Network Card Settings For Private Connections Between Nodes

As discussed with Jr. DBA there were “Global Cache Blocks Lost wait event” observed in RAC Database
We also notified that network packet dropped on interface level whenever server reboot issues faced .

I came to know one good Oracle RAC Recommendations for Private Network NIC Configuration
Flow control: control is the process of managing the rate of data transmission between two nodes to prevent a fast sender from outrunning a slow receiver. It provides a mechanism for the receiver to control the transmission speed, so that the receiving node is not overwhelmed with data from sending nodes. Flow control should be distinguished from congestion control. Oracle recommends that for the flow control Rx=on tx=off

You can check RX and TX using below command
ethtool -a eth1

For private connections ORACLE recommends the RX flow control to be on and TX to be off. So I made the changes.

ethtool -A eth1 rx on tx off autoneg on

However the changes are lost when the server reboots. So I added the command to /etc/rc.local file to make the changes persistent.

As a result the network card settings for the private connection should be:

full duplex, autoneg on, rx on , tx off

http://www.oracleportal.org/knowledge-base/real-application-clusters-(rac)/administration/network-card-settings-for-private-connections-between-nodes.aspx
http://linuxtoolkit.blogspot.in/2012/02/using-ethtool-to-manage-ethernet-card.html
http://gjilevski.com/2011/08/02/oracle-cache-fusion-private-inter-connects-and-practical-performance-management-considerations-in-oracle-rac/
http://www.oracle.com/technetwork/products/clustering/overview/s298716-oow2008-perf-130776.pdf

http://www.linkedin.com/groups/Is-flow-control-rx-on-3156190.S.5897450465913745410?view=&item=5897450465913745410&type=member&gid=3156190&trk=eml-b2_anet_digest-hero-5-hero-disc-0&midToken=AQEuR3SGIgS5Og&fromEmail=fromEmail&ut=00vcHPcUOPK6k1

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.