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Running an optional system check for LLT

Run this check to ensure the proper setup of LLT.

 To run an optional system check for LLT

1. Log in as root user.
2. Navigate to the directory containing the installation program:
   • For RHEL 4.0 on x86_64:

     # cd

     /mnt/cdrom/rhel4_x86_64/storage_foundation_for_oracle_rac

   • For SLES9 on x86_64:

     # cd

     /mnt/cdrom/sles9_x86_64/storage_foundation_for_oracle_rac

3. Launch the SF Oracle RAC configuration menu:

   # ./installsfrac -configure

   By default, the installsfrac program uses SSH for remote communication. However, to use RSH, specify the -rsh option with the installsfrac program.

   # ./installsfrac -rsh -configure

4. Enter the system names.

   Enter the system names separated by spaces on whcih to configure SFRAC: galaxy nebula

5. From the main menu, select Check systems for SFRAC **INSTRUCTIONS ONLY **.
6. Select Check LLT links **INSTRUCTIONS ONLY**.
7. The installer lists the conditions for LLT links for each of the cluster systems and shows example commands for checking and changing settings. You must log in to each cluster system to make the checks. For example:

   ...........................................

   Before continuing, login to all cluster nodes and check LLT links.Each LLT link must:

   * Not share a subnet with other LLT links on that system.

   * Have speed and autonegotiate settings matching the switch

   port

   * Have same jumbo frame settings

   * Must have unique MAC addresses

   Example:

   /sbin/ethtool -a eth1 #to query speed and autonegotiate

   /sbin/ethtool -a eth1 #to query jumbo frames

   ..............................................................

Auto-negotiation, media speed, and jumbo frame settings
on private NICs

For optimal LLT (Low Latency Transport) communication among the cluster nodes, the interface cards on each node must use the same media speed settings. Also, the settings for switches or hubs used for the interconnects must match that of the interface cards. Incorrect settings can cause poor network performance or even network failure.

Guidelines for Auto-negotiation, media speed, and jumbo frame settings for LLT interconnects:

• If you have hubs or switches for LLT interconnects, we recommend using the Auto_Negotiation media speed setting on each Ethernet card on each node.
• If you have hubs or switches for LLT interconnects and you do not use the Auto_Negotiation media speed setting, set the hub or switch port to the same setting as that used for the cards on each node.
• If you use directly connected Ethernet links (using crossover cables), set the media speed to the highest value common to both cards, typically 100_Full_Duplex.
• Settings on Ethernet cards for jumbo frames must match that of the switches or hubs. Symantec does not recommend use of jumbo frames in an SF Oracle RAC environment.
• Symantec does not recommend using dissimilar network cards for private links.

Displaying and setting the Ethernet media speed

The following paragraphs describe displaying information about the current settings for interface cards and how to modify them if necessary.

 To display and set the Ethernet auto-negotiation setting and the media speed

1. Use the command ethtool <device_name> to display Ethernet card speed settings. For example:

   # ethtool eth2

   Check the displayed settings against the recommendations.

   See Auto-negotiation, media speed, and jumbo frame settings on private NICs.

2. The following examples show how to make changes to the settings:

   # ethtool -s eth2 autoneg on

   # ethtool -s eth2 speed 1000

   # ethtool -s eth2 duplex full

   Refer to the ethtool manual page for details