The following conditions must be satisfied for manual server switchover, failback, and Auto-Recovery to function correctly.
Conditions for Spare Servers
The spare server must be identical to the active server in the ways listed below.
If these conditions are not satisfied, allocation of a spare server may not be possible, server switchover may fail, or the server may malfunction after the switchover is completed.
Server model
Server hardware configuration
The following settings for optional cards and expansion boards must be the same.
The locations they are mounted in
The number and sizes of local disks
RAID settings
There are no other hardware conditions for the spare server (such as memory capacity, number of CPUs and CPU clock speed). However, the hardware configuration of the spare server must be capable of running the operating system and applications running on the primary server.
BIOS settings
The same BIOS settings must have been made for all servers according to the procedure in "BIOS Settings for Managed Servers" in "3.5 Configuring the Server Environment".
OBP settings
For SPARC Enterprise, the OBP settings to start automatically from SAN servers of the same target disk must have been made according to the procedure in "OBP (Open Boot Prom) Settings (SPARC Enterprise)" in "3.5 Configuring the Server Environment".
With the storage affinity switchover method, as setting changes are only performed for Fibre Channel switch storage devices, it is necessary to perform configuration of servers that will be changed during switchover, and HBA and OBP settings.
LAN and SAN access scope
The spare server must use the same network redundancy method, have the same redundancy paths, and have access to the same network and storage devices. Note that LAN or fibre channel switches connected in a cascade configuration are viewed as a single device.
Firewall
There must be no firewall between the primary server and the spare server.
Subnet
For servers other than blade servers, the primary server and the spare server must belong to the same subnet.
If a spare server is shared by a physical OS and one or more VM guests (using the high-availability feature provided with their server virtualization software), the spare server must be configured for SAN boot using I/O virtualization.
For details, refer to "Figure 9.3 Sharing a Spare Server Between Physical OS's and VM Guests (High-availability Function of Server Virtualization Software)" in "9.2 Configuration".
When using a server on which a server OS is operating as a spare server, both the primary server and spare server should be in a configuration that uses I/O virtualization.
For details, refer to "Figure 9.4 Configuration Using a Server on which a Server OS is Operating as a Spare Server" in "9.2 Configuration".
Also, if more than two local disks are connected to a spare server in a backup/restore configuration, and if the partitioning of the disks coming after the first in the boot order is different than the first disk, a warning message may be displayed at restart, or the operating system may not restart, causing any switchovers initiated to fail. After configuring the spare server, verify that it is operating properly by performing a switchover and failback.
If the operation fails, configure the partitions other than the first boot disk of the spare server to match the configuration of the primary server, or set up the primary server configuration so that it does not depend on any disk other than the first, using automatic service startups and re-labeling the Windows drives as necessary.
With blade servers, if the primary server and spare server do not belong to the same subnet, if server switchover is performed to the spare server it is necessary that the VLAN ID or port group settings of the internal LAN switch ports are adjusted automatically.
For the setting method, refer to "9.6 Server Switchover Settings".
Conditions for Server Switchover
The following conditions must be satisfied for a server switchover or Auto-Recovery to succeed:
The server configuration cannot already be switched over (the primary server must be the active server).
The status of the spare server must be "normal", "warning" or "stop". If a VM host has been installed on the spare server(for VMware HA), its status must be either "normal" or "warning".
If a spare server is shared by more than one active server, none of the other primary servers may be switched over to that spare server.
If the server is in a local boot environment, its system image must have been backed up.
Conditions for Server Failback
The following conditions must be satisfied for server failback to succeed:
The active server must have been switched over to the spare server.
The status of the primary server must be "stop".
If the server is in a local boot environment, its system image must have been backed up.
