Re: [Xen-users] Xen and networking.

[tmac <tmacmd@xxxxxxxxx>]

NetApp GX with two heads and 10GigE's.
Measured at over 2Gigabytes/sec!
Should easily handle 200MBytes/sec

Network path:

VirtHostA -GigE-> 4948-10G (port 1 )-10gigE-> 6509 -> -10GigE-> NetApp
VirtHostB -GigE-> 4948-10G (port 17)-10gigE-> 6509 -> -10GigE-> NetApp

On Dec 28, 2007 7:30 PM, Stephan Seitz <s.seitz@xxxxxxxxxxxx> wrote:
> Don't get me wrong,
>
> but my first thought was: What is the maximum expected throughput of the
> nfs server? It should at least be connected with 2 GBit/s to the switch,
> to serve two dd's with each ~100MB/s.
>
> Well, I assume both domU's are using the same nfs server.
>
>
> Regards,
>
> Stephan
>
>
> tmac schrieb:
>
> > I have a beefy machine
> > (Intel dual-quad core, 16GB memory 2 x GigE)
> >
> > I have loaded RHEL5.1-xen on the hardware and have created two logical 
> > systems:
> > 4 cpus, 7.5 GB memory 1 x Gige
> >
> > Following RHEL guidelines, I have it set up so that eth0->xenbr0 and
> > eth1->xenbr1
> > Each of the two RHEL5.1 guests uses one of the interfaces and this is
> > verified at the
> > switch by seeing the unique MAC addresses.
> >
> > If I do a crude test from one guest over nfs,
> > dd if=/dev/zero of=/nfs/test bs=32768 count=32768
> >
> > This yields almost always 95-100MB/sec
> >
> > When I run two simultaneously, I cannot seem to get above 25MB/sec from 
> > each.
> > It starts off with a large burst like each can do 100MB/sec, but then
> > in a couple
> > of seconds, tapers off to the 15-40MB/sec until the dd finishes.
> >
> > Things I have tried (installed on the host and the guests)
> >
> >  net.core.rmem_max = 16777216
> >  net.core.wmem_max = 16777216
> >  net.ipv4.tcp_rmem = 4096 87380 16777216
> >  net.ipv4.tcp_wmem = 4096 65536 16777216
> >
> >  net.ipv4.tcp_no_metrics_save = 1
> >  net.ipv4.tcp_moderate_rcvbuf = 1
> >  # recommended to increase this for 1000 BT or higher
> >  net.core.netdev_max_backlog = 2500
> >  sysctl -w net.ipv4.tcp_congestion_control=cubic
> >
> > Any ideas?
> >
> >
>
>
> --
> Stephan Seitz
> Senior System Administrator
>
> *netz-haut* e.K.
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>
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>
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>
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>
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>



-- 
--tmac

RedHat Certified Engineer #804006984323821 (RHEL4)
RedHat Certified Engineer #805007643429572 (RHEL5)

Principal Consultant, RABA Technologies

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