Which are the scenarios where the Mediator can trigger a site failover MAUSO?
Applies to
- MetroCluster IP
- Mediator
- Automatic Unplanned Switch Over (AUSO)
Answer
The following table describes the different disaster scenarios and corresponding actions taken for MAUSO:
Disaster Scenario | AUSO triggered? | Notes |
|
yes |
This condition will be detected about 15 seconds after the last node is down |
All the nodes panic at site A |
yes |
AUSO will be triggered soon after the last node panics. |
All nodes halted on site A |
no |
Nodes are expected to be started by the user. |
All nodes rebooted on site A |
no |
Nodes are expected to come up, no AUSO is triggered. |
A1 takes over A2 gracefully |
no |
|
A2 panicked |
yes |
Site B will use the mediator disks to establish quorum and trigger switchover |
Diaster at site A |
no |
Manual switchover will be required |
NvLog not in sync on site A |
no |
|
SFO is disabled on siteA A1 is down |
yes |
Site B will use the mediator disks to establish quorum and trigger switchover |
SFO is disabled at site B |
no |
DR-AUX mailbox is not available, hence AUSO cannot be performed. |
On node A1, both ISLs fail and mediator is not accessible |
no |
A1 is halted. A2 will takeover |
B2 is down, B1 in takeover. |
no |
|
A2 is down, A1 in takeover. |
no |
DR-AUX mailbox is not available, hence AUSO cannot be performed. |
SFO is disabled at site A and Site B |
no |
DR-AUX mailbox is not available, hence AUSO cannot be performed. |
|
no |
Nodes will stay alive. |
Site A isolated with both ISLs and mediator connection failure at the same time |
yes |
Site B will obtain the mediator lock and do switchover. Site A will commit suicide. |
Both ISLs failed on site A |
no |
AUSO is not possible due to loss of quorum. Nodes will stay online. |
Both ISLs failed on site A |
yes |
Site B will use the mediator to determine that site A is down and then initiate a switchover. |
Both ISLs failed on site A |
no |
AUSO not possible. Manual intervention required. |
Mediator is deleted |
no |
AUSO is not possible. Manual switchover will be required |
On node A1, mediator disk failed |
no |
|
Both site A nodes lose access to mediator, then disaster at site A |
no |
AUSO is disabled after mediator failure. AUSO won't happen after disaster |
Mediator disk failed on one or more site A nodes. |
yes |
AUSO will first be disabled. Then, after restoring mediator, AUSO will be automatically enabled. |
Additional Information