Emc IP Holding Company LLC

Emc Corporation

Kevin Granlund

Edward S Robins

Stephen Richard Ives

Seema G Pai

Evgeny Malkevich

Roii Raz

Barak Bejerano

Steven T McClure

Dan Aharoni

Steven R Chalmer

Brett D Niver

Andrew Chanler

Prakash Venkatanarayanan

Hagay Dagan

Michael Garvey

Dale R Elliott

Charles E Arsenault

Sergey Rytenkov

Krishnamoorthy Anantharaman

David L Scheffey

Michael E Fields

A distributed network of storage elements (DNSE) is provided in which the physical capacity of each drive is split into a set of equal sized logical splits which are individually protected within the DNSE using separate RAID groups. To reduce restoration latency, members of the RAID groups having a member in common on a given drive are spread within the DNSE to minimize the number of sets of drives within the DNSE that have RAID members in common. By causing the splits to be protected by RAID groups, restoration of the splits may occur in parallel involving multiple drives within the DNSE. By minimizing the overlap between RAID members on various drives, failure of a given drive will not require multiple reads from another drive in the DNSE. Likewise, spare splits are distributed to enable write recovery to be performed in parallel on multiple drives within the DNSE.

Allocating RAID storage volumes across a distributed network of storage elements

Individual storage devices of a RAID group are monitored for faults. A health indicator for each storage device is calculated based on fault growth rate. Non-failed storage device are swapped out based on the health indicator. Techniques for monitoring the storage devices include background media scans and growth list polling.

RAID failure prevention

Described are techniques for selecting a storage pool configuration. A set of one or more candidate storage pool configurations is determined. For each of the candidate storage pool configurations of the set, a reliability calculation is performed to determine a reliability value indicating reliability of the candidate storage pool configuration. For each of the candidate storage pool configurations of the set, an availability calculation is performed to determine an availability value indicating availability of the candidate storage pool configuration. In accordance with selection criteria, one of the candidate storage pool configurations of the set for a first storage pool is selected. The selection criteria includes the availability value and the reliability value for each of the plurality of candidate storage pool configurations.

Techniques for reliability and availability assessment of data storage configurations

A data storage system employs a virtual disk enclosure that utilizes a number of physical disk drives to create a set of virtual disk drives that are visible to the remainder of the storage system. The virtual disk drives exhibit a set of characteristics such as respective storage capacities, access times, and reliability measures that are user-selectable within respective limits determined by the set of corresponding physical disk drive characteristics. For example, a RAID protection scheme can be used such that the overall storage capacity of the virtual disk drives is less than that of the physical disk drives, but has greater overall reliability/availability. The system may utilize a recursive protection scheme in which the virtual disk drives are utilized according to a second RAID configuration to provide a set of highly available logical storage volumes to host computer systems connected to the data storage system. The virtual disk enclosure preferably includes redundant components for enhanced system availability.

Data storage system employing virtual disk enclosure

Power supply slew time testing is performed on units that require a power supply for operation. A power supply voltage is applied to a unit under test. The power supply voltage has a test slew time that is selected to evaluate operation of the unit under test in a system. A response of the unit under test to the power supply having the test slew time is observed, and the condition of the unit under test is determined based on the response to the power supply having the test slew time. The test may involve application of the power supply voltage having a maximum test slew time and application of the power supply voltage having a minimum test slew time. The test slew times are selected based on the expected range of power supply slew times when the unit is installed in a system.

Power supply slew time testing of electronic circuits

Growing community of inventors

Sutton, MA, United States of America

Kevin Granlund