International Business Machines Corporation

Gabriel G Walder

Olympia Gluck

Yoram Novick

James C Chen

Danit Segev

Yigal Eisinger

Warren Keith Stanley

Theodore Timothy Harris, Jr

Edward Lin

Erez Webman

James Chien-Chiung Chen

Minh-Ngoc Le Huynh

William Henry Travis

David Brent Schreiber

Gilad Sharaby

Alex Chen

Lourdes Magally Gee

Richard Alan Schaeffer

Yelena Zilberstein

An apparatus, system, and method are provided for controlling link status changes across multiple independent control modules. The apparatus includes a copy services module configured to control multiple link adapters, each configured to establish multiple communication links between a source and a target storage device. The adapter transmits a link status change notification to the copy services module and starts a timer upon transmitting the link status change notification. The copy services module simultaneously processes link status change notifications from a plurality of communication links. The system includes a communications network and a plurality of storage devices having the above described apparatus. The method includes controlling a plurality of link adapters configured to establish multiple communication links between storage devices, transmitting a link status change notification, starting a timer upon transmitting the link status change notification, and simultaneously processing link status change notifications from a plurality of communication links.

Apparatus, system, and method for controlling link status changes

A method to provide information from a first information storage and retrieval system to a second information storage and retrieval system. Applicants' method provides a first information storage and retrieval system, where that first information storage and retrieval system comprises (N) PPRC adapters and information, and provides a second information storage and retrieval system. The method generates and saves an Established Path Bitmap which recites each of the (N) PPRC adapters, and generates an Available Path Bitmap. If a PPRC adapter is in communication with the secondary information storage and retrieval system, then the method adds that adapter to the Available Path Bitmap. The Established Path Bitmap and the Available Path Bitmap are used for subsequent PPRC operations.

Apparatus and method to provide information from a first information storage and retrieval system to a second information storage and retrieval system

A method for copying data over a network operating in accordance with a protocol, such as the ESCON protocol, that supports a given logical address range includes establishing a logical path over the network from a primary storage system to a secondary storage system using path logical addresses within the given logical address range. A virtual path is created over the logical path to carry the data from a source storage device in a first logical subsystem of the primary storage system to a target storage device in a second logical subsystem of the secondary storage system, wherein the first and second logical subsystems have respective first and second subsystem logical addresses which are outside the given logical address range. The virtual path is used in a peer-to-peer remote copy (PPRC) operation to copy the data from the source storage device to the target storage device.

Data communication with a protocol that supports a given logical address range

Methods, system and computer program product are provided to improve the efficiency of data transfers in a PPRC environment. A block of data to be transferred is divided into tracks. Each track is allocated to a data mover task control block (TCB) with a master TCB being assigned to supervise the data mover TCBs. The tracks are then transferred from the primary storage controller to the secondary controller in a piped fashion over a link coupling the primary and secondary storage controllers. However, the usage of resources is monitored by a resource management algorithm and, if too many TCBs are being used for a transfer or if the supply of data mover TCBs is exhausted, the transfer is automatically switched to a serial, non-piped transfer with the master TCB serving as the data mover TCB for the remaining tracks. In addition, the various links coupling the primary and secondary storage controllers is monitored to determine which link will provide the fastest transfer. If, during a transfer of tracks over one link, a faster link is identified, the transfer may be switched to the second, faster link.

Bandwidth utilization in a PPRC system

A method for data backup includes creating a sidefile in a cache memory of a data storage system. Entries are added to the sidefile specifying copy operations to be respectively performed by copy services in the system, including at least first and second copy services of different, first and second types. The copy operations specified by the operations are then executed using the first and second copy services.

Efficient data backup using a single side file

A method that uses a single callback function for a multiphase service with possible discontinuation of execution between the phases. The method is based on assignment of a case in the callback function for each phase or state of the service and a stack of state descriptors. At each call to the callback function, the top descriptor is popped off the stack and the appropriate case in the callback function is run.

Efficient thread programming using a single callback function

Growing community of inventors

K. Haim, Israel

Gabriel G Walder