kdmflush and kjournald2 with high IOwait

Filipe Carvalho filipe.f.carvalho at gmail.com
Thu Dec 10 12:29:11 UTC 2009


    Hi,

    Last weekend I've add a new hard drive and done a fresh installation
fedora 12 on it.

    Now, sometimes when I'm using mainly firefox, thunderbird or yum in
gnome-panel it shows almost 50% iowait (and sometimes 100%, depending if
are using one or two cores) after do some action, for example, moving
some messages between folders or view a new web page in firefox or
installing some software with yum...

12:20:30 PM     CPU     %user     %nice   %system   %iowait   
%steal     %idle
12:20:35 PM     all      7.94      0.00      4.46     40.28     
0.00     47.32
12:20:40 PM     all     18.63      0.00     17.83     24.20     
0.00     39.34
12:20:45 PM     all     10.31      0.00      7.73     44.80     
0.00     37.17
12:20:50 PM     all      5.25      0.00      1.19     45.49     
0.00     48.07
12:20:55 PM     all      4.45      0.00      1.09     41.70     
0.00     52.77
12:21:00 PM     all      5.05      0.00      1.49      0.00     
0.00     93.47
12:21:05 PM     all      4.86      0.00      1.09      0.00     
0.00     94.05

    During some time (one or two minutes) the computer stays unusable.
During this time with iotop, every two seconds kdmflush and kjournald2
appear with 99% in IO column, and nothing relevant about the application
I'm using.

    I've done some tests with dd to crate one large and hundreds small
files in the disk and this doesn't happens.

    At this point I don't know if the problem is on the disk or some bug
in fedora.

    Can you tell something how to debug this problem?

    Now I write some information about the disk.

-- begin --
[root at AbsolutCitronela ~]# smartctl -i /dev/sdb
smartctl version 5.38 [x86_64-redhat-linux-gnu] Copyright (C) 2002-8
Bruce Allen
Home page is http://smartmontools.sourceforge.net/

=== START OF INFORMATION SECTION ===
Device Model:     WDC WD10EADS-00P8B0
Serial Number:    WD-WCAVU0108589
Firmware Version: 01.00A01
User Capacity:    1,000,204,886,016 bytes
Device is:        Not in smartctl database [for details use: -P showall]
ATA Version is:   8
ATA Standard is:  Exact ATA specification draft version not indicated
Local Time is:    Thu Dec 10 12:27:21 2009 WET
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

[root at AbsolutCitronela ~]# hdparm -i /dev/sdb

/dev/sdb:

 Model=WDC, FwRev=01.00A01, SerialNo=WD-WCAVU0108589
 Config={ HardSect NotMFM HdSw>15uSec SpinMotCtl Fixed DTR>5Mbs FmtGapReq }
 RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=50
 BuffType=unknown, BuffSize=unknown, MaxMultSect=16, MultSect=8
 CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=1953525168
 IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
 PIO modes:  pio0 pio3 pio4
 DMA modes:  mdma0 mdma1 mdma2
 UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6
 AdvancedPM=no WriteCache=enabled
 Drive conforms to: Unspecified:  ATA/ATAPI-1,2,3,4,5,6,7

 * signifies the current active mode

--  end --

    The SATA controller is an ICH6R.

00:1f.2 SATA controller: Intel Corporation 82801FR/FRW (ICH6R/ICH6RW)
SATA Controller (rev 03)


    Thanks in advance.

    Regards,
   
    Filipe


   

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