Re: 10Gbps latency

I can put a bet of $1 on this - this customer is using VMware virtulized
environment with HP srv (most likely) and Intel ethernet LAN chipset.

Check out TFO setting on LINUX machine and VMWARE host.
Make sure on Host TFO is enabled and on Guest it's disabled.

Also in oracle rack HA file (.conf) make sure that the parameters are
non-default. Most Oracle admin leave parameters default and it's not
optimum.

Seen this many time.

On Tue, Jul 12, 2011 at 12:59 AM, Joseph L. Brunner <joe_at_affirmedsystems.com
> wrote:

> Hi Marc,
>
> I face these debates/questions on almost a daily basis so I feel for you
> man...
>
> Can you confirm the following:
>
> 1. Are you trying to access iscsi storage or is this simply oracle
> replication traffic?
>
> 2. Are you using the very latest nic drivers on each server?
>
> 3. Can you confirm disk queue, raid level, raid performance and other
> NON-NETWORK related things have been checked and blessed by the server
> priest ordained at your location?
>
>
> Thanks,
>
> Joe
>
> -----Original Message-----
> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
> marc abel
> Sent: Monday, July 11, 2011 9:48 AM
> To: ccielab_at_groupstudy.com
> Subject: OT: 10Gbps latency
>
> Hello all,
>
> I have an issue where we have a 10gbps backbone, and our blade chassis
> are also 10gbps however the actual blades themselves are only 1gbps.
> This links are no where near saturated. Even the 10Gbps uplinks rarely
> carry over 50Mbps of traffic.
> We are having some performance issues with Oracle RAC, and the DB guys
> are of course trying to blame the network. They are claiming that
> upgrading the blades to 10Gbps will solve all our issues. I have
> explained that we are not saturating the links, we are seeing no
> discarding/queuing/etc, but they insist that we will see improvements
> in latency by upgrading the blades. They are basing all of this
> anecdotally on the fact that one of the DB developers ran into this
> at his previous employer and that is how they solved it.
>
> Most of the Cisco spec sheets I have found do show an improvement in
> latency when comparing Multiple 1Gbps links to 10Gbps, but seem to
> make the assumption that some of these links are saturated. This makes
> sense, but what about in the absence of much traffic, is a 10Gbps link
> "faster" than a 1Gbps link?
>
> I remain unconvinced that it will make a bit of difference, but would
> like to hear other opinions.
>
> Thank you,
>
> Marc
>
>
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Received on Tue Jul 12 2011 - 13:33:30 ART