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Re: [Xen-users] Xen + IPv6 + Netapp = NFS read problem

On Sun, Nov 18, 2012 at 06:08:03PM +0100, G.Bakalarski@xxxxxxxxxx wrote:
> We have some 100 virtual servers - we use Xen 4.1 for virtualisation.
> A basics OS is Debian Squeeze with some backports packages (newer kernel,
> newer xen, newer nfs commons etc)

This combination is not supported.

> During test on our testbed system we could read about 250-280 MBytes/s
> from our netapp storage (using 10GBit network). The backup server is
> connected using 1GBit/s network so we expected some 100MBytes/s performance.

So you have one working and one not really working setup? How do they

> We tried to find a reason of such slow performance and it looks like
> it is somewhere between xen bridge and Xen domU and a KEY FACTOR IS IPv6.

Below you also show that another key factor is NetApp vs. Linux.

> All mounts use NFS version 3 and proto tcp6.

Please show the mount options from /proc/mounts. Also you want to use

> We checked  MTUs - everywhere 1500. No errors on any side (switch, netapp,
> linux clients)... IPv4 connections performs just fine.

1500 is too low. You want to use 9000 for anything with a lot of

> ssh/scp and others IPv6 services perform OK ...

ssh between NetApp and the server? Otherwise this is no real test.

> Any hints?

You want to use OpenVSwitch for stuff that produces a lot of traffic.


Killing is wrong.
                -- Losira, "That Which Survives", stardate unknown

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