To augment what both Matthew and Alfredo have said...
TCP "jumbo frames" are used mainly with network-attached storage (i.e.
NFS, iSCSI, etc) and for special use-cases like the Oracle RAC
interconnect. The standard 1500-byte packets are sized to optimally
accommodate network traffic ranging from acknowledgement messages of a
few bytes to database storage traffic of 8192 bytes and larger.
Larger packet sizes doesn't make the packets move any faster over the
wire or through switches and routers, but simply results in fewer
packets because an 8192-byte database block fits within one 9000-byte
packet, instead of requiring six 1500-byte packets. This results in
fewer un-marshalling operations on the source server and fewer
marshalling operations on the destination server, so the ultimate
increase in network throughput actually comes from less CPU consumption
by the servers on either end of the network connection. The CPU savings
on each server, as well as the network throughput, can be significant,
but when there is a consistently high volume of such large-packet
traffic. In low-volume situations, it is difficult to measure any benefit.
CPU-saturated servers using network-attached storage without jumbo
frames can result in poor I/O performance without network saturation
being detectable. DBAs will report the poor I/O latency and throughput
over NFS storage, but the network administrator will correctly respond
that there is no network throughput or latency issues. Meanwhile,
server administrators will surely detect the CPU saturation, but not
associate it with the poor I/O performance over NAS, likely because they
won't be involved in the I/O performance discussion, and neither the DBA
nor the network admin will make the connection.
So, deploying jumbo frames can be a reactive measure when CPU saturation
is detected and associated to NAS I/O issues, or it can be a proactive
measure to prevent that situation.
On 11/11/16 13:10, Dimensional DBA wrote:
As Alfredo mentions you normally don’t use jumbo frames on the public facing networks as none of the clients normally have jumbo frames setup. This could be different if you were using say citrix desktops and ewveryone used those to access their applications then what you want may work.
I have also used jumbo frames on storage networks to netapps or other network storage.
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*From:*oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] *On Behalf Of *Alfredo Abate
*Sent:* Friday, November 11, 2016 11:55 AM
*To:* Jeff Chirco
*Cc:* kathy duret; oracle-l@xxxxxxxxxxxxx
*Subject:* Re: jumbo frames with non rac
Jeff,
My understanding of using jumbo frames with Oracle RAC is to be able to increase the packet size of the */private interconnect/* (heartbeat) of the cluster for better performance. This is normally done on segregated switches (or switch ports), NICs, etc so that they are all configured for the larger MTU size (9000).
If you are considering enabling jumbo frames on the *public network* of a single instance (or even RAC) database server that your application servers or end users will directly be connecting to it can cause issues since most networks are configured for the normal MTU size (1500). This mismatch will potentially cause network issues such as packet drops when the two devices are communicating with each other.
Alfredo
On Fri, Nov 11, 2016 at 12:38 PM, Jeff Chirco <backseatdba@xxxxxxxxx <mailto:backseatdba@xxxxxxxxx>> wrote:
Sorry yes Oracle Linux 7 here and with hugepages. 11g database currently but plans to 12c.
On Fri, Nov 11, 2016 at 9:15 AM, kathy duret <katpopins21@xxxxxxxxx <mailto:katpopins21@xxxxxxxxx>> wrote:
I am assuming Linux here ...
You will also need to set up hugepages and there are some other settings to consider like semaphores.
There are many papers on how to do set this up. I would look on MOS first and then go fro there.
*Kathy Duret*
**
------------------------------------------------------------------------
*From:*Jeff Chirco <backseatdba@xxxxxxxxx <mailto:backseatdba@xxxxxxxxx>>
*To:* "oracle-l@xxxxxxxxxxxxx <mailto:oracle-l@xxxxxxxxxxxxx>" <oracle-l@xxxxxxxxxxxxx <mailto:oracle-l@xxxxxxxxxxxxx>>
*Sent:* Friday, November 11, 2016 10:30 AM
*Subject:* jumbo frames with non rac
We are in the middle of setting up replacing new database servers and been wondering about jumbo frames. We have 10gb network and we don't run RAC and not sure if we ever will but wondering if there still is a big benefit for jumbo frames? We also are running a new NetApp all flash storage.
From what I have read so far is yes there is a benefit but just wondering if anyone has any opinions? I am not very knowledgeable on the network side of things.
Thanks,
Jeff
