Re: 10Gbps latency

Spot on except this isn't a VMWARE environment.

On Mon, Jul 11, 2011 at 10:33 PM, Radioactive Frog <pbhatkoti_at_gmail.com> wrote:
> 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 - 08:43:36 ART