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node freeze v/s service group freeze

allaboutunix
Level 6

Hi Team,

 

I came across a DIMM replacement activity in one of our solars servers which are in cluster.

Please assist before proceeding for teh activity shall i have to freeze teh service group OR DO i need to freeze the node?

ALso, kindly guide the scenario, when we should have to proceed for freezing the SG or freezing the node?

 

Thanks..

1 ACCEPTED SOLUTION

Accepted Solutions

Sunil_Yadav
Level 4
Employee

For DIMM replacement activity, node freeze (“hasys –freeze”) will be more appropriate. You can also use “hasys –freeze –evacuate” to switchover active service groups on peer systems in cluster. -evacuate option specifies that all groups are switched before the system is frozen; if no other system is available for a service group, it is taken offline.

Please find details of Group & System freeze, and their use cases too.

Group Freeze : Group is frozen using "hagrp -freeze" command. Freezing a service group prevents VCS from taking any action when the service group or a system faults. Freezing a service group prevents it from failing over to another system. The freezing process stops all online and offline procedures on the service group. Note that you cannot freeze a service group when the service group state is in transition. The -persistent flag indicates the freeze is maintained after a system is rebooted, or the engine is stopped and restarted. Note that if the service group is in ONLINE state and if you freeze the service group, then the group continues to remain in ONLINE state. Freezing a service group prevents dependent resources from going offline when a resource faults. It also prevents the Clean function from being called on a resource fault.

Usecase: You can freeze a service group when performing operations on its resources from outside VCS control. This prevents VCS from taking actions on resources while your operations are on. For example, freeze a database group when using database controls to stop and start a database. It can be useful while performing maintenance activity on the application(or group).

System Freeze : System is frozen using "hasys -freeze" command. Freezing a system prevents service groups from coming online on the system. When a system is frozen, no group configured on the frozen system can come online, whether manually, by failover, or by switching until the system is thawed with the -unfreeze option. Using the -persistent option specifies that the system remains frozen after VCS has been stopped and restarted. Groups online on the frozen system can be taken offline manually, by failover, or by being switched to another system. Using the -evacuate option specifies that all groups are switched before the system is frozen; if no other system is available for a service group, it is taken offline. Groups running on other systems do not fail over to a frozen system.

Usecase: It can be useful while performing maintenance activity on the system.

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1 REPLY 1

Sunil_Yadav
Level 4
Employee

For DIMM replacement activity, node freeze (“hasys –freeze”) will be more appropriate. You can also use “hasys –freeze –evacuate” to switchover active service groups on peer systems in cluster. -evacuate option specifies that all groups are switched before the system is frozen; if no other system is available for a service group, it is taken offline.

Please find details of Group & System freeze, and their use cases too.

Group Freeze : Group is frozen using "hagrp -freeze" command. Freezing a service group prevents VCS from taking any action when the service group or a system faults. Freezing a service group prevents it from failing over to another system. The freezing process stops all online and offline procedures on the service group. Note that you cannot freeze a service group when the service group state is in transition. The -persistent flag indicates the freeze is maintained after a system is rebooted, or the engine is stopped and restarted. Note that if the service group is in ONLINE state and if you freeze the service group, then the group continues to remain in ONLINE state. Freezing a service group prevents dependent resources from going offline when a resource faults. It also prevents the Clean function from being called on a resource fault.

Usecase: You can freeze a service group when performing operations on its resources from outside VCS control. This prevents VCS from taking actions on resources while your operations are on. For example, freeze a database group when using database controls to stop and start a database. It can be useful while performing maintenance activity on the application(or group).

System Freeze : System is frozen using "hasys -freeze" command. Freezing a system prevents service groups from coming online on the system. When a system is frozen, no group configured on the frozen system can come online, whether manually, by failover, or by switching until the system is thawed with the -unfreeze option. Using the -persistent option specifies that the system remains frozen after VCS has been stopped and restarted. Groups online on the frozen system can be taken offline manually, by failover, or by being switched to another system. Using the -evacuate option specifies that all groups are switched before the system is frozen; if no other system is available for a service group, it is taken offline. Groups running on other systems do not fail over to a frozen system.

Usecase: It can be useful while performing maintenance activity on the system.

View solution in original post