[PVE-User] Speed problem

Emmanuel Kasper e.kasper at proxmox.com
Tue Jun 2 14:46:26 CEST 2015

Hi Luis

On 06/02/2015 02:25 PM, Luis G. Coralle wrote:
> Hello everyone.
> I have two VMs on a bridge ( eg vmbr3 ) that is not assigned to any
> physical network card, that is, VMs are isolated on a LAN segment.
> Both VMs have virtio bus, qcow2, virtio network card, 512 MB of RAM. At one
> point, I start a scp 3GB file ( eg /var/www/image.iso ) to copy from VM to
> another and transfer rate starts at normal speed and then extremely low to
> 360Kb/s or less.

What local sequencial write speed do you achieve in your VM ?

To measure that you can install bonnie++ and run bonnie++ -d /tmp

An example output is:

django consummer hard drive 2014
jeudi 1 janvier 2015, 21:19:23 (UTC+0100)
Version  1.97       ------Sequential Output------ --Sequential Input-
Concurrency   1     -Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
/sec %CP
django        7536M   729  96 106440  10 33460   4  4160  94 86945   5
188.3   3
Latency             17694us     229ms    9485ms   24075us    1151ms

here the number you're interested is Sequencial Output / Block / K /Sec
on this system it translates to 103MB/s

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