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Bug 175140 - Ext3 strange state during heavy writes
Summary: Ext3 strange state during heavy writes
Status: CLOSED DUPLICATE of bug 156437
Alias: None
Product: Red Hat Enterprise Linux 4
Classification: Red Hat
Component: kernel
Version: 4.0
Hardware: i386
OS: Linux
Target Milestone: ---
: ---
Assignee: Stephen Tweedie
QA Contact: Brian Brock
Depends On:
TreeView+ depends on / blocked
Reported: 2005-12-06 22:08 UTC by drew.middlesworth
Modified: 2007-11-30 22:07 UTC (History)
2 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2005-12-07 12:38:47 UTC
Target Upstream Version:

Attachments (Terms of Use)
Program to create slow writes state (deleted)
2005-12-06 22:09 UTC, drew.middlesworth
no flags Details

Description drew.middlesworth 2005-12-06 22:08:02 UTC
From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20050922 CentOS/1.7.12-1.4.1.centos4

Description of problem:
During writes to an ext3 filesystem after an amount of time the writes will slow almost to a halt with a kernel process eating up an entire cpu (25% of system time on a HT dual system). Stopping the process and starting it again fixes it for some time. Switching the filesystem to ext2 or running the latest from ( fixes this issue completely. We have created a program to duplicate this issue which I will attach, and seems to happen after about 40Gig has been written. This is on kernel-smp-2.6.9-22.0.1.EL.


avg-cpu:  %user   %nice    %sys %iowait   %idle
          0.10    0.00   25.04    0.60   74.26

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               1.80         0.00       682.40          0       3412
sdb               0.00         0.00         0.00          0          0


top - 17:50:23 up 51 min,  4 users,  load average: 1.12, 4.49, 7.78
Tasks:  79 total,   2 running,  77 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.0% us, 25.1% sy,  0.0% ni, 73.8% id,  1.1% wa,  0.0% hi,  0.0% si
Mem:   4148928k total,  4132900k used,    16028k free,    16368k buffers
Swap:  8193108k total,      128k used,  8192980k free,  3998196k cached

3073 root      25   0  1888  428  360 R 99.9  0.0  13:00.88  make-fragmentat    
222 root      15   0     0    0    0 S  0.3  0.0   0:50.89 kjournald         

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:
1. compile program make-fragmentation.c
2. run program make-fragmentation
3. iostat will show the writes slowing to almost nothing

Actual Results:  The process's writes would slow to about 600KB/s and system time would stick at 25% (1 of 4 virtual HT processors)

Expected Results:  System writes should have remained at a ~40MB/s level

Additional info:

Comment 1 drew.middlesworth 2005-12-06 22:09:03 UTC
Created attachment 121947 [details]
Program to create slow writes state

Comment 3 Stephen Tweedie 2005-12-07 12:38:47 UTC
Fixed in 2.6.9-22.12; will be in U3.

*** This bug has been marked as a duplicate of 156437 ***

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