Best Practices for SGeRAC and Oracle RAC on HP-UX 11i, March 2009

Figure 3. Alternative configuration – multiple RAC databases

Timeouts

The SG-HB timeout (MEMBER_TIMEOUT) should be set based on service availability requirements.

Optionally if CSS-HB is changed, the CSS-HB timeout should be tuned to provide an opportunity for

Serviceguard to complete reconfiguration and update CSS through group membership service (GMS)

prior to CSS timeout. Optionally if RAC-DB-IC timeout is changed, RAC-DB-IC timeout should be 15

seconds above CSS-HB timeout. Note that the timeout relations are slightly different when using

Cluster Interconnect Subnet monitoring.

Subnet monitoring or Cluster Interconnect Subnet monitoring

Serviceguard packages can be configured with a subnet dependency on the RAC-DB2-IC. If both

LAN3 and LAN4 fail, the Serviceguard package can request halting the RAC instance where the

interconnect failure is detected. Serviceguard subnet monitoring has a limitation in that if all

interconnects fail (e.g. primary and standby switches failed at the same time), all instances are halted.

If there is a concern with simultaneous failure of both switches, Serviceguard supports multiple

standbys, so you can add additional standby switches if you are concerned about simultaneous

failure of both switches.

Without subnet monitoring, double networks failures on the RAC-DB2-IC network will be discovered

by IMR timeout and IMR determines which instance to evict.

Starting with A.11.18, SGeRAC introduced a new feature called Cluster Interconnect Subnet (CIS)

monitoring to address the limitation with subnet monitoring. The feature adds a new parameter

CLUSTER_INTERCONNECT_SUBNET for use with multi-node packages (MNP). When RAC instances

are configured with MNP packages and the RAC subnets are monitored using

CLUSTER_INTERCONNECT_SUBNET, if the monitored subnet fails, at least one MNP package will

remain.

Node A

LAN 1

Node B

RAC

DB2

Private

(primary)

Private

(standby)

Private

(primary)

LAN 1

LAN 2

CSS-HB

RAC-DB1-IC

Private

(standby)

LAN 2

LAN 4

LAN 3