Emc Corporation

Emc IP Holding Company LLC

Alexander Veprinsky

Arieh Don

Marik Marshak

Ian Wigmore

Stephen Smaldone

John T Fitzgerald

Jonathan I Krasner

Patrick Brian Riordan

Yechiel Yochai

Philip E Tamer

Robin Budd

James L Davidson

A system for resolving write pressure includes a primary storage unit, a backup storage unit, and a processor. The primary storage unit comprises a primary storage unit input buffer and a volume storage unit. The backup storage unit comprises a backup storage unit input buffer and a volume backup storage unit. The processor is to: store a first set of input data in the backup storage unit input buffer in the event that the primary storage unit input buffer is unable to store the first set of input data and transfer the first set of input data to the primary storage unit input buffer as space is available after storing data from the primary storage unit input buffer in the volume storage unit.

Resolving write pressure using existing backup appliance as additional primary storage

Described are techniques for servicing data requests in a data storage system. One or more data requests from an application executing on the host are received. The data storage system allocates a first amount of resources for use in servicing data requests from the application. Behavior of the host is monitored for occurrences of I/O failure. In accordance with criteria and the occurrences of I/O failure, it is determined whether at least one of the host or the application is in a state of pending failure. If it is determined that at least one of the host or the application is in a state of pending failure, a second amount of resources larger than the first amount are allocated for a time period when servicing data requests from the application. After the time period, data requests from the application are serviced in accordance with the first amount of resources.

Techniques for adjusting priorities associated with servicing requests

Described are techniques used in detection of a data corruption in a computer system in connection with read and write operations. For a write operation, a host issues a write request that includes a checksum value determined in accordance with data associated with the write request. The write request is received by a data storage system that performs data validation using the checksum. The host issues a vendor-defined write request operation that includes the checksum as a data field in the request packet sent to the data storage system. For a read operation, a host issues a read request and the data storage system determines a checksum value before servicing the read request. The checksum is validated at the top of the I/O stack on the host by the file system filter driver.

End-to-end checksumming for read operations

Described are techniques in connection with restricting access to devices within a computer system. Access to a device may be restricted to one or more particular hosts within the computer system, and also further restricted to a particular software program executing within the particular hosts. The restricted access device (RAD) may be recognized by one or more hosts only having access to specific portions of the RAD unless special RAD I/O opcodes are used in connection with performing I/O operations. Access to a device may be obtained by enabling a particular use of the special RAD I/O opcodes. Subsequently, access to the same device may be disabled by stopping use of the special RAD I/O opcodes by a particular host and/or software executing in the host. RADs may be used in a variety of applications including, for example, restricting access to shared logs or journals and protecting a database.

Restricted access devices

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Brookline, MA, United States of America

Alexander Veprinsky