Amanda-Users

Questions about bumpsize, frustration

2002-08-23 13:48:02
Subject: Questions about bumpsize, frustration
From: "Brashers, Bart -- MFG, Inc." <Bart.Brashers AT mfgenv DOT com>
To: "Amanda Users (E-mail)" <amanda-users AT amanda DOT org>
Date: Fri, 23 Aug 2002 11:28:16 -0600
Hi everyone,

I have disks that get dumped far too often.  From amoverview:

     date                   08 08 08 08 08 08 08 08 08 08 08 08 08 08 08
host disk                   08 09 10 11 12 13 14 15 16 17 18 19 20 21 22
beow /home/proj/bp-9725      0  1        1  1  2  3  4           4  4  0

Looks ok to me, so far.  But if I go back and look at the email reports for
this disk:

                                DUMPER STATS               TAPER STATS  
HOST  DISK        L  ORIG-KB   OUT-KB COMP% MMM:SS   KB/s MMM:SS    KB/s
------------------- ------------------------------------- --------------
beow  -oj/bp-9725 0 15377888 15377888   --   17:2814670.5  43:32  5886.4
8/8
beow  -oj/bp-9725 1 15378464 15378464   --   17:3614558.2  43:49  5850.5
8/9
beow  -oj/bp-9725 1 15378464 15378464   --   17:1414874.1  43:40  5870.0
8/12
beow  -oj/bp-9725 2 15379040 15379040   --   54:31 4701.8   N/A     N/A
8/14
beow  -oj/bp-9725 2      N/A 15379072   --    N/A    N/A   48:40  5267.0
8/14
beow  -oj/bp-9725 3 15382368 15382368   --   35:54 7141.2  65:48  3895.9
8/15
beow  -oj/bp-9725 4 15382368 15382368   --   18:4213715.6  FAILED  ------
8/16
beow  -oj/bp-9725 4 FAILED ---------------------------------------------
8/19
beow  -oj/bp-9725 4 15382464 15382464   --   19:3613084.4  43:46  5858.5  8
20
beow  -oj/bp-9725 4 15382464 15382464   --   19:5712852.9  58:40  4370.0
8/21
beow  -oj/bp-9725 0 15477440 15477440   --   18:1614120.4  57:27  4489.8
8/22

It looks like it's getting a full dump just about every time.  The files are
changing, slightly.  I did a "du -csh `find /home/proj/bp-9725 -mtime N`"
for the last N days:

N  Date  Size changed on disk
-- ----  --------------------
14 8/8   0
13 8/9   3.2M
10 8/12  0
8  8/14  94M
7  8/15  3.3M
6  8/16  0
3  8/19  0
2  8/20  20k
1  8/21  0
0  8/22  680M

So for example, the level 1 dump on 8/9 should have found 3.2M of new files
to dump, yet it dumped 15G!  The period 8/13 -> 8/16 had some days with no
changes, some days with small (3.3M) changes, and one day with 94M of
changed files.  Yet it did a full dump each time.

Could this be related to the default setting in amanda.conf:

bumpsize 20 Mb          # minimum savings (threshold) to bump level 1 -> 2
bumpdays 1              # minimum days at each level
bumpmult 2              # threshold = bumpsize * bumpmult^(level-1)

For reference, the important parts of my amanda.conf:

dumpcycle 2 weeks, runspercycle 10, tapecycle 22 tapes
runtapes 2, tpchanger "chg-manual", tapetype DLT8000-hwcomp
holdingdisk hd1 {use 40 Gb, chunksize 1 Gb }
reserve 30 # percent
About 185G total to backup.

Any other suggestions as to how to track down this problem would be greatly
appreciated.  I'm almost getting to the point where I'm going to abandon
amanda and find some other backup software.  It's really frustrating to
_never_ read an amreport email without 5 pages of FAILUREs.

Bart
---
Bart Brashers                           MFG Inc.
Air Quality Meteorologist               19203 36th Ave W Suite 101
bart.brashers AT mfgenv DOT com            Lynnwood WA 98036-5707
http://www.mfgenv.com                   425.921.4000 Fax: 425.921.4040

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