Bug 734039

Summary:	include the latest libblkid in dump
Product:	Red Hat Enterprise Linux 5	Reporter:	Cedric Buissart <cbuissar>
Component:	dump	Assignee:	Adam Tkac <atkac>
Status:	CLOSED ERRATA	QA Contact:	Dalibor Pospíšil <dapospis>
Severity:	high	Docs Contact:
Priority:	medium
Version:	5.8	CC:	dapospis, ovasik, pkovar
Target Milestone:	rc	Keywords:	OtherQA
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:	Previously, dump was linked against the libblkid library, which processed many device-mapper devices inefficiently. With this update, dump has been rebuilt against an updated version of the libblkid library, and it is now able to process many device-mapper devices efficiently.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2011-11-29 16:21:03 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:

Description Cedric Buissart 2011-08-29 09:50:10 UTC

>> Description of problem:

libblkid has recently been patch to improve performance when facing a lot of device-mapper devices :
bz672985 - blkid runs very slow with many dm devices and a large blkid.tab file

Without this patch, blkid loops on ioctl'ing device-mapper for hours.


Dump has static compilation against liblkid library. 
Extract of compiling dump from source RPM :
[...]
checking for blkid/blkid.h... yes
checking for blkid_get_devname in -lblkid... yes
[...]
gcc -static -o dump [...] -lblkid [...]
[...]

It should simply be recompiled to get the patched library.


=> With a simple recompilation of the dump RPM with the current libblkid (e2fsprogs), we have gone from 33 minutes down to 9 seconds for dumping a small file.


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

any

>> How reproducible:

100%, but you need a proper environment to reproduce the issue (apparently : boot on SAN with many multipath is the most affected).

>> Steps to Reproduce:
1. get a boot on SAN machine, with ~100 multipath devices
2. dump
3. wait
  
>> Actual results:

wait, again and again. stracing, you will see a huge number of ioctl to device-mapper.

>> Expected results:

faster dumping

>> Additional info:
:-)

Comment 8 Petr Kovar 2011-10-05 13:17:56 UTC

    Technical note added. If any revisions are required, please edit the "Technical Notes" field
    accordingly. All revisions will be proofread by the Engineering Content Services team.
    
    New Contents:
Previously, dump was linked against the libblkid library, which processed many device-mapper devices inefficiently. With this update, dump has been rebuilt against an updated version of the libblkid library, and it is now able to process many device-mapper devices efficiently.

Comment 13 errata-xmlrpc 2011-11-29 16:21:03 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHBA-2011-1502.html