05-14-2014 08:16 AM
during a hpvmmigration there is a phase called the frozen zone. Is there a rule to calculate the expacted time for this frozen zone ? What are the dependencies for the lenght of the frozen zone ?
Reason for that: we have a cluster running on HPvms and from time to time the frozen zone exceeds the cluster member timeout. So what would be a good value to calculate that timer to avoid cluster crashes during online migration?
05-14-2014 01:09 PM
The value is hard to estimate as it depends not just on the configuration (number of NPIV interfaces, memory size,
network connectivity), but also on the runtime factors (amount of currently hot memory, how quickly SAN responds
to stopping and bringing up NPIV on the other side, the current network transfer performance etc.).
Exactly for this reason you should think of removing the node from cluster at least for the OVMM duration. It seems the manual doesn't explicitly say that, but reading between these lines in HPVM Admin guide makes it obvious that online migration of a guest running SG is not a good idea:
Use the hpvmmodify -x online_migration=disabled option to prevent a particular virtual
machine from migrating online. This is especially important if the guest is running software that is
sensitive to external network monitoring with short timing intervals, such as Serviceguard.