Can these database replicas be made writeable if in case the actual database fails?
amolakn
@mpcomplete I'd think that would be the case, right? When one database fails (the main database), a backup one would be assigned as the new main database hence just made writeable. However as mentioned on later slides I can imagine the issue of coherency and accuracy of the databases when this happens.
bob_sacamano
Sometimes, you would have replicas of databases running in "hot-standby" mode - wherein all the operations are mirrored into the backup database while it's not servicing the frontend. When of the replicas die this standby node can be "seamlessly" brought in. This comes with the cost of buying more resource and having lower overall utilization. The common choice is to recover the database's state using checkpoints and logs that are cheap to generate and maintain.
Can these database replicas be made writeable if in case the actual database fails?
@mpcomplete I'd think that would be the case, right? When one database fails (the main database), a backup one would be assigned as the new main database hence just made writeable. However as mentioned on later slides I can imagine the issue of coherency and accuracy of the databases when this happens.
Sometimes, you would have replicas of databases running in "hot-standby" mode - wherein all the operations are mirrored into the backup database while it's not servicing the frontend. When of the replicas die this standby node can be "seamlessly" brought in. This comes with the cost of buying more resource and having lower overall utilization. The common choice is to recover the database's state using checkpoints and logs that are cheap to generate and maintain.