Fault-tolerance and Persistence in TIBCO ActiveSpaces
http://tibcoactivespacesonlinetraining.blogspot.com/2015/07/fault-tolerance-and-persistence.html
Fault-tolerance
and Persistence
If you are a seeder or replicator of the key for a get operation, it will be serviced at the very low latency “in-process” speed.
If you are a seeder or replicator of the key for a get operation, it will be serviced at the very low latency “in-process” speed.
If
the size of the dataset is small, you can even ensure that reads on ALL keys
will be at in-process speed if you set the replication count of the space to
ALL.
Replicate ALL (the numeric value used in configuration for REPLICATE_ALL is -1 ) is in general very useful for smaller data sets where data is read a lot more often than it is modified:
Replicate ALL (the numeric value used in configuration for REPLICATE_ALL is -1 ) is in general very useful for smaller data sets where data is read a lot more often than it is modified:
1. lookup data
2. joins
3. and so on
With asynchronous replication, the write request is sent to the seeder for the key (probably another process), and then synchronously acknowledged back to the process issuing the write while simultaneously being sent to the replicators asynchronously.
3. and so on
With asynchronous replication, the write request is sent to the seeder for the key (probably another process), and then synchronously acknowledged back to the process issuing the write while simultaneously being sent to the replicators asynchronously.
With
synchronous replication, the write request is sent to the seeder and all the
replicators with acknowledgement back to the process issuing the write.
Synchronous
replication does NOT mean that at the network level a single node sends the
replication requests to all of the other nodes, because replication happens in
a more distributed way in ActiveSpaces.
Persistence
is what provides you with the ability to shut down all of the seeders or the
entire Metaspace and then recover the data that was stored in the space when
the system went down:
- Shared-nothing persistence typically scales better than shared all persistence.
- Shared-nothing persistence extends the replication degree of the space:
However,
there is no “automated recovery” of spaces in shared-nothing persistence. You
must ensure that you have started enough of your processes doing seeding on the
space before administratively triggering the recovery.
Also
pay attention to the order in which the persisters were brought down if some
write operations occurred after some of the persisters went down.
