David Boyes wrote:

> Dedicate the adapter to VM. OSA sharing is complicated and hard to set up.

I'm not sure what you see as complicated on sharing the OSA-E devices,
other than doing the IOCP (and with Linux running in an LPAR they already
have that done to share with MVS). When you use a virtual machine with
Linux or VM TCP/IP as a router there's also changes to your IP network
that can be difficult to get done.

IMHO the choice for giving Linux virtual machines their own OSA device or
a connection to a virtual router should be driven by things like bandwidth
usage and network latency. Setup is a one-time issue, but poor performance
is something for every day. You should expect network devices to operate
more efficient at higher bandwidth in general. If you run all your traffic
through a single OSA device you save CPU resources (at the cost of higher
latency). This efficiency improvement at high bandwidth is less obvious
for virtual network devices like IUCV because much of the CPU cycles are
spent on copying data between virtual machines.

So the short answer would be to use virtual routers in between, unless
you have very specific bandwidth or latency requirements. And even with
such requirements, the availability of network drivers for your kernel
may force you to use a virtual router anyway.

Rob

Reply via email to