Switching Over and Switching Back › Setting High Availability Properties › Understanding High Availability Properties › Is Alive

Is Alive

Arcserve RHA continuously checks to see if the active host is up (according to Send ping request, Connect to DB, or User-Defined Script method, see below). These checks are made in scheduled intervals according to the Heartbeat Frequency.

Checking the status is interpreted as follows:

• If there is an indication that the active computer is OK (alive), no new action is taken, and the system continues to check according to the scheduled intervals of the Heartbeat Frequency.
• If there is an indication that the active computer is not OK (is not alive), the active computer is checked again at the next Heartbeat timeout for a maximum period of the Is Alive timeout. If no indication of the active host being alive is found within the Is Alive timeout, Arcserve RHA executes event notification. Simultaneously, it checks whether or not to perform a switchover, as defined by the Perform switchover automatically property.

Important! When using scripts, each script must reside in the same path and with the same name on both the Master and the Replica.

Is Alive Timeout (sec)

If the standby host does not receive indication that the active host is alive during this interval (in seconds), switchover or notification is initiated. The checks are performed at the Heartbeat Frequency.

Default is 300 seconds.

Heartbeat Frequency (sec)

Interval (in seconds) for sending heartbeat requests (performing the checks below).

Default is 30 seconds.

Check Method

Send Ping Request

ICMP requests are sent automatically from the standby host to the active host, to check if the active host is up.

The available options depend on the value of the Move IP property. For more information, refer to Redirection properties.

• If Move IP is On
• During the switchover, the IP is moved from the active computer to the standby. Therefore, the standby computer must check this IP continuously.

  In the IP for Ping property, enter IP Address to ping.

• If Move IP is Off

  During the switchover, the IP is not moved from the active to the standby computer. Therefore, define two IPs for ping:

  IP for ping from Master to Replica
  Enter IP address to ping. When the Replica computer is the active host, an ICMP request is made from the Master to the Replica. If no reply is received within two seconds, the Replica computer is considered non-operational.

  IP for ping from Replica to Master
  Enter IP address to send ping to. When the Master computer is the active host, an ICMP request is made from the Replica to the Master. If no reply is received within 2 seconds, then the Master computer is considered to be non-operational.

Connect to DB

[For database applications only] When this property is set to On, Arcserve RHA connects to the active computer's database according to the Heartbeat Frequency, and checks to see if the database services are running and all databases are mounted.

User-Defined Scripts

Allows the standard check methods to be augmented or replaced by user-defined actions in scripts.

Check Script on Active Host

This script runs on the active server, and checks if it is alive.

• Script Name

Enter the name and full path of script to run. Arcserve RHA connects to the active computer once every Heartbeat timeout, and executes the script. If the return value equals zero, the active computer is OK (alive). If the return value is different than zero, the active server is not responding and switchover is required.

• Arguments

  Arguments to be passed to the script specified in the previous property. Argument values must be static.

Check script on Standby host

This script runs on the standby server, and checks if the active server it is alive.

• Script Name

  Enter name and full path of script to be run. Arcserve RHA connects to the active computer once every Heartbeat timeout, and executes the script. If the return value equals zero, the active computer is OK (alive). If the return value is different than zero, the active server is not responding and switchover is required.

• Arguments

  Arguments to be passed to the script specified in the previous property. Argument values must be static.