Abstract: A scale-out computing cluster may include a large number of computing servers and storage devices. In order to provide high reliability, the computing cluster must be able to handle failures of individual devices. Reliability of the computing cluster may be improved by providing a standby server for each active server in the computing cluster. If any active server fails, the corresponding standby server is activated. The failed server may be brought back online or replaced, at which time the restored server becomes the standby server for the now-active original standby server. During the restoration period, if any other active server fails, the standby server for that active server is immediately activated. As a result, the recovery ability of the computing cluster is only challenged if both servers of an active/standby pair fail during the restoration period, substantially improving reliability.

Abstract: A scale-out computing cluster may include a large number of computing servers and storage devices. In order to provide high reliability, the computing cluster must be able to handle failures of individual devices. Reliability of the computing cluster may be improved by providing a standby server for each active server in the computing cluster. If any active server fails, the corresponding standby server is activated. The failed server may be brought back online or replaced, at which time the restored server becomes the standby server for the now-active original standby server. During the restoration period, if any other active server fails, the standby server for that active server is immediately activated. As a result, the recovery ability of the computing cluster is only challenged if both servers of an active/standby pair fail during the restoration period, substantially improving reliability.

Abstract: A scale-out computing cluster may include a large number of computing servers and storage devices. In order to provide high reliability, the computing cluster must be able to handle failures of individual devices. Reliability of the computing cluster may be improved by providing a standby server for each active server in the computing cluster. If any active server fails, the corresponding standby server is activated. The failed server may be brought back online or replaced, at which time the restored server becomes the standby server for the now-active original standby server. During the restoration period, if any other active server fails, the standby server for that active server is immediately activated. As a result, the recovery ability of the computing cluster is only challenged if both servers of an active/standby pair fail during the restoration period, substantially improving reliability.

Abstract: A computer implemented method for initializing a first image of a first database from a recovery image; modifying the first image of the first database by replaying transaction logs of a second database; establishing a connection with a client; receiving a query via the connection, the query including a transaction to be executed on the first database; and rejecting the query when the transaction would cause any one of: updating of the first image of the first database; generating a new transaction log; and modifying the recovery image. Related apparatus, systems, techniques and articles are also described.

Abstract: A computer implemented method is provided. The method comprises initializing a first database image of a first database system based on a recovery image comprising committed transactions, visible uncommitted transactions, and undo logs associated with the visible uncommitted transactions, undoing the visible uncommitted transactions using the undo logs, generating redo logs from the undo logs, replaying the redo logs to create invisible uncommitted transactions, and after replaying the redo logs, replaying transaction logs received from a second database system. Related apparatus, systems, techniques and articles are also described.

Abstract: A computer implemented method for initializing a first image of a first database from a recovery image; modifying the first image of the first database by replaying transaction logs of a second database; establishing a connection with a client; receiving a query via the connection, the query including a transaction to be executed on the first database; and rejecting the query when the transaction would cause any one of: updating of the first image of the first database; generating a new transaction log; and modifying the recovery image. Related apparatus, systems, techniques and articles are also described.

Abstract: A computer implemented method is provided. The method comprises initializing a first database image of a first database system based on a recovery image comprising committed transactions, visible uncommitted transactions, and undo logs associated with the visible uncommitted transactions, undoing the visible uncommitted transactions using the undo logs, generating redo logs from the undo logs, replaying the redo logs to create invisible uncommitted transactions, and after replaying the redo logs, replaying transaction logs received from a second database system. Related apparatus, systems, techniques and articles are also described.