[one-users] slow live migration of VM's

[Gary S. Cuozzo]

Thank you for the reply. The storage is shared storage via NFS, so no disk data should need to be transferred. Just the running VM. 

I was figuring just the running VM (RAM & state) needs to sync'd. 

The time to transfer wouldn't be such an issue if the VM's were functional during that time. The main issue is that the guests are completely unusable, so the migration may as well not be 'live'. 

Thanks, 
gary 


----- Original Message -----

From: "Ionut Popovici" <ionut at hackaserver.com> 
To: users at lists.opennebula.org 
Sent: Monday, November 25, 2013 2:52:51 AM 
Subject: Re: [one-users] slow live migration of VM's 

1st20- 60Gb disk .. is preaty much .. 
2nd transfer is done via SCP that si a lil slower than any other transfer but is more safer. 
3nd It depends on READ on the host where are the VMS .. if they have other host working .. keep in mind that the machine share the IO of that datastore. On perfect Datastone it sould be around 6ms time to access data on HDD .. but on live datastore it my take a lil more. 
My test was starting nonpersistent image with size 50GB on a SSD drive it took around 4Mins and was not lunch via network, just copy via scp .. on same drive. 
On 11/25/2013 4:32 AM, Gary S. Cuozzo wrote: 



Hi all, 
I was just moving some VM's around as a prep for some server maintenance, via live migration. I moved 3 VM's which were all fairly small in size of 1GB - 3GB RAM and 20GB - 60GB disk. I did the migrations 1 at a time. I was surprised at how long the migrations took and also that each VM was pretty much unusable during the migration. SSH sessions timed out and websites were not able to be accessed. A VM with 3GB RAM allocation took around 10 minutes to migrate. 

Is this typical? Or do I maybe have some sort of issue on my network or config? We run a dedicated 1000Mbps management network for this type of thing, and all data storage access is via separate 4x 1000Mbps bonded channels. I would have expected 3GB of RAM data to be pretty quick. Probably < 1 min. 

Are there any settings in ONE that should be tuned? I don't seem to recall having an issue with migrations when I was just running virt-manager/libvirt directly. 

The last VM I have to move is a pretty important one and it has 24GB RAM allocated. So I think it would be easier/quicker to just shut the VM down, disable the host for maintenance, and redeploy it. I'm hoping to avoid that. 

Thanks for any advice, 
gary 




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