Abstract: When a data write request is received from a request source, a storage controller stores write request data in a first volatile storage device, stores a log corresponding to the stored data in a non-volatile storage device, sends a completion response to the request source after storing the log, moves the data stored in the first volatile storage device to a second volatile storage device when no cache hit occurs for the data stored in the first volatile storage device over a first period from a first time when the data is stored in the first volatile storage device, and destages the data stored in the second volatile storage device to the non-volatile storage device when no cache hit occurs for the data stored in the second volatile storage device over a second period from a second time when the data is stored in the second volatile storage device.

Abstract: In a write process involving multiple storage nodes, each node contains a data storage area based on non-volatile storage devices. When updated data forming a stripe is written, two or more pieces of the data are distributed across different storage nodes. One node is responsible for assigning a sequence number to each piece of data. This sequence number, updated according to the writing state, serves as a reference for the order and status of the write operation. If power is unexpectedly lost and later restored, the storage node uses these sequence numbers to identify which data was being updated when the failure occurred. By comparing the sequence numbers of the different pieces of the stripe, the system can specify the correct update target. It then determines whether recovery should rely on the most recent updated data or revert to the previous non-updated version, thereby ensuring data accuracy and consistency after recovery.

Abstract: To provide a storage system including: a non-volatile storage device; a storage controller configured to process reading and writing of data and to input and output the data to and from the storage device; and a volatile memory, in which the storage controller selectively executes a write-back operation and a write-through operation, common order guarantee information is assigned to a cache data log in the write-back operation and data related to a write request in the write-through operation, and the cache data log in the memory is recovered using the order guarantee information when recovering from power interruption.

Abstract: When execution of a write-back operation is selected, a storage system stores, in a cache area, data for which a write request is issued from a higher-level apparatus, stores an updated content of the cache area in a cache log storage area, and then writes the data to a data storage area. On the other hand, when execution of a write-through operation is selected, the storage system does not execute storage into the cache area and the cache log storage area, stores an updated content of the data storage area in a write log storage area, and then writes the data to the data storage area.

Abstract: When performing an operation, a processor creates a log according to an update content updated by the operation, stores the created log in a memory, and stores the log stored in the memory in a drive and non-volatilizes the log. The log is divided into a first log and a second log according to a type of the log, and the first log is divided into a plurality of groups. When processing the log, the processor processes the first log and the second log in a predetermined order, processes the first log in the groups in a predetermined order determined in the groups, and processes the first log in parallel between the groups.

Abstract: A storage system provides balance to the performance of a distributed rebuild system and to the performance of a read local system in SDS. A storage controller in an active state and a storage controller in a standby state that takes over a process of the storage controller in the active state through failover are provided. The storage controllers are arranged in different nodes, form a redundancy group in which redundant data is distributed and stored. The storage system stores, in a storage device of the same node, user data input and output by the storage controller in the active state and stores redundant data of the user data in storage devices of a plurality of nodes different from the user data. The storage controller in the standby state changes to the active state and uses the redundant data to input and output data in the failover.

Abstract: A plurality of storage nodes constituting a first node group across a plurality of fault domains in a cloud environment are provided. For each node, a domain ID of a fault domain in which the node is generated is acquired, and a second node group is configured as a first node group from a necessary number of nodes whose domain IDs do not overlap as much as possible. The number of member nodes existing in the same fault domain in the second node group is equal to or less than the redundancy. The redundancy is the maximum number of member nodes allowed to stop simultaneously in the second node group. In the first node group, a node other than the second node group is a spare node that may be selected as a failback destination node.

Abstract: An object of the present invention is to increase the efficiency of writing of a data assurance code. A storage system includes: a processor; and a memory, and atomic write which assures data before update during update write of data can be executed. In the storage system, the processor determines whether the atomic write is applied or not on the basis of a write parameter of a data assurance code of user data which is to be subjected to update write, and in the case where it is determined that the atomic write is applied, executes update write of the data assurance code using the atomic write, and in the case where it is determined that the atomic write is not applied, writes log data including a copy of the data assurance code and, after that, executes write of the data assurance code.

Abstract: In a management node that manages a path between a primary storage system and a secondary storage system in a computer system, the secondary storage system includes a first node having a first SCS that processes copying in a unit of copy and a second node having a second SCS that performs a copy process in place of the first SCS when a failure occurs in the first SCS, the management node includes a processor, and the processor calculates a necessary number of paths, which is the number of paths necessary for a performance requirement, on the basis of quality of a network between the primary storage system and the secondary storage system and the performance requirement related to a communication amount necessary for copying in a unit of copy, and sets the necessary number or more of paths between the primary storage system and the first node.

Abstract: When execution of a write-back operation is selected, a storage system stores, in a cache area, data for which a write request is issued from a higher-level apparatus, stores an updated content of the cache area in a cache log storage area, and then writes the data to a data storage area. On the other hand, when execution of a write-through operation is selected, the storage system does not execute storage into the cache area and the cache log storage area, stores an updated content of the data storage area in a write log storage area, and then writes the data to the data storage area.

Abstract: A storage system includes one or more storage nodes each having a non-volatile storage device, a storage controller, and a volatile memory, in which the storage device includes a plurality of base image storage areas including at least a first base image storage area and a second base image storage area as areas for storing entire predetermined information stored in the memory as a base image, and the storage controller starts processing to store a next base image in the second base image storage area when the base image storage with respect to the first base image storage area is complete, and reads out the storage-completed base image and restores the image to the memory in a case where the predetermined information is lost from the memory.

Abstract: A volume to be accessed by a host is provided. A reliability policy related to data reliability and a performance policy related to response performance to an access to the volume are set in the volume. A node that processes redundant data of data for a node that processes the data related to the volume is determined based on the reliability policy. The determined node returns a result of an access to the volume from the host according to the performance policy.

Abstract: In each node constituting a storage system, there is at least one of a storage area (user area) in which a user data set is stored and a storage area (parity area). For the node having the user area, there is user part difference information including information indicating whether or not to be in presence of difference for each user area of the node. For the node having the parity area, there is parity part difference information including the information indicating whether or not to be in the presence of difference for each parity area of the node. Out of the parity part difference information, the information corresponding to the parity area is the information indicating the presence of difference when there is the information indicating the presence of difference in the storage area of any of the data sets used for generating the parity stored in the parity area.

Abstract: A storage system includes one or more storage nodes each having a non-volatile storage device, a storage controller, and a volatile memory, in which the storage device includes a plurality of base image storage areas including at least a first base image storage area and a second base image storage area as areas for storing entire predetermined information stored in the memory as a base image, and the storage controller starts processing to store a next base image in the second base image storage area when the base image storage with respect to the first base image storage area is complete, and reads out the storage-completed base image and restores the image to the memory in a case where the predetermined information is lost from the memory.

Abstract: A volume to be accessed by a host is provided. A reliability policy related to data reliability and a performance policy related to response performance to an access to the volume are set in the volume. A node that processes redundant data of data for a node that processes the data related to the volume is determined based on the reliability policy. The determined node returns a result of an access to the volume from the host according to the performance policy.

Abstract: In each node constituting a storage system, there is at least one of a storage area (user area) in which a user data set is stored and a storage area (parity area). For the node having the user area, there is user part difference information including information indicating whether or not to be in presence of difference for each user area of the node. For the node having the parity area, there is parity part difference information including the information indicating whether or not to be in the presence of difference for each parity area of the node. Out of the parity part difference information, the information corresponding to the parity area is the information indicating the presence of difference when there is the information indicating the presence of difference in the storage area of any of the data sets used for generating the parity stored in the parity area.

Abstract: A managing node includes a processor and a storage unit. A processor rearranges virtual machines arranged in managed nodes with high usage rates to other managed nodes based on a standard deviation of the usage rate of a CPU in a plurality of managed nodes, and selects the managed nodes in which many images of operating systems used by the virtual machine are stored, arranges the virtual machine, and starts up the virtual machine when a client starts up the virtual machine.

Abstract: Disclosed are power generation apparatuses. An exemplary power generation apparatus (1) is configured such that water vapor generated in a steam generator (2) is supplied to a scroll expander (3) to drive the scroll expander, wherein: a condensation device (5) is arranged in a discharge path (12) downstream of the scroll expander, the condensation device being configured to mix water vapor having passed through the scroll expander directly with cooling water to condense the water vapor; and the condensation device includes a control unit (10) that performs a control of adjusting the amount of cooling water supply so as to obtain condensed water having a predetermined temperature.

Abstract: Disclosed are power generation apparatuses. An exemplary power generation apparatus (1) is configured such that water vapor generated in a steam generator (2) is supplied to a scroll expander (3) to drive the scroll expander, wherein: a condensation device (5) is arranged in a discharge path (12) downstream of the scroll expander, the condensation device being configured to mix water vapor having passed through the scroll expander directly with cooling water to condense the water vapor; and the condensation device includes a control unit (10) that performs a control of adjusting the amount of cooling water supply so as to obtain condensed water having a predetermined temperature.

Abstract: A waste heat recovery system for a vessel for supplying to a plurality of scroll expanders which are connected in parallel to one another, steam generated by a heat exchanger using waste heat from a main machine as a heat source, may include gate valves corresponding to respective scroll expanders and an electronic controller which controls the number of the scroll expanders which drives based on flow volume of the steam by opening or closing of the gate valves.