how about implement block_stream and block-job-set-speed in transaction? Then a block_stream + block-job-set-speed or __com.redhat.drive-mirror + block-job-set-speed transaction should work.

According to bug description, qe can reproduce with qemu-kvm-rhev-278,mark qa_ack+
(qemu) block-job-set-speed ide1-cd0 1M
Device 'ide1-cd0' has not been activated by the guest

v2 of upstream patch proposal:
https://lists.gnu.org/archive/html/qemu-devel/2012-04/msg03510.html

- change block-job-set-speed to use parameter name 'speed' instead of 'value'
- add optional 'speed' parameter to 'block-stream'
- add optional 'speed' parameter to '__com.redhat_drive-mirror'

Updating the title; the upstream qemu solution appears to be headed towards setting the speed as part of starting a job, at which point it would still be an expected error to attempt to set the speed while a job is not running; the difference in verification would be checking that the optional parameter is present when starting the job and setting speed in one monitor call rather than the current constraint of two separate calls.

Posted to rhvirt

    Technical note added. If any revisions are required, please edit the "Technical Notes" field
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    New Contents:
No Documentation Needed

Verified on qemu-kvm-rhev-0.12.1.2-2.292.el6.x86_64:

1. mirroring with speed set to 10M at beginning, after steady state, reopen to target, reboot guest, guest works correctly:

{ "execute" : "__com.redhat_drive-mirror", "arguments" : { "device" : "drive-virtio-disk0", "target" : "/dev/disk/by-path/ip-10.66.9.64:3260-iscsi-iqn.2001-04.com.example:storage.disk1.amiens.sys1.xyz-lun-2", "format": "qcow2", "mode": "absolute-paths", "speed": 10485760, "full" : false } }
{"return": {}}

{ "execute": "__com.redhat_drive-reopen", "arguments": {"device": "drive-virtio-disk0", "new-image-file": "/dev/disk/by-path/ip-10.66.9.64:3260-iscsi-iqn.2001-04.com.example:storage.disk1.amiens.sys1.xyz-lun-2", "format": "qcow2" } }
{"timestamp": {"seconds": 1337189124, "microseconds": 258318}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "drive-virtio-disk0", "len": 21474836480, "offset": 21474836480, "speed": 109951162777600, "type": "mirror"}}
{"return": {}}

2. streaming with speed set to 10M

{ "execute": "blockdev-snapshot-sync", "arguments": { "device": "drive-virtio-disk0", "snapshot-file": "/dev/disk/by-path/ip-10.66.9.64:3260-iscsi-iqn.2001-04.com.example:storage.disk1.amiens.sys1.xyz-lun-2", "mode": "absolute-paths", "format": "qcow2" } }
{"return": {}}

{ "execute": "block-stream", "arguments": { "device": "drive-virtio-disk0", "speed": 10485760 } }
{"return": {}}

{"timestamp": {"seconds": 1337265302, "microseconds": 451952}, "event": "BLOCK_JOB_COMPLETED", "data": {"device": "drive-virtio-disk0", "len": 21474836480, "offset": 21474836480, "speed": 1099511627776000, "type": "stream"}}


Based on above results, fixed.

Moving to VERIFIED as per Comment #2 and Comment #13

Doc has not been modified, open new one to track:
Bug 824338 - invalid argument in block-job-set-speed document

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHBA-2012-0746.html