Login to the command line shell and do a regular shutdown as follows:

 ~# poweroff

Do whatever maintenance is required.

You can simply turn the computer back on once it’s ready without causing any damage to the system installation.

Once it boots, if everything is ok, it will set itself as the secondary (spare) host.

If it boots as primary, that means there is some connection issue between hosts.

Next check the DRBD status:

 ~# cat /proc/drbd

DRBD should show the connected state as Secondary/Primary or the sync progress if it’s still synching with the primary. If it shows Primary/Unknown or Secondary/Unknown, there is most likely a connection issue. Shut down the server again, check all cables, etc. and turn it on again.

To switch it to primary again, enter the command line shell and send the SIGUSR1 signal to sysMONIT, as follows:

~# killall -SIGUSR1 sysmonit

This will tell sysMONIT to execute takeover action.