[j-nsp] CoS on iSCSI ports
eugen at imacandi.net
Tue Oct 28 19:09:49 EDT 2014
If memory serves me right, the 5% bandwidth is actually prioritized when
you do something on the switch via SSH/Telnet/J-Web so that in case your
switch is running line-rate, you can actually log into it.
Also, disable flow-control, it's not helping.
On Wed, Oct 15, 2014 at 2:49 AM, Mike Gonnason <gonnason at gmail.com> wrote:
> For my iSCSI stuff, I have been disabling pause frames as they are not
> really beneficial for my situation. I had a NetApp (forget what model) that
> would saturate a 10Gb link and the Juniper would send a pause frame with
> the result of dropping all connections across that trunk. Not very helpful.
> You can try modifying the NC class and alter how the scheduling is
> performed. in section 21 you can see 5% is specified for the NC scheduler.
> -Mike Gonnason
> On Tue, Oct 14, 2014 at 3:39 PM, Josh Farrelly <Joshf at originit.co.nz>
> > Hi all.
> > We have 2x EX4550's in VC that provide switching for an iSCSI network.
> > There are 3 Dell SANs and 4 Dell R820 ESXi hosts connected via twinax @
> > 10Gbps. Jumbo frames and flow control is enabled.
> > My knowledge around Juniper tech is a little vague, but what's with the
> > default CoS settings on the switch? It seems they will automatically
> > reserve 5% for network control traffic. Is there anyway to disable CoS
> > entirely? AFAIK Brocade & Cisco don't have this type of default, and 5%
> > a 10Gbps is actually a rather significant chunk of bandwidth.
> > The reason I'm asking is that we've seen some performance issues lately.
> > We have a hybrid-SSD tray of storage that can saturate a link, so we're
> > seeing MAC pause frames being received by the switch as well as discards
> > some of the queues.
> > Thanks for any pointers.
> > Regards,
> > Josh.
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