Bug 684786
| Summary: | cache, aio defaults not applied to disks added via 'add hardware' | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 6 | Reporter: | Cole Robinson <crobinso> |
| Component: | python-virtinst | Assignee: | Cole Robinson <crobinso> |
| Status: | CLOSED ERRATA | QA Contact: | Virtualization Bugs <virt-bugs> |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | 6.1 | CC: | dyuan, hjiang, mzhan, rwu, troels |
| Target Milestone: | rc | ||
| Target Release: | --- | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: |
Cause:
Optimal cache and aio defaults were only applied at guest creation time, but not to disk devices added to an existing guest.
Consequence:
Disk performance was sub optimal for disks added to existing guests.
Fix:
Make sure optimal defaults are applied to new disks for existing guests.
Result:
Better performance!
|
Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | 2011-12-06 16:15:49 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: | |||
|
Description
Cole Robinson
2011-03-14 13:51:48 UTC
Since RHEL 6.1 External Beta has begun, and this bug remains unresolved, it has been rejected as it is not proposed as exception or blocker. Red Hat invites you to ask your support representative to propose this request, if appropriate and relevant, in the next release of Red Hat Enterprise Linux. As much as I'd like to get this in, it could possibly cause regressions, so deferring to 6.2 Fixed upstream in virtinst with a build time switch for rhel6 defaults: http://git.fedorahosted.org/git?p=python-virtinst.git;a=commit;h=0075dd8730adaf8aa3d7f90655d0626374fdd5b4 Fixed in python-virtinst-0.600.0-1.el6 verified with the following components:
rplibvirt-0.9.4-0rc1.2.el6.x86_64
qemu-kvm-0.12.1.2-2.175.el6.x86_64
python-virtinst-0.600.0-2.el6.noarch
kernel-2.6.32-171.el6.x86_64
Steps:
# virt-install -n test -r 512 --disk path=/var/lib/libvirt/images/test.img,cache=none,io=threads --disk path=/dev/sda1 -c /home/en_windows_xp_professional_x64.iso --vnc
#virsh dumpxml test
...
<disk type='file' device='disk'>
<driver name='qemu' type='raw' cache='none' io='threads'/>
<source file='/var/lib/libvirt/images/test.img'/>
<target dev='hda' bus='ide'/>
<alias name='ide0-0-0'/>
<address type='drive' controller='0' bus='0' unit='0'/>
</disk>
<disk type='block' device='disk'>
<driver name='qemu' type='raw' cache='none' io='native'/>
<source dev='/dev/sda1'/>
<target dev='hdb' bus='ide'/>
<alias name='ide0-0-1'/>
<address type='drive' controller='0' bus='0' unit='1'/>
</disk>
<disk type='file' device='cdrom'>
<driver name='qemu' type='raw'/>
<source file='/home/en_windows_xp_professional_x64.iso'/>
<target dev='hdc' bus='ide'/>
<readonly/>
<alias name='ide0-1-0'/>
<address type='drive' controller='0' bus='1' unit='0'/>
</disk>
...
Additional info: Reference to Bug 690750, and Bug 722938
Technical note added. If any revisions are required, please edit the "Technical Notes" field
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New Contents:
Cause:
Optimal cache and aio defaults were only applied at guest creation time, but not to disk devices added to an existing guest.
Consequence:
Disk performance was sub optimal for disks added to existing guests.
Fix:
Make sure optimal defaults are applied to new disks for existing guests.
Result:
Better performance!
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-2011-1643.html |