Bug 146772
| Summary: | RHEL 3.0 is a lot slower than RHEL 2.1 when accessing directories with lot of files | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 3 | Reporter: | Paolo Campegiani <p.campegiani> |
| Component: | kernel | Assignee: | Larry Woodman <lwoodman> |
| Status: | CLOSED WONTFIX | QA Contact: | Brian Brock <bbrock> |
| Severity: | low | Docs Contact: | |
| Priority: | medium | ||
| Version: | 3.0 | CC: | petrides, riel |
| Target Milestone: | --- | ||
| Target Release: | --- | ||
| Hardware: | i686 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2007-07-10 15:47:05 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
Hello, Paolo. I believe this problem has already been fixed in RHEL3 U4. Please retry this with the latest RHEL3 kernel (which is 2.4.21-27.0.2.EL) and let us know if the installation time is significantly reduced. Thanks in advance. -ernie Hello Ernie, I've installed 2.4.21-27.0.2.ELsmp and performed the two tests again: things are better, but RHEL 2.1 kernel is still faster: RHEL 3.0 with 2.4.21-27.0.2smp First test: 881 secs Second : 32 secs. RedHat 2.1 (2.4.9-27+glibc 2.1.3) First test : 645 secs Second: 28 secs. RedHat 3.0 (2.4.21-20+glibc 2.2) First test : 1175 secs Second: 36 secs. The only big difference in the system is that the RAID software is getting filled (but we still have near 50 GB of free space), in the first test (the 2.1) it was almost empty. I don't believe this can affects performances so heavily. |
From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.3) Gecko/20041020 Description of problem: We have a dual Xeon machine, 6 GB RAM, 5 U320 SCSI disks, software RAID-5. We are using it for "Oracle Applications" (ERP application). I've noticed this problem during the installation of the Oracle software: whilst it takes 3-4 hour to do the installation with RHEL 3.0, it takes 1 hour with RHEL 2.1 (we had to downgrade the operating systems for Oracle related issues, that do not affect this bug). During the installation, I've noted that almost time was spent in untarring (not gunzipping) the incredible number of very small files the Oracle Applications are made of, so I've decided to do some more tests. I wrote two small shell script (provided below): The first creates 100k files, each with a name of 12 random characters let's say "D1 D2 D12" then mkdir -p /oracle/D1/D2/D3 then touch /oracle/D1/D2/D3/D1 D2 D12 (being /oracle the mount point for the software RAID). The second creates 10k files, each with random name, in the same directory. These are the results: RedHat 2.1 (2.4.9-27+glibc 2.1.3) First test : 645 secs Second: 28 RedHat 3.0 (2.4.21-20+glibc 2.2) First test : 1175 secs Second: 36 First script #! /bin/sh MATRIX="01234567890ABCDEFGHIJKLMNOPQRSTUVZabcdefghijklmnopqrstuvz" LENGTH="12" BASEDIR="/oracle/tmp/" for i in `seq 1 100000`; do n=1 while [ "$n" -le "$LENGTH" ] do PASS="$PASS${MATRIX:$(($RANDOM%${#MATRIX})):1}" let n+=1 done D1=${PASS:0:1} D2=${PASS:1:1} D3=${PASS:2:1} mkdir -p $BASEDIR/$D1/$D2/$D3 touch $BASEDIR/$D1/$D2/$D3/$PASS PASS="" done Second script #! /bin/sh MATRIX="01234567890ABCDEFGHIJKLMNOPQRSTUVZabcdefghijklmnopqrstuvz" LENGTH="12" BASEDIR="/oracle/tmp/" for i in `seq 1 10000`; do n=1 while [ "$n" -le "$LENGTH" ] do PASS="$PASS${MATRIX:$(($RANDOM%${#MATRIX})):1}" let n+=1 done touch $BASEDIR$PASS PASS="" done Important note: I've also measured the performance of RAID-5 software when it comes to very big files (bonnie++), and RHEL 3.0 is more or less 30% faster than RHEL 2.1, so it seems to me something related to directory accessing. Version-Release number of selected component (if applicable): kernel 2.4.21-20 How reproducible: Always Steps to Reproduce: 1. Use the two provided scripts Actual Results: RHEL 3.0 is slower than RHEL 2.1 when manipulating high populated directories. Additional info: It could be related to bdflush tuning? I didn't tune nor touch it from the installation.