Posted by Riyaj Shamsudeen on May 22, 2012
Let’s first discuss how RAC traffic works before continuing. Environment for the discussion is: 2 node cluster with 8K database block size, UDP protocol is used for cache fusion. (BTW, UDP and RDS protocols are supported in UNIX platform; whereas Windows uses TCP protocol).
UDP protocol, fragmentation, and assembly
UDP Protocol is an higher level protocol stack, and it is implemented over IP Protocol ( UDP/IP). Cache Fusion uses UDP protocol to send packets over the wire (Exadata uses RDS protocol though).
MTU defines the Maximum Transfer Unit of an IP packet. Let us consider an example of MTU set to 1500 in a network interface. One 8K block transfer can not be performed with just one IP packet as the IP packet size (1500 bytes) is less than 8K. So, one transfer of UDP packet of 8K size is fragmented to 6 IP packets and sent over the wire. In the receiving side, those 6 packets are reassembled to create one UDP buffer of size 8K. After the assembly, that UDP buffer is delivered to an UDP port of a UNIX process. Usually, a foreground process will listen on that port to receive the UDP buffer.
Read the rest of this entry »
Posted in 11g, Oracle database internals, Performance tuning, Presentations, RAC, video | Tagged: cache fusion mtu, fragmentation and reassembly, gc lost packets, ipfrag_high_thres, ipfrag_low_thres, ipfrag_time, Jumbo frames, MTU, MTU=9000, oracle performance, RAC internals, RAC performance, RAC presentations, RAC training, RAC video, RAC videos, RDS, UDP vs tcp, wireshark | 10 Comments »
Posted by Riyaj Shamsudeen on February 27, 2012
Just a quick note, I will be conducting next 2-week advanced RAC Training, online class in March 26-30 and April 9-13.
You can find agenda and other details here .
I received few emails about the training outline. You can find the outline below:
Yes, I do accept Purchase Orders and can invoice you :)
Posted in Presentations, RAC | Tagged: RAC, RAC training, training online | 1 Comment »
Posted by Riyaj Shamsudeen on January 20, 2012
This video was created circa July 2011. Click the Read More link to review the video. Version Oracle Database 188.8.131.52
Synopsis: Essentially, we probe the importance of LMS processes using DTrace. Explain why LMS should run in elevated priority. How to review deep statistics about LMS processes and much more.
Posted in Oracle database internals, Performance tuning, Presentations, RAC, video | Tagged: LMS tuning, oracle performance, RAC performance, RAC training, video RAC training | 7 Comments »
Posted by Riyaj Shamsudeen on July 5, 2011
I will be delivering an intense, advanced 2-week RAC training seminar in Aug 22-26 and Sep 19-23 with numerous demos, dumps and scripts. We will meet 4 hours per day, in a virtual world, 8AM-12 Noon Pacific time for those two weeks. Tanel has written has a great blog post about this seminar series Advanced RAC training.
If you like my presentations about RAC and performance tuning, you will love my seminar series. You will gain better understanding about RAC internals, and you will be able to advance your debugging and performance tuning skills attending my seminar series.
Join me and Let’s explore RAC further.
Posted in Oracle database internals, Performance tuning, Presentations, RAC | Tagged: oracle performance, rac online training, RAC performance, RAC training, seminar | 5 Comments »