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
Add-on cards, the slots they are mounted in, and the number, size, and RAID configuration of local disks, must be the same.
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.
For PRIMERGY Partition Model servers, the number of system boards and the I/O count should be the same as those of the primary server.
BIOS settings
The same settings must be used for the primary and spare servers. Refer to "BIOS Settings for Managed Servers" in "3.5 Configuring the Server Environment" for details.
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.
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" 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 PRIMERGY Partition Models, if a spare server is configured as the Reserved SB of another partition, switchover might not operate correctly when server switchover and reserved SB switchover are conducted at the same time.
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 a physical OS and a VM guest (using the high-availability feature provided with its server virtualization software), there must be no VM guests on the spare server.
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.
The selected active server or spare server has not been placed into hardware maintenance mode (For PRIMERGY Partition Model servers).
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.
The selected active server or spare server has not been placed into hardware maintenance mode (For PRIMERGY Partition Model servers).
