Re: qemu-img convert vs writing another copy tool

2020-01-24 Thread Richard W.M. Jones
On Fri, Jan 24, 2020 at 09:55:55AM +, Richard W.M. Jones wrote: > On Thu, Jan 23, 2020 at 01:21:28PM -0600, Eric Blake wrote: > > Could we also teach this to parse 'qemu-img map --output=json' > > format? And/or add 'qemu-img map --output=XYZ' (different from the > > current --output=human') th

Re: qemu-img convert vs writing another copy tool

2020-01-24 Thread Richard W.M. Jones
On Thu, Jan 23, 2020 at 01:21:28PM -0600, Eric Blake wrote: > On 1/23/20 12:35 PM, Richard W.M. Jones wrote: > > - Hint that the target already contains zeroes. It's almost always > >the case that we know this, but we cannot tell qemu. This was the > >cause of a big performance regressio

Re: qemu-img convert vs writing another copy tool

2020-01-23 Thread Markus Armbruster
"Richard W.M. Jones" writes: > On Thu, Jan 23, 2020 at 07:53:57PM +0100, Max Reitz wrote: >> On 23.01.20 19:35, Richard W.M. Jones wrote: >> > - NBD multi-conn. In my tests this makes a really massive >> >performance difference in certain situations. Again, virt-v2v has >> >a lot of in

Re: qemu-img convert vs writing another copy tool

2020-01-23 Thread Eric Blake
On 1/23/20 12:35 PM, Richard W.M. Jones wrote: I guess some people are aware that virt-v2v, which is a tool which converts guests from VMware to run on KVM, and some other OpenStack-OpenStack migration tools we have, use "qemu-img convert" to copy the data around. Historically we've had bugs her

Re: qemu-img convert vs writing another copy tool

2020-01-23 Thread Richard W.M. Jones
On Thu, Jan 23, 2020 at 07:53:57PM +0100, Max Reitz wrote: > On 23.01.20 19:35, Richard W.M. Jones wrote: > > - NBD multi-conn. In my tests this makes a really massive > >performance difference in certain situations. Again, virt-v2v has > >a lot of information that we cannot pass to qemu

qemu-img convert vs writing another copy tool

2020-01-23 Thread Richard W.M. Jones
I guess some people are aware that virt-v2v, which is a tool which converts guests from VMware to run on KVM, and some other OpenStack-OpenStack migration tools we have, use "qemu-img convert" to copy the data around. Historically we've had bugs here. The most recent was discussed in the thread o

Re: qemu-img convert vs writing another copy tool

2020-01-23 Thread Max Reitz
On 23.01.20 19:35, Richard W.M. Jones wrote: > I guess some people are aware that virt-v2v, which is a tool which > converts guests from VMware to run on KVM, and some other > OpenStack-OpenStack migration tools we have, use "qemu-img convert" to > copy the data around. > > Historically we've had