Bug 508338 - Improving performance relating to random i/o on ext3 filesystems
Summary: Improving performance relating to random i/o on ext3 filesystems
Keywords:
Status: CLOSED INSUFFICIENT_DATA
Alias: None
Product: Red Hat Enterprise Linux 5
Classification: Red Hat
Component: kernel
Version: 5.3
Hardware: x86_64
OS: Linux
low
medium
Target Milestone: rc
: ---
Assignee: Eric Sandeen
QA Contact: Red Hat Kernel QE team
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2009-06-26 16:27 UTC by don frederick
Modified: 2013-02-25 19:05 UTC (History)
2 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2013-02-25 19:05:56 UTC
Target Upstream Version:
Embargoed:


Attachments (Terms of Use)

Description don frederick 2009-06-26 16:27:18 UTC
User-Agent:       Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.10) Gecko/2009042320 Red Hat/3.0.10-1.el5 Firefox/3.0.10

The issue is slow access times for our 99% random block levelIO.  Each read requires reading in multiple inodes before the data block when inodes are not cached.  We can't seem to keep inodes in cache even with the vfs_cache_pressure=0 setting.  

These poor IO response times are noticeable in our application.  We ran the exact same test with the same SAN and a server with a different OS and filesystem and saw good IO response times. 

Reproducible: Always

Comment 1 Ondrej Vasik 2009-07-07 12:41:46 UTC
I guess that's something for kernel guys, not for basic system directory layout package. Reassigning.

Comment 2 Eric Sandeen 2009-08-18 13:38:50 UTC
Got a testcase for this or a more complete description?   Is this multiple random reads within a single file, or (sounds more likely) randomly reading files scattered around a filesystem?

Comment 3 Eric Sandeen 2013-02-25 19:05:56 UTC
No response to the question after 3.5 years, I guess it's not terribly critical.

Feel free to re-open w/ more info if needed.


Note You need to log in before you can comment on or make changes to this bug.