Patent ID: 8166094
Filing Date: 2012-04-24
Classification: G06F,G06Q

Abstract:
1. A process for transferring a cluster of computer systems from an online state to a partial quiesce state or a quiesce state, wherein said cluster includes a master system and a plurality of subordinate systems, each subordinate system may assume both an original state or a pending state, wherein the pending state is either the quiesce state or the partial quiesce state, and the original state is the online state, the process comprising: communicating from said master system to said plurality of subordinate systems being in said original state a first message requesting each of the systems to change from the original state to the pending state; preparing said plurality of subordinate systems to change from said original state to said pending state, said preparing includes: suspending all new input and output transactions with any client system of said plurality of subordinate systems, revoking data locks, waiting for clients to flush logs, flushing client's logs and suspending metadata disk I/O; wherein metadata is in a constant state, although client data is not; sending vote messages between said plurality of subordinate systems and said master system, each vote message includes a vote to either commit to changing within the cluster from said original state to said pending state or to abort; and in response to receipt of a commit vote message from at least one of said plurality of subordinate systems, changing the original state of said at least one of said plurality of subordinate systems within the cluster to said pending state including the quiesce state and the partial quiesce state, wherein the partial quiesce state includes all subordinate systems suspending all new transactions, waiting for clients to complete active transactions, flush client's logs, and suspend metadata disk I/O; wherein the quiesce state includes all subordinate systems suspending all new transactions, revoking all data locks, waiting for clients to complete active transactions, flushing client's logs, and suspending metadata disk I/O.