[pve-devel] adding live migration options ? (xbzlre, compression, ...)

Cesar Peschiera brain at click.com.py
Sun Sep 27 05:29:08 CEST 2015


A question:
I guess that will be compatible with:

/etc/pve/datacenter.cfg :
migration_unsecure: 1

Right?

----- Original Message ----- 
From: "Alexandre DERUMIER" <aderumier at odiso.com>
To: "dietmar" <dietmar at proxmox.com>
Cc: "pve-devel" <pve-devel at pve.proxmox.com>
Sent: Friday, September 25, 2015 7:44 AM
Subject: Re: [pve-devel] adding live migration options ? (xbzlre, 
compression, ...)


>I have tested xbzrle & compression.
>
> xbzrle seem to be pretty fine, I don't have bug with it. (tested with 
> video player running in guest)
> also they are no overhead on 10gbe network
>
> without xbzlre:
> Sep 25 12:52:18 migration speed: 1092.27 MB/s - downtime 66 ms
>
> with xbzlre:
> Sep 25 13:30:17 migration speed: 1129.93 MB/s - downtime 162 ms
>
>
>
> now for compression (default option), I have a big big overhead
>
> Sep 25 13:36:39 migration speed: 352.34 MB/s - downtime 450 ms
> and source kvm process jump to 800% (on a xeon-e5 3,1ghz)
>
>
> I think we can enable xbzrle by default, but for compression,
> I really not sure it's a good idea. (depend on cpu/network bandwith)
>
>
>
> ----- Mail original -----
> De: "dietmar" <dietmar at proxmox.com>
> À: "aderumier" <aderumier at odiso.com>
> Cc: "pve-devel" <pve-devel at pve.proxmox.com>
> Envoyé: Jeudi 24 Septembre 2015 11:45:08
> Objet: Re: [pve-devel] adding live migration options ? (xbzlre, 
> compression, ...)
>
>> >>I think those are special cases, and it is always better to enable
>> >>compression,
>> >>because
>> >>it reduces traffic on the network.
>>
>> the kvm forum slides, they said that with compression, the migration is 
>> slower
>>
>> on 10gbit network.
>
> Don't get me wrong, but this depends on many, many factors. I am sure this 
> is
> true
> if you run a single migration. But the picture is totally different if you 
> run
> on a real network which is used by many other VMs. Or if you run more than 
> one
> migration
> at same time.
>
>> >>But do we already use lz4?
>> Currently we don't have implemented live migration compress. (it's a new
>> feature from qemu 2.4)
>>
>>
>> I'll make a basic patch to enable compression, and will do some benchmark 
>> with
>> 10gbe network.
>
> Great.
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