Re: [Qemu-devel] [PATCH v7 RFC] block/vxhs: Initial commit to add Veritas HyperScale VxHS block device support

[Paolo Bonzini]

On 25/10/2016 07:07, Ketan Nilangekar wrote:
> We are able to derive significant performance from the qemu block
> driver as compared to nbd/iscsi/nfs. We have prototyped nfs and nbd
> based io tap in the past and the performance of qemu block driver is
> significantly better. Hence we would like to go with the vxhs driver
> for now.

Is this still true with failover implemented outside QEMU (which
requires I/O to be proxied, if I'm not mistaken)?  What does the benefit
come from if so, is it the threaded backend and performing multiple
connections to the same server?

Paolo

> Ketan
> 
> 
>> On Oct 24, 2016, at 4:24 PM, Paolo Bonzini <address@hidden>
>> wrote:
>> 
>> 
>> 
>>> On 20/10/2016 03:31, Ketan Nilangekar wrote: This way the
>>> failover logic will be completely out of qemu address space. We
>>> are considering use of some of our proprietary 
>>> clustering/monitoring services to implement service failover.
>> 
>> Are you implementing a different protocol just for the sake of
>> QEMU, in other words, and forwarding from that protocol to your
>> proprietary code?
>> 
>> If that is what you are doing, you don't need at all a vxhs driver
>> in QEMU.  Just implement NBD or iSCSI on your side, QEMU already
>> has drivers for that.
>> 
>> Paolo