Re: [Qemu-devel] blockdev-mirror , how to replace old nodename by new nodename ?

[Alexandre DERUMIER]

Ok, I have same result than my test:

{"iops_rd": 0, "detect_zeroes": "off", "image": {"virtual-size": 1073741824, 
"filename": "base.raw", "format": "raw", "actual-size": 0, "dirty-flag": 
false}, "iops_wr": 0, "ro": false, "node-name": "node1", "backing_file_depth": 
0, "drv": "raw", "iops": 0, "bps_wr": 0, "write_threshold": 0, "encrypted": 
false, "bps": 0, "bps_rd": 0, "cache": {"no-flush": false, "direct": false, 
"writeback": true}, "file": "base.qcow2, "encryption_key_missing": false}, 
{"iops_rd": 0, "detect_zeroes": "off", "image": {"virtual-size": 1073741824, 
"filename": "base.qcow2", "format": "file", "actual-size": 0, "dirty-flag": 
false}, "iops_wr": 0, "ro": false, "node-name": "#block194", 
"backing_file_depth": 0, "drv": "file", "iops": 0, "bps_wr": 0, 
"write_threshold": 0, "encrypted": false, "bps": 0, "bps_rd": 0, "cache": 
{"no-flush": false, "direct": false, "writeback": true}, "file": "base.qcow2", 
"encryption_key_missing": false}, 


{"iops_rd": 0, "detect_zeroes": "off", "image": {"virtual-size": 1073741824, 
"filename": "target.qcow2", "cluster-size": 65536, "format": "qcow2", 
"actual-size": 352256, "format-specific": {"type": "qcow2", "data": {"compat": 
"1.1", "lazy-refcounts": false, "refcount-bits": 16, "corrupt": false}}, 
"dirty-flag": false}, "iops_wr": 0, "ro": false, "node-name": "foo", 
"backing_file_depth": 0, "drv": "qcow2", "iops": 0, "bps_wr": 0, 
"write_threshold": 0, "encrypted": false, "bps": 0, "bps_rd": 0, "cache": 
{"no-flush": false, "direct": false, "writeback": true}, "file": 
"target.qcow2", "encryption_key_missing": false}, {"iops_rd": 0, 
"detect_zeroes": "off", "image": {"virtual-size": 1074135040, "filename": 
"target.qcow2", "format": "file", "actual-size": 352256, "dirty-flag": false}, 
"iops_wr": 0, "ro": false, "node-name": "#block008", "backing_file_depth": 0, 
"drv": "file", "iops": 0, "bps_wr": 0, "write_threshold": 0, "encrypted": 
false, "bps": 0, "bps_rd": 0, "cache": {"no-flush": false, "direct": false, 
"writeback": true}, "file": "target.qcow2", "encryption_key_missing": false}]}


What I don't understand is how do you map device to the blockdev ?

qemu doc said something like

-device virtio-blk,drive=blk0 where blk0 is the nodename.

but when I blockdev-mirror, the target blockdev has a new nodename.
So how does it work ?


----- Mail original -----
De: "Kashyap Chamarthy" <address@hidden>
À: "aderumier" <address@hidden>
Cc: "qemu-devel" <address@hidden>
Envoyé: Mercredi 19 Avril 2017 14:58:01
Objet: Re: [Qemu-devel] blockdev-mirror , how to replace old nodename by new 
nodename ?

On Wed, Apr 19, 2017 at 02:28:46PM +0200, Alexandre DERUMIER wrote: 
> Thanks I'll try. (I'm on 2.9.0-rc4) 
> 
> can you send your initial qemu command line ? 

$ ~/build/qemu-upstream/x86_64-softmmu/qemu-system-x86_64 \ 
-display none -nodefconfig -nodefaults -m 512 \ 
-device virtio-scsi-pci,id=scsi -device virtio-serial-pci \ 
-blockdev 
node-name=foo,driver=qcow2,file.driver=file,file.filename=./base.qcow2 \ 
-monitor stdio -qmp unix:./qmp-sock,server,nowait 

> also : 
> 
> >>"execute":"blockdev-add", 
> >>"arguments":{ 
> >>"driver":"qcow2", 
> >>"node-name":"node1", 

Oops, it should be 'node2'. Copy / paste mistake, sorry. 

> ... 
> 
> then 
> 
> 
> >>"execute":"blockdev-mirror", 
> >>"arguments":{ 
> >>"device":"foo", 
> >>"job-id":"job-2", 
> >>"target":"node2", --> node2 ? 
> >>"sync":"full" 

With the above copy / paste error I noted in the `blockdev-add` command, 
the commands I noted in my previous email should work as expected. 

Regards, 
Kashyap 

> ----- Mail original ----- 
> De: "Kashyap Chamarthy" <address@hidden> 
> À: "aderumier" <address@hidden> 
> Cc: "qemu-devel" <address@hidden> 
> Envoyé: Mercredi 19 Avril 2017 12:43:00 
> Objet: Re: [Qemu-devel] blockdev-mirror , how to replace old nodename by new 
> nodename ? 
> 
> On Wed, Apr 19, 2017 at 09:08:20AM +0200, Alexandre DERUMIER wrote: 
> > Hi, 
> > 
> > I'm trying to implement blockdev-mirror, to replace drive-mirror as we 
> > can pass more options with blockdev-mirror. 
> > 
> > 
> > I would like to mirror an attached blockdev to a new blockdev, then 
> > switch at the end of block-job-complete, like for drive-mirror. 
> 
> [...] 
> 
> > blockdev-mirror: 
> > 
> > {"arguments":{"job-id":"drive-virtio0","target":"tempmirror","sync":"full","replaces":"drive-virtio0","device":"drive-virtio0"},"execute":"blockdev-mirror"}
> >  
> > 
> > (I have try with or without replaces option) 
> > 
> > then query-name-block-nodes, show vm-138-disk-2.raw file on tempmirror 
> > "node-name", and vm-138-disk1.qcow2 on "drive-virtio0" node-name 
> > 
> > I expected that both was switched, like for drive-mirror. 
> 
> For me, 'blockdev-mirror' does do the switch when I issue 
> 'block-job-complete' (similar to 'drive-mirror') 
> 
> The below is my test from Git: 
> 
> I was here (on Git): 
> 
> $ git describe 
> v2.9.0-rc5 
> 
> ----------------------------------------------------------------------- 
> $ qemu-img create -f qcow2 /export/target2.qcow2 1G 
> Formatting '/export/target2.qcow2', fmt=qcow2 size=1073741824 encryption=off 
> cluster_size=65536 lazy_refcounts=off refcount_bits=16 
> ----------------------------------------------------------------------- 
> QMP> 
> { 
> "execute":"blockdev-add", 
> "arguments":{ 
> "driver":"qcow2", 
> "node-name":"node1", 
> "file":{ 
> "driver":"file", 
> "filename":"/export/target2.qcow2" 
> } 
> } 
> } 
> {"return": {}} 
> ----------------------------------------------------------------------- 
> QMP> 
> {"execute":"query-named-block-nodes"} 
> [...] 
> ----------------------------------------------------------------------- 
> QMP> 
> { 
> "execute":"blockdev-mirror", 
> "arguments":{ 
> "device":"foo", 
> "job-id":"job-2", 
> "target":"node2", 
> "sync":"full" 
> } 
> } 
> {"return": {}} 
> {"timestamp": {"seconds": 1492598410, "microseconds": 35946}, "event": 
> "BLOCK_JOB_READY", "data": {"device": "job-2", "len": 24182784, "offset": 
> 24182784, "speed": 0, "type": "mirror"}} 
> ----------------------------------------------------------------------- 
> QMP> 
> { 
> "execute":"block-job-complete", 
> "arguments":{ 
> "device":"job-2" 
> } 
> } 
> {"return": {}} 
> {"timestamp": {"seconds": 1492598419, "microseconds": 115458}, "event": 
> "BLOCK_JOB_COMPLETED", "data": {"device": "job-2", "len": 24182784, "offset": 
> 24182784, "speed": 0, "type": "mirror"}} 
> ----------------------------------------------------------------------- 
> 
> 
> [...] 
> 
> 
> -- 
> /kashyap 
>