libvirt users - Aug 2013 - Re: Oracle RAC in libvirt+KVM environment

Il 22/08/2013 09:46, Timon Wang ha scritto:
> Thanks Nicholas.
> 
> I found that scsicmd can't pass all the scsi3_test but the result of
> sg_inq is the same as it in the host.
> 
> I am absolutely confused about this situation. Am I missed some
> information about it?
I am also confused.  You need to understand the limitations that the
clustering software is putting.

Can you also try using the megaraid sas controller ("lsisas1078" in
libvirt) instead of virtio-scsi?

Paolo

I don't know if lsisas1078 controller in qemu is not work property or
I did not configure it correct.
Sometimes I can see the lun which passed to the vm, sometimes not.

I have tried that controller before, and sometimes the vm will crash
because qemu process quit, but I did not get the detail logs about the
process quit.
I am wondering if lsisas1078 is still not stable or I did not config it right.

On Thu, Aug 22, 2013 at 5:02 PM, Paolo Bonzini <pbonzini@redhat.com>
wrote:
> Il 22/08/2013 09:46, Timon Wang ha scritto:
>> Thanks Nicholas.
>>
>> I found that scsicmd can't pass all the scsi3_test but the result
of
>> sg_inq is the same as it in the host.
>>
>> I am absolutely confused about this situation. Am I missed some
>> information about it?
>
> I am also confused.  You need to understand the limitations that the
> clustering software is putting.
>
> Can you also try using the megaraid sas controller ("lsisas1078"
in
> libvirt) instead of virtio-scsi?
>
> Paolo


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>> I found that scsicmd can't pass all the scsi3_test but the result
of
>> sg_inq is the same as it in the host.
>>
>> I am absolutely confused about this situation. Am I missed some
>> information about it?
I guess this is caused by the lack of capability.
Please check if enough capability was added to kvm process by the following 
steps. 

  1. Check the pid of kvm process.
     # ps -C qemu-system-x86_64 -o pid      5177
  2. Check the capability for the process.
     # getpcaps 5177
     Capabilities for `5177': = cap_sys_rawio+i

In my fedora19 environment, as seen in above, only cap_sys_rawio+i was added
with rawio='yes'. Even though, cap_sys_rawio+ep is required to
pass-through
SCSI Reservation from the guest. 

Note that I succeeded to pass-through SCSI Reservation with the following steps
in my environment, not a Windows guest though.

  1. Stop the guest.
  2. Add CAP_SYS_RAWIO(effective, permitted) to qemu-kvm.
     # setcap cap_sys_rawio=ep /usr/bin/qemu-system-x86_64
  3. Start the guest.

However, I don't think this is the right way to workaround it, because it 
gives cap_sys_rawio+ep to all the kvm processes executed from this binary.

I believe following patches, which are not merged yet, are trying to solve 
this problem in a different approach.
     - [PATCH v3 part2] Add per-device sysfs knob to enable unrestricted, 
      unprivileged SG_IO
      https://lkml.org/lkml/2013/5/23/294
    - [RFC PATCH 0/4] SG_IO filtering via sysfs and minimal whitelist
      https://lkml.org/lkml/2013/5/27/230


Any comments on this?


Masaki