Update: Any clues why df shows wrong and floating info?

2012/6/28 Rafał Radecki radecki.rafal@gmail.com:

Hi all.

I have currently a server: cat /etc/redhat-release CentOS release 5.7 (Final) uname -a Linux host.domain.com 2.6.18-274.18.1.el5 #1 SMP Thu Feb 9 12:45:44 EST 2012 x86_64 x86_64 x86_64 GNU/Linux I have there a filesystem mounted:

/dev/vg0/paczki              /home/paczki-workdir  ext4 defaults,noatime           0 0

on which df  gives strange output:

LANG=C df -h /home/paczki-workdir;sleep 3;df -h /home/paczki-workdir Filesystem            Size  Used Avail Use% Mounted on /dev/mapper/vg0-paczki                     1008G  268G  690G  28% /home/paczki-workdir System plików         rozm. użyte dost. %uż. zamont. na /dev/mapper/vg0-paczki                     1008G  155G  803G  17% /home/paczki-workdir

du -sk /home/paczki-workdir;sleep 3;du -sk /home/paczki-workdir 48426364        /home/paczki-workdir 48428980        /home/paczki-workdir

du -sh /home/paczki-workdir;sleep 3;du -sh /home/paczki-workdir 47G     /home/paczki-workdir 47G     /home/paczki-workdir

Currently there is only one process writing to the filesystem:

root     27945 27918  3 09:16 ?        00:01:44 tar --exclude=*/Maildir/.Spam/cur/* --exclude=*/Maildir/.Spam/new/* --use-compress-program /usr/bin/pigz -cf /home/paczki-workdir/abaksa-mail-20120628-0413.tgz

and it writes so much data:

du -sh /home/paczki-workdir/abaksa-mail-20120628-0413.tgz;sleep 3;du -sh /home/paczki-workdir/abaksa-mail-20120628-0413.tgz 13G     /home/paczki-workdir/abaksa-mail-20120628-0413.tgz 13G     /home/paczki-workdir/abaksa-mail-20120628-0413.tgz

du -sk /home/paczki-workdir/abaksa-mail-20120628-0413.tgz;sleep 3;du -sk /home/paczki-workdir/abaksa-mail-20120628-0413.tgz 13410988        /home/paczki-workdir/abaksa-mail-20120628-0413.tgz 13425040        /home/paczki-workdir/abaksa-mail-20120628-0413.tgz

I've also noticed that when nothing writes to this filesystem than df output also varies over short time periods. When I've updated the kernel and restarted the host for few hours df was showing ok info. There is no info about problems in /var/log/messages and dmesg.

Additional info:

vgdisplay -v vg0    Using volume group(s) on command line    Finding volume group "vg0"  --- Volume group ---  VG Name               vg0  System ID  Format                lvm2  Metadata Areas        1  Metadata Sequence No  7  VG Access             read/write  VG Status             resizable  MAX LV                0  Cur LV                2  Open LV               2  Max PV                0  Cur PV                1  Act PV                1  VG Size               3,64 TB  PE Size               4,00 MB  Total PE              953863  Alloc PE / Size       786432 / 3,00 TB  Free  PE / Size       167431 / 654,03 GB  VG UUID               wRjDqu-TUlW-7YH2-j6xl-nuc1-EczW-D2CAOK

--- Logical volume ---  LV Name                /dev/vg0/paczki  VG Name                vg0  LV UUID                0EyRjA-p90A-bfX6-1zEA-eMba-5Hn5-jc9slo  LV Write Access        read/write  LV Status              available  # open                 1  LV Size                1,00 TB  Current LE             262144  Segments               1  Allocation             inherit  Read ahead sectors     auto  - currently set to     512  Block device           253:0

--- Logical volume ---  LV Name                /dev/vg0/msklon5  VG Name                vg0  LV UUID                8nlU4T-Qozl-bPnr-JOmh-g9Pi-cabs-J7yI7V  LV Write Access        read/write  LV Status              available  # open                 1  LV Size                2,00 TB  Current LE             524288  Segments               1  Allocation             inherit  Read ahead sectors     auto  - currently set to     512  Block device           253:1

--- Physical volumes ---  PV Name               /dev/md0  PV UUID               hly53e-wbbR-5xLo-3P4k-U4xt-8XeR-W0YCul  PV Status             allocatable  Total PE / Free PE    953863 / 167431

mdadm --detail /dev/md0 /dev/md0:        Version : 0.90  Creation Time : Wed Apr 11 10:37:04 2012     Raid Level : raid10     Array Size : 3907023872 (3726.03 GiB 4000.79 GB)  Used Dev Size : 1953511936 (1863.01 GiB 2000.40 GB)   Raid Devices : 4  Total Devices : 4 Preferred Minor : 0    Persistence : Superblock is persistent

Update Time : Thu Jun 28 10:17:04 2012          State : active  Active Devices : 4 Working Devices : 4  Failed Devices : 0  Spare Devices : 0

Layout : near=2     Chunk Size : 64K

UUID : 423fd5cf:beedc018:915808f0:8ec673de         Events : 0.845339

Number   Major   Minor   RaidDevice State       0       8       17        0      active sync   /dev/sdb1       1       8       33        1      active sync   /dev/sdc1       2       8       49        2      active sync   /dev/sdd1       3       8       65        3      active sync   /dev/sde1

Any clues why du shows wrong and floating info?

Best regards, Rafal Radecki.

Hello Rafal,

On Thu, 2012-06-28 at 10:25 +0200, Rafał Radecki wrote:

Currently there is only one process writing to the filesystem:

root 27945 27918 3 09:16 ? 00:01:44 tar --exclude=*/Maildir/.Spam/cur/* --exclude=*/Maildir/.Spam/new/* --use-compress-program /usr/bin/pigz -cf /home/paczki-workdir/abaksa-mail-20120628-0413.tgz

I don't see a path in that command. What is piping into tar?

du -sk /home/paczki-workdir/abaksa-mail-20120628-0413.tgz;sleep 3;du -sk /home/paczki-workdir/abaksa-mail-20120628-0413.tgz 13410988 /home/paczki-workdir/abaksa-mail-20120628-0413.tgz 13425040 /home/paczki-workdir/abaksa-mail-20120628-0413.tgz

So the above process is writing to that tarball and it increases in size over time. Guess the programme piping into tar is still producing data.

Regards, Leonard.