Improving the Performance of Stratus Cloud Availability Services

To improve the performance of Stratus Cloud Availability Services, you can optionally make the following changes to your KVM-FT pair groups. The changes include:

• Enabling jumbo frames on each KVM-FT compute node in an FT pair group and the Ethernet switch that connects them.

  Change the maximum transmission unit (MTU) from the default of 1500 bytes of payload to the maximum of 9000 bytes. Setting this maximum packet size increases network efficiency by reducing the overall number of packets that each contain networking protocol overhead. (If you want to enable jumbo frames, you must change this setting on each KVM-FT compute and Ethernet switch before the new setting will take effect.)

• Changing a BIOS setting on each KVM-FT compute node to disable the CPU power saving feature and increase CPU performance.

To improve the performance of Availability Services:

1. Log on to the management utility for the Ethernet switch that connects the A-links from your KVM-FT compute nodes. Enable jumbo frames on the switch by setting the MTU size to 9000 bytes. If needed, restart the Ethernet switch to enable the new setting. See the documentation for your Ethernet switch for more information.

2. Log on to the console of the first KVM-FT compute node as the root user, or be prepared to use sudo to run commands as root.

3. Switch to the /etc/sysconfig/network-scripts directory:

   # cd /etc/sysconfig/network-scripts

4. List the files in the network-scripts directory to display the ifcfg-device network startup files (for example, ifcfg-eth2). Locate the two ifcfg-device startup files that represent the A-link network interfaces for the compute node.

5. Update the network startup file for each A-link network interface in the compute node to set the MTU value to 9000 bytes. Modify each file as follows:
   1. Open the /etc/sysconfig/network-scripts/ifcfg-devname startup file in a text editor.

   2. If the MTU property is already present, change the MTU value to 9000 bytes; otherwise, add a new MTU=9000 line at the bottom of the file. For example:

      DEVICE=eth2
      HWADDR=A0:36:9F:2A:BD:3C
      TYPE=Ethernet
      ONBOOT=yes
      NM_CONTROLLED=no
      BOOTPROTO=none
      MTU=9000

   3. Save and close the network startup file.

   4. Repeat step 4 for the second A-link network interface in the compute node.

6. To apply the network startup changes, restart the compute node, as follows:

   # shutdown -r now

   Caution: Restarting the system or network disrupts any running instances.
   Note: Before the operating system starts again, be prepared to press the appropriate key combination to open the system BIOS setup utility.

7. In the system BIOS setup utility for the compute node, locate the Power Management properties. If possible, locate a property that controls CPU power and performance. Typically, the default setting throttles CPU performance to save energy. To improve the performance of the KVM-FT compute node, change the value of the property to maximize performance.

   BIOS properties vary by manufacturer and model. See the documentation for your system to locate the correct power-saving property, if present.

8. Save the changes in the BIOS setup utility and restart the compute node.

9. When the operating system starts, log on to the console of the compute node and display the status of each A-link network interface. Verify that the MTU value is set to 9000. For example, to verify the MTU value for eth2, execute the following command:

   # ifconfig eth2
   eth2   Link encap:Ethernet  HWaddr A0:36:9F:2A:BD:3C
   inet addr:10.200.11.50  Bcast:10.200.11.255  Mask:255.255.255.0
   inet6 addr: fe80::225:90ff:fed9:70aa/64 Scope:Link
   UP BROADCAST RUNNING MULTICAST  MTU:9000  Metric:1
   RX packets:3209 errors:0 dropped:0 overruns:0 frame:0
   TX packets:6 errors:0 dropped:0 overruns:0 carrier:0
   collisions:0 txqueuelen:0
   RX bytes:147614 (144.1 KiB)  TX bytes:468 (468.0 b)

10. Repeat the preceding steps on additional KVM-FT compute nodes and Ethernet switches, as needed. Set the same MTU size on both A-links in each KVM-FT compute node of an FT pair group.