[pve-devel] Baloon Device is the problem! Re: migration problems since qemu 1.3

[Alexandre DERUMIER]

>>It also isn't accepted you get the answer back that 1 isn't a number. 
>>Don't know what format a number needs? 

the default migrate_downtime is 30ms by default (if we doesn't send qmp command).
I think we set 1 sec by default, because of infinite migration (30ms was too short in past with high memory change workload).
I see that last migration code from qemu git (1.4), seem to improve a lot the downtime (from 500 -> 30ms) with high memory change workload.
Don't know if qemu 1.3 works fine without setting downtime to 1sec. 

I think we need to cast the value as int for the json

 vm_mon_cmd($vmid, "migrate_set_downtime", value => $migrate_downtime);

->

 vm_mon_cmd($vmid, "migrate_set_downtime", value => int($migrate_downtime));


I remember same problem with qemu_block_set_io_throttle()
 vm_mon_cmd($vmid, "block_set_io_throttle", device => $deviceid, bps => int($bps), bps_rd => int($bps_rd), bps_wr => int($bps_wr), iops => int($iops), iops_rd => int($iops_rd), iops_wr => int($iops_wr));

So maybe does it send crap if the value is not casted ?  


Also the value should not be int but float, qmp doc said that we can use 0.5, 0.30, as value.



also query-migrate returns some new 2 cools values about downtime, I think we should display them in query migrate log

- "downtime": only present when migration has finished correctly
              total amount in ms for downtime that happened (json-int)
- "expected-downtime": only present while migration is active
                total amount in ms for downtime that was calculated on
		the last bitmap round (json-int)

----- Mail original ----- 

De: "Stefan Priebe" <s.priebe at profihost.ag> 
À: "Alexandre DERUMIER" <aderumier at odiso.com> 
Cc: pve-devel at pve.proxmox.com 
Envoyé: Mercredi 26 Décembre 2012 20:52:56 
Objet: Re: [pve-devel] Baloon Device is the problem! Re: migration problems since qemu 1.3 

Hi, 

Am 26.12.2012 17:40, schrieb Alexandre DERUMIER: 
> I don't know if we really need a default value, because it's always setting migrate_downtime to 1. 
It also isn't accepted you get the answer back that 1 isn't a number. 
Don't know what format a number needs? 

> Now, I don't know what really happen to you, because recent changes can set migrate_downtime to the target vm (vm_mon_cmd_nocheck) 
> But I don't think it's doing something because the migrate_downtime should be done one sourcevm. 
You get the error message that 1 isn't a number. If i get this message 
migration fails after. 

> Can you try to replace vm_mon_cmd_nocheck by vm_mon_cmd ? (So it should works only at vm_start but not when live migrate occur on target vm) 
Done - works see my other post. 

Stefan