[Qemu-devel] Question about scsi emulation

[Qemu-devel] Question about scsi emulation

[Yaoli Zheng]

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Hi,

We have problem using qemu emulated scsi driver(the old lsi). Wonder if any of other device model we can try for emulating scsi, and how we can get and config it in Xen? Having been told virtio-scsi is alternative one, but have no idea how to get it work in Xen.

Thanks!

Yaoli Zheng

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Re: [Qemu-devel] Question about scsi emulation

[Stefan Hajnoczi]

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On Wed, Mar 18, 2015 at 02:16:47PM -0700, Yaoli Zheng wrote:
> We have problem using qemu emulated scsi driver(the old lsi). Wonder if any of other device model we can try for emulating scsi, and how we can get and config it in Xen? Having been told virtio-scsi is alternative one, but have no idea how to get it work in Xen.

The MegaSAS HBA might be another option.  Not sure whether MegaSAS or
virtio-scsi are supported under Xen though.

Stefan

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Re: [Qemu-devel] [Xen-devel] Question about scsi emulation

[Stefano Stabellini]

On Mon, 23 Mar 2015, Stefan Hajnoczi wrote:
> On Wed, Mar 18, 2015 at 02:16:47PM -0700, Yaoli Zheng wrote:
> > We have problem using qemu emulated scsi driver(the old lsi). Wonder if any of other device model we can try for emulating scsi, and how we can get and config it in Xen? Having been told virtio-scsi is alternative one, but have no idea how to get it work in Xen.
> 
> The MegaSAS HBA might be another option.  Not sure whether MegaSAS or
> virtio-scsi are supported under Xen though.
 
Making MegaSAS HBA work on Xen should be easy.

Rather than virtio-scsi I would consider the new Xen pvscsi
frontend/backend drivers, now upstream in Linux
(drivers/scsi/xen-scsifront.c and drivers/xen/xen-scsiback.c). Usually
Xen PV drivers perform much better than virtio devices on Xen.

That said, probably most things would be better than the old lsi.

Re: [Qemu-devel] [Xen-devel] Question about scsi emulation

[Yaoli Zheng]

Thank you for the advice!
It will be grateful if someone can provide any guide how to config  MegaSAS HBA or how to use xen pvscsi in XEN.
There seems no option in XEN for these two driver emulation and no document found online.

Thanks!

-----Original Message-----
From: Stefano Stabellini [mailto:stefano.stabellini@eu.citrix.com] 
Sent: Monday, March 23, 2015 11:18 AM
To: Stefan Hajnoczi
Cc: Yaoli Zheng; qemu-devel@nongnu.org; xen-devel@lists.xen.org
Subject: Re: [Xen-devel] [Qemu-devel] Question about scsi emulation

On Mon, 23 Mar 2015, Stefan Hajnoczi wrote:
> On Wed, Mar 18, 2015 at 02:16:47PM -0700, Yaoli Zheng wrote:
> > We have problem using qemu emulated scsi driver(the old lsi). Wonder if any of other device model we can try for emulating scsi, and how we can get and config it in Xen? Having been told virtio-scsi is alternative one, but have no idea how to get it work in Xen.
> 
> The MegaSAS HBA might be another option.  Not sure whether MegaSAS or 
> virtio-scsi are supported under Xen though.
 
Making MegaSAS HBA work on Xen should be easy.

Rather than virtio-scsi I would consider the new Xen pvscsi frontend/backend drivers, now upstream in Linux (drivers/scsi/xen-scsifront.c and drivers/xen/xen-scsiback.c). Usually Xen PV drivers perform much better than virtio devices on Xen.

That said, probably most things would be better than the old lsi.

Re: [Qemu-devel] [Xen-devel] Question about scsi emulation

[Juergen Gross]

On 03/24/2015 01:20 AM, Yaoli Zheng wrote:
> Thank you for the advice!
> It will be grateful if someone can provide any guide how to config  MegaSAS HBA or how to use xen pvscsi in XEN.
> There seems no option in XEN for these two driver emulation and no document found online.

The pvscsi driver is rather new in the Linux kernel. Support for pvscsi
in Xen tools (xl) is just being worked on:

http://lists.xen.org/archives/html/xen-devel/2015-03/msg00030.html

Juergen

>
> Thanks!
>
> -----Original Message-----
> From: Stefano Stabellini [mailto:stefano.stabellini@eu.citrix.com]
> Sent: Monday, March 23, 2015 11:18 AM
> To: Stefan Hajnoczi
> Cc: Yaoli Zheng; qemu-devel@nongnu.org; xen-devel@lists.xen.org
> Subject: Re: [Xen-devel] [Qemu-devel] Question about scsi emulation
>
> On Mon, 23 Mar 2015, Stefan Hajnoczi wrote:
>> On Wed, Mar 18, 2015 at 02:16:47PM -0700, Yaoli Zheng wrote:
>>> We have problem using qemu emulated scsi driver(the old lsi). Wonder if any of other device model we can try for emulating scsi, and how we can get and config it in Xen? Having been told virtio-scsi is alternative one, but have no idea how to get it work in Xen.
>>
>> The MegaSAS HBA might be another option.  Not sure whether MegaSAS or
>> virtio-scsi are supported under Xen though.
>
> Making MegaSAS HBA work on Xen should be easy.
>
> Rather than virtio-scsi I would consider the new Xen pvscsi frontend/backend drivers, now upstream in Linux (drivers/scsi/xen-scsifront.c and drivers/xen/xen-scsiback.c). Usually Xen PV drivers perform much better than virtio devices on Xen.
>
> That said, probably most things would be better than the old lsi.
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
>

Re: [Qemu-devel] [Xen-devel] Question about scsi emulation

[Stefano Stabellini]

On Tue, 24 Mar 2015, Juergen Gross wrote:
> On 03/24/2015 01:20 AM, Yaoli Zheng wrote:
> > Thank you for the advice!
> > It will be grateful if someone can provide any guide how to config  MegaSAS
> > HBA or how to use xen pvscsi in XEN.
> > There seems no option in XEN for these two driver emulation and no document
> > found online.
> 
> The pvscsi driver is rather new in the Linux kernel. Support for pvscsi
> in Xen tools (xl) is just being worked on:
> 
> http://lists.xen.org/archives/html/xen-devel/2015-03/msg00030.html
> 

Regarding MegaSAS, it should be just a matter of passing the right
command line arguments to QEMU so that it will emulate it, same as for
QEMU without Xen. You can use device_model_args in the VM config file to
pass custom command line arguments from xl to QEMU.


> > 
> > Thanks!
> > 
> > -----Original Message-----
> > From: Stefano Stabellini [mailto:stefano.stabellini@eu.citrix.com]
> > Sent: Monday, March 23, 2015 11:18 AM
> > To: Stefan Hajnoczi
> > Cc: Yaoli Zheng; qemu-devel@nongnu.org; xen-devel@lists.xen.org
> > Subject: Re: [Xen-devel] [Qemu-devel] Question about scsi emulation
> > 
> > On Mon, 23 Mar 2015, Stefan Hajnoczi wrote:
> > > On Wed, Mar 18, 2015 at 02:16:47PM -0700, Yaoli Zheng wrote:
> > > > We have problem using qemu emulated scsi driver(the old lsi). Wonder if
> > > > any of other device model we can try for emulating scsi, and how we can
> > > > get and config it in Xen? Having been told virtio-scsi is alternative
> > > > one, but have no idea how to get it work in Xen.
> > > 
> > > The MegaSAS HBA might be another option.  Not sure whether MegaSAS or
> > > virtio-scsi are supported under Xen though.
> > 
> > Making MegaSAS HBA work on Xen should be easy.
> > 
> > Rather than virtio-scsi I would consider the new Xen pvscsi frontend/backend
> > drivers, now upstream in Linux (drivers/scsi/xen-scsifront.c and
> > drivers/xen/xen-scsiback.c). Usually Xen PV drivers perform much better than
> > virtio devices on Xen.
> > 
> > That said, probably most things would be better than the old lsi.
> > 
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@lists.xen.org
> > http://lists.xen.org/xen-devel
> > 
>