't start writing a DLE to tape until all
of its chunks are collected in the holdingdisk, so in your case where it
won't fit Amanda bypasses the holdingdisk and writes directly to tape.

Increasing the holdingdisk space would only help if you make it larger than
700GB.  One thing that might work for you is splitting up that DLE into
smaller pieces, although you still might want a larger holdingingdisk so
you won't need to split it into as many DLEs.

Frank


> 
> org "DailyBackup"     # your organization name for reports
> 
> mailto "root"         # space separated list of operators at your site
> dumpuser "amandabackup"       # the user to run dumps under
> 
> inparallel 4          # maximum dumpers that will run in parallel (max 63)
>                       # this maximum can be increased at compile-time,
>                       # modifying MAX_DUMPERS in server-src/driverio.h
> dumporder "sssS"      # specify the priority order of each dumper
>                       #   s -> smallest size
>                       #   S -> biggest size
>                       #   t -> smallest time
>                       #   T -> biggest time
>                       #   b -> smallest bandwitdh
>                       #   B -> biggest bandwitdh
>                       # try "BTBTBTBTBTBT" if you are not holding
>                       # disk constrained
> 
> taperalgo first               # The algorithm used to choose which dump image 
> to send
>                       # to the taper.
> 
>                       # Possible values: 
> [first|firstfit|largest|largestfit|smallest|last]
>                       # Default: first.
> 
>                       # first         First in - first out.
>                       # firstfit      The first dump image that will fit on 
> the current tape.
>                       # largest       The largest dump image.
>                       # largestfit    The largest dump image that will fit on 
> the current tape.
>                       # smallest      The smallest dump image.
>                       # last          Last in - first out.
> 
> displayunit "k"               # Possible values: "k|m|g|t"
>                       # Default: k.
>                       # The unit used to print many numbers.
>                       # k=kilo, m=mega, g=giga, t=tera
> 
> netusage  6000 Kbps   # maximum net bandwidth for Amanda, in KB per sec
> 
> dumpcycle 4 weeks     # the number of days in the normal dump cycle
> runspercycle 7 days     # the number of amdump runs in dumpcycle days
>                       # (4 weeks * 5 amdump runs per week -- just weekdays)
> tapecycle 30 tapes    # the number of tapes in rotation
>                       # 4 weeks (dumpcycle) times 5 tapes per week (just
>                       # the weekdays) plus a few to handle errors that
>                       # need amflush and so we do not overwrite the full
>                       # backups performed at the beginning of the previous
>                       # cycle
> 
> bumpsize 20 Mb                # minimum savings (threshold) to bump level 1 
> -> 2
> bumppercent 20                # minimum savings (threshold) to bump level 1 
> -> 2
> bumpdays 1            # minimum days at each level
> bumpmult 4            # threshold = bumpsize * bumpmult^(level-1)
> 
> 
> etimeout 300          # number of seconds per filesystem for estimates.
> #etimeout -600                # total number of seconds for estimates.
> # a positive number will be multiplied by the number of filesystems on
> # each host; a negative number will be taken as an absolute total time-out.
> # The default is 5 minutes per filesystem.
> 
> dtimeout 1800         # number of idle seconds before a dump is aborted.
> 
> ctimeout 90           # maximum number of seconds that amcheck waits
>                       # for each client host
> 
> tapebufs 20
> 
> runtapes 7            # number of tapes to be used in a single run of amdump
> tpchanger "chg-zd-mtx"        # the tape-changer glue script
> tapedev "/dev/nst0"   # the no-rewind tape device to be used
> #rawtapedev "/dev/null"       # the raw device to be used (ftape only)
> changerfile "/etc/amanda/daily/changer"
> #changerfile "/etc/amanda/DailySet1/changer-status"
> changerdev "/dev/sg7"
> 
> maxdumpsize -1                # Maximum number of bytes the planner will 
> schedule
>                       # for a run (default: runtapes * tape_length).
> tapetype LTO2         # what kind of tape it is (see tapetypes below)
> labelstr "^[0-9][0-9][0-9][0-9][0-9][0-9]*$"  # label constraint regex: all 
> tapes must match
> 
> amrecover_do_fsf yes          # amrecover will call amrestore with the
>                               # -f flag for faster positioning of the tape.
> amrecover_check_label yes     # amrecover will call amrestore with the
>                               # -l flag to check the label.
> amrecover_changer "null:"     # amrecover will use the changer if you restore
>                               # from this device.
>                               # It could be a string like 'changer' and
>                               # amrecover will use your changer if you
>                               # set your tape with 'settape changer'
> 
> holdingdisk hd1 {
>     comment "main holding disk"
>     directory "/tmp/amandahld"        # where the holding disk is
>     use 20000 Mb              # how much space can we use on it
>                       # a non-positive value means:
>                       #        use all space but that value
>     chunksize 1Gb     # size of chunk if you want big dump to be
>                       # dumped on multiple files on holding disks
>                       #  N Kb/Mb/Gb split images in chunks of size N
>                       #             The maximum value should be
>                       #             (MAX_FILE_SIZE - 1Mb)
>                       #  0          same as INT_MAX bytes
>     }
> 
> autoflush no #
> 
> infofile "/etc/amanda/daily/curinfo"  # database DIRECTORY
> logdir   "/etc/amanda/daily"          # log directory
> indexdir "/etc/amanda/daily/index"    # index directory
> #tapelist "@CONFIG_DIR/DailySet1/tapelist"    # list of used tapes
> # tapelist is stored, by default, in the directory that contains amanda.conf
> 
> # tapetypes
> 
> define tapetype LTO2 {
>     comment "LTO2/Ultrium tapes"
>     length 208277 mbytes
>     filemark 1049 kbytes
>     speed 2339 kps
> }
> 
> # dumptypes
> 
> define dumptype global {
>     comment "Global definitions"
>     tape_splitsize 20000 mbytes
>     split_diskbuffer "/tmp/amandasplit/split"
>     index yes
>     holdingdisk yes
> }
> 
> define dumptype normal {
>     global
>     compress none
>     comment "Typical dump"
>     program "GNUTAR"
>     priority medium
>     strategy standard
> }
> 
> # network interfaces
> 
> define interface local {
>     comment "a local disk"
>     use 6000 kbps
> }
> 
> define interface le0 {
>     comment "100 Mbps ethernet"
>     use 4000 kbps
> }
> 
> I also have the mail that Amanda sent after the backup was done, if anyone 
> wants to see it.  Any help would be greatly appreciated :)
> 
> -Paul
> 
> 


-- 
Frank Smith                                      fsmith AT hoovers DOT com
Sr. Systems Administrator                       Voice: 512-374-4673
Hoover's Online                                   Fax: 512-374-4501