[PVE-User] Slow speeds when KVM guest is on NFS

Gerald Brandt gbr at majentis.com
Tue Nov 15 16:09:46 CET 2016


I don't know if it helps, but I always switch to NFSv4.

nfs: storage
     export /proxmox
     server 172.23.4.16
     path /mnt/pve/storage
     options vers=4
     maxfiles 1
     content iso,backup,images

Gerald

On 2016-11-15 08:48 AM, Mikhail wrote:
> Hello,
>
> Please help me to find why I'm seeing slow speeds when KVM guest is on
> NFS storage. I have pretty standard setup, running Proxmox 4.1-1. The
> storage server is on NFS connected directly (no switches/hubs, direct
> NIC-to-NIC connection) via Gigabit ethernet.
>
> I just launched Debian-8.3 stock ISO installation on the KVM guest
> that's disk resides on NFS and I'm seeing some terribly slow file copy
> operation speeds on debian install procedure - about 200-600
> kilobyte/second according to "bwm-ng" output on storage server. I also
> tried direct write from my Proxmox host via NFS using "dd" and results
> are showing near 1gbit speeds:
>
> # dd if=/dev/zero of=10G bs=1M count=10000
> 10000+0 records in
> 10000+0 records out
> 10485760000 bytes (10 GB) copied, 115.951 s, 90.4 MB/s
>
> What could be an issue?
>
> On Proxmox host:
>
> # cat /proc/mounts |grep vmnf
> 192.168.4.1:/mnt/vmnfs /mnt/pve/vmnfs nfs
> rw,relatime,vers=3,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=192.168.4.1,mountvers=3,mountport=47825,mountproto=udp,local_lock=none,addr=192.168.4.1
> 0 0
>
> storage.cfg:
> nfs: vmnfs
> 	export /mnt/vmnfs
> 	server 192.168.4.1
> 	path /mnt/pve/vmnfs
> 	content images
> 	options vers=3
> 	maxfiles 1
>
> KVM guest config:
> # cat /etc/pve/qemu-server/85103.conf
> bootdisk: virtio0
> cores: 1
> ide2: ISOimages:iso/debian-8.3.0-amd64-CD-1.iso,media=cdrom
> memory: 2048
> name: WEB
> net0: virtio=3A:39:66:30:63:32,bridge=vmbr0,tag=85
> numa: 0
> onboot: 1
> ostype: l26
> smbios1: uuid=97ea543f-ca64-43ab-9d66-9d1c9cd179b0
> sockets: 1
> virtio0: vmnfs:85103/vm-85103-disk-1.qcow2,size=50G
>
> Any suggestions where to start looking is greatly appreciated.
>
> Thanks.
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>



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