[ovirt-users] One RHEV Virtual Machine does not Automatically Resume following Compellent SAN Controller Failover

[Roy Golan]

On Mon, Nov 23, 2015 at 9:37 PM, Duckworth, Douglas C <duckd at tulane.edu>
wrote:

> Hello --
>
> Not sure if y'all can help with this issue we've been seeing with RHEV...
>
> On 11/13/2015, during Code Upgrade of Compellent SAN at our Disaster
> Recovery Site, we Failed Over to Secondary SAN Controller.  Most Virtual
> Machines in our DR Cluster Resumed automatically after Pausing except VM
> "BADVM" on Host "BADHOST."
>
> In Engine.log you can see that BADVM was sent into "VM_PAUSED_EIO" state
> at 10:47:57:
>
> "VM BADVM has paused due to storage I/O problem."
>
> On this Red Hat Enterprise Virtualization Hypervisor 6.6
> (20150512.0.el6ev) Host, two other VMs paused but then automatically
> resumed without System Administrator intervention...
>
> In our DR Cluster, 22 VMs also resumed automatically...
>
> None of these Guest VMs are engaged in high I/O as these are DR site VMs
> not currently doing anything.
>
> We sent this information to Dell.  Their response:
>
> "The root cause may reside within your virtualization solution, not the
> parent OS (RHEV-Hypervisor disc) or Storage (Dell Compellent.)"
>
> We are doing this Failover again on Sunday November 29th so we would
> like to know how to mitigate this issue, given we have to manually
> resume paused VMs that don't resume automatically.
>
> Before we initiated SAN Controller Failover, all iSCSI paths to Targets
> were present on Host tulhv2p03.
>
> VM logs on Host show in /var/log/libvirt/qemu/badhost.log that Storage
> error was reported:
>
> block I/O error in device 'drive-virtio-disk0': Input/output error (5)
> block I/O error in device 'drive-virtio-disk0': Input/output error (5)
> block I/O error in device 'drive-virtio-disk0': Input/output error (5)
> block I/O error in device 'drive-virtio-disk0': Input/output error (5)
>
> All disks used by this Guest VM are provided by single Storage Domain
> COM_3TB4_DR with serial "270."  In syslog we do see that all paths for
> that Storage Domain Failed:
>
> Nov 13 16:47:40 multipathd: 36000d310005caf000000000000000270: remaining
> active paths: 0
>
> Though these recovered later:
>
> Nov 13 16:59:17 multipathd: 36000d310005caf000000000000000270: sdbg -
> tur checker reports path is up
> Nov 13 16:59:17 multipathd: 36000d310005caf000000000000000270: remaining
> active paths: 8
>
> Does anyone have an idea of why the VM would fail to automatically
> resume if the iSCSI paths used by its Storage Domain recovered?
>

Look at the vdsm.log for events which libvirt emits and the actions that
vdsm takes on them. One of the actions would be to unpause the VM AFAIR. If
you didn't see this then QEMU/libvirt failed to propagatate the new state
change or it might be deeper down the stack. If there are events there then
share the vdsm logs.


>
> Thanks
> Doug
>
> --
> Thanks
>
> Douglas Charles Duckworth
> Unix Administrator
> Tulane University
> Technology Services
> 1555 Poydras Ave
> NOLA -- 70112
>
> E: duckd at tulane.edu
> O: 504-988-9341
> F: 504-988-8505
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> Users mailing list
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> http://lists.ovirt.org/mailman/listinfo/users
>
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