[Bug 893450] Re: libvirt fails to start correctly because LVM is not ready

[Peter Petrakis]

The disk sector size and how it's managed really determine how well it will
perform under various access sizes. In your case remember, the disk sector
size is 4k, so we would hope that Linux is "doing the right thing" in coalescing
these 1k accesses into chunks which get the most out of your hard disks.

That's not our primary problem here, the primary problem here is LVM 
having trouble bringing all LVs online. These performance issues are
in addition to that. The LVM problem appears to have been addressed
by adding a root delay so that's that.

We have yet to pin down where any of them have come from. That this
problem appeared after an update is suspicious, yet iirc you've shown
that rolling kernels back and forth have no net impact on the symptoms.

If an update was really the root of all of this you should be able to
install natty to a separate set of disks, re-run these tests and see dramatically
different numbers for the 1K test runs.

We are now left with the actual configuration of your entire stack, the
loads generated by your VMs, and how they might be affecting your
IO subsystem.

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to udev in Ubuntu.
https://bugs.launchpad.net/bugs/893450

Title:
  libvirt fails to start correctly because LVM is not ready

Status in “libvirt” package in Ubuntu:
  Incomplete
Status in “udev” package in Ubuntu:
  Incomplete

Bug description:
  Some times, one of the KVM guest failed to start. I've 3 guest, two
  started OK and one failed (the two times the same has failed). After
  rebooting the host two times, the KVM guest started OK, but this is a
  server and found too risky this behavior. The host server is running
  "Ubuntu 11.04 Server 64bits" and libvirt 0.8.8-1ubuntu6.5

  The two times that failed, I've found this on syslog:

  error : virSecurityDACSetOwnership:125 : unable to set user and group to '105:115' on '/dev/vg_default/lv_robot-pv0': No such file or directory
  kernel: [  200.354543] type=1400 audit(1321932141.068:11): apparmor="DENIED" operation="open" parent=2539 profile="/usr/lib/libvirt/virt-aa-helper" name="/dev/dm-7" pid=2638 comm="virt-aa-helper" requested_mask="r" denied_mask="r" fsuid=0 ouid=105
  kernel: [  200.692255] type=1400 audit(1321932141.408:12): apparmor="STATUS" operation="profile_load" name="libvirt-7262201f-566b-d0b1-16ec-0b404ccd5336" pid=2639 comm="apparmor_parser"
  libvirtd: 00:22:21.424: 2539: error : virSecurityDACRestoreSecurityFileLabel:143 : cannot resolve symlink /dev/vg_default/lv_robot-pv0: No such file or directory
  libvirtd: 00:22:21.707: 2539: error : qemuAutostartDomain:275 : Failed to autostart VM 'robot': unable to set user and group to '105:115' on '/dev/vg_default/lv_robot-pv0': No such file or directory

  The LVM device is on a software raid. Maybe this is taking too long to
  come up?

  FYI, running "aa-status" (after the reboots) gives me:
  apparmor module is loaded.
  9 profiles are loaded.
  9 profiles are in enforce mode.
     /sbin/dhclient
     /usr/lib/NetworkManager/nm-dhcp-client.action
     /usr/lib/connman/scripts/dhclient-script
     /usr/lib/libvirt/virt-aa-helper
     /usr/sbin/libvirtd
     /usr/sbin/tcpdump
     libvirt-7262201f-566b-d0b1-16ec-0b404ccd5336
     libvirt-c032ea0a-8c62-7730-fb4d-e1bf60c15a31
     libvirt-f06ad419-f312-f002-444f-3e51f40d2291
  0 profiles are in complain mode.
  4 processes have profiles defined.
  4 processes are in enforce mode :
     /usr/sbin/libvirtd (2459) 
     libvirt-7262201f-566b-d0b1-16ec-0b404ccd5336 (2521) 
     libvirt-c032ea0a-8c62-7730-fb4d-e1bf60c15a31 (2551) 
     libvirt-f06ad419-f312-f002-444f-3e51f40d2291 (2582) 
  0 processes are in complain mode.
  0 processes are unconfined but have a profile defined.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/893450/+subscriptions