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Bug 481226

Summary: Bitmap Merging Patch for RHEL 5.4
Product: Red Hat Enterprise Linux 5 Reporter: Tomen Tse <ttse>
Component: kernelAssignee: Doug Ledford <dledford>
Status: CLOSED ERRATA QA Contact: Red Hat Kernel QE team <kernel-qe>
Severity: medium Docs Contact:
Priority: high    
Version: 5.3CC: cward, dzickus, kzhang, paul.clements, sghosh
Target Milestone: rcKeywords: FutureFeature, OtherQA
Target Release: 5.4   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Enhancement
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2009-09-02 08:21:18 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:
Bug Depends On:    
Bug Blocks: 483701    
Attachments:
Description Flags
patch file none

Description Tomen Tse 2009-01-22 21:16:37 UTC
Description of problem:
FutureFeature

Version-Release number of selected component (if applicable):
RHEL 5.4

One of our ISV partners in the backup and recovery space, Steeleye, was wondering if we can apply the bitmap merging patch to the next dot release of EL. According to their email, the patch is available in kernel 2.6.19. Since RHEL 5 is based on 2.6.18, it is not currently included in our distribution. Please let me know if this is something you would consider for RHEL 5.4 or later.

********
Steeleye's email:
Since it looks like RHEL 6 is approx. one year away, it seems likely you will do another dot release of RHEL 5 before that happens. I wonder if you would consider making an addition to that dot release that might be a big help to both of our companies.

As you may know we have a very fine data replication product in SteelEye Data Replication, and it is selling very well. And a large percentage of our sales of that product are on Red Hat. We have a very important enhancement to that product coming out in this quarter that will virtually eliminate all full resyncs when doing replication. This is a feature we call bitmap merging, and it is facilitated by a change in the kernel that occurred in 2.6.19. As you know, Red Hat EL 5 is based on 2.6.18, so we just missed it. But in the not so distant future another major Linux distro will come out based on a 2.6.27 kernel, and we will be able to support bitmap merging with this distro. The next release of SteelEye Data Replication will support bitmap merging / resync elimination on kernels that have that support built in; version numbers don’t matter.

In hopes of keeping the playing field level, would you folks consider applying the bitmap merging patch to the next dot release of EL 5? It’s a really small patch, maybe a page in length. We have successfully applied the patch to 5.2 and it seems to work just fine. And it is already in the upstream kernel, so the risks would really small in doing this. We would really like to be able eliminate full resyncs on Red Hat EL, and not have to wait for EL 6. As long as the kernel hook is there we should be able to support the feature just fine on Red Hat EL 5. 
********

Comment 1 Paul Clements 2009-01-22 22:27:40 UTC
Created attachment 329745 [details]
patch file

This patch enables a simple sysfs interface that allows the bitmap of a running md array to be modified.

Comment 2 Jens Petersen 2009-01-22 23:42:51 UTC
Moving to right component.

Comment 6 RHEL Program Management 2009-02-16 15:22:00 UTC
Updating PM score.

Comment 8 Don Zickus 2009-05-12 17:41:03 UTC
in kernel-2.6.18-146.el5
You can download this test kernel from http://people.redhat.com/dzickus/el5

Please do NOT transition this bugzilla state to VERIFIED until our QE team
has sent specific instructions indicating when to do so.  However feel free
to provide a comment indicating that this fix has been verified.

Comment 10 Zhang Kexin 2009-07-28 05:14:23 UTC
Hi Paul,

would you test this feature for us? this patch get in kernel 2.6.18-145.
if you would like to test, I'll supply the kernel package. thanks.

Comment 11 Zhang Kexin 2009-07-28 05:19:09 UTC
Hi Paul,

You can download the test kernel from http://people.redhat.com/dzickus/el5

please use the newest kernel. thanks.

Comment 12 Paul Clements 2009-07-28 15:48:09 UTC
I have tested the patch and everything works correctly. I tested against kernel version kernel-2.6.18-146.el5.

Comment 13 Zhang Kexin 2009-07-29 06:39:29 UTC
verified by partner, we just do code review, patch is in. add SanityOnly.

Comment 14 Chris Ward 2009-08-03 15:46:02 UTC
~~ Attention Partners - RHEL 5.4 Snapshot 5 Released! ~~

RHEL 5.4 Snapshot 5 is the FINAL snapshot to be release before RC. It has been 
released on partners.redhat.com. If you have already reported your test results, 
you can safely ignore this request. Otherwise, please notice that there should be 
a fix available now that addresses this particular issue. Please test and report 
back your results here, at your earliest convenience.

If you encounter any issues while testing Beta, please describe the 
issues you have encountered and set the bug into NEED_INFO. If you 
encounter new issues, please clone this bug to open a new issue and 
request it be reviewed for inclusion in RHEL 5.4 or a later update, if it 
is not of urgent severity. If it is urgent, escalate the issue to your partner manager as soon as possible. There is /very/ little time left to get additional code into 5.4 before GA.

Partners, after you have verified, do not flip the bug status to VERIFIED. Instead, please set your Partner ID in the Verified field above if you have successfully verified the resolution of this issue. 

Further questions can be directed to your Red Hat Partner Manager or other 
appropriate customer representative.

Comment 16 errata-xmlrpc 2009-09-02 08:21:18 UTC
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2009-1243.html