David S Meiri

US Patent:

6553464, Apr 22, 2003

Filed:

Mar 7, 2001

Appl. No.:

09/801252

Inventors:

Peter Kamvysselis - Boston MA
Dan Arnon - Boston MA
David Meiri - Boston MA
Mark J. Halstead - Waltham MA

Assignee:

EMC Corporation - Hopkinton MA

International Classification:

G06F 1516

US Classification:

711148, 709217, 709218, 709219, 709227, 709278, 709229, 711114, 711118, 711137, 711147, 711150

Abstract:

Providing data from a volume of a remote storage device coupled to a local storage device that is coupled to a host, includes providing a command to the remote storage device to request the data, if the data is stored in a cache portion of the remote storage device, the remote storage device providing the data, and if the data is not stored in the cache portion of the remote storage device, the remote storage device causing the data to be fetched from the volume and returning one of: a disconnect or an indicator that the data was not found. Causing the data to be fetched from the volume may include creating a separate wait task that waits for the data to be fetched from the volume. The separate wait task may be created only if there is not already another wait task waiting for the same data. The wait task may post an error if the data is not fetched after a predetermined amount of time, such as four seconds. An error may be posted if the data is not fetched after a predetermined amount of time, such as eight seconds.

US Patent:

6640280, Oct 28, 2003

Filed:

Jun 25, 2001

Appl. No.:

09/891110

Inventors:

Peter Kamvysselis - Boston MA
Dan Arnon - Boston MA
David Meiri - Boston MA
Mark J. Halstead - Waltham MA

Assignee:

EMC Corporation - Hopkinton MA

International Classification:

G06F 1208

US Classification:

711113

Abstract:

Providing data from a volume of a remote storage device coupled to a local storage device that is coupled to a host, includes providing a command to the remote storage device to request the data, if the data is stored in a cache portion of the remote storage device, the remote storage device providing the data, and if the data is not stored in the cache portion of the remote storage device, the remote storage device causing the data to be fetched from the volume and returning one of: a disconnect or an indicator that the data was not found. Causing the data to be fetched from the volume may include creating a separate wait task that waits for the data to be fetched from the volume. The separate wait task may be created only if there is not already another wait task waiting for the same data. The wait task may post an error if the data is not fetched after a predetermined amount of time, such as four seconds. An error may be posted if the data is not fetched after a predetermined amount of time, such as eight seconds.

US Patent:

6862632, Mar 1, 2005

Filed:

Nov 30, 2001

Appl. No.:

09/997810

Inventors:

Mark J. Halstead - Waltham MA, US
Dan Arnon - Boston MA, US
David Meiri - Boston MA, US

Assignee:

EMC Corporation - Hopkinton MA

International Classification:

G00F003/00
G06F012/00
G06F013/00

US Classification:

710 31, 710 32, 710 33, 710 36, 710 38, 710240, 710316, 711111, 711147, 711150, 711154, 711161, 711162, 707 10, 707201, 707202, 707203, 707204, 714 4, 714 6, 714 43, 714748, 714749, 714769, 709208, 709217, 709229, 713 2, 713100

Abstract:

Dynamically creating a communication path between first and second storage devices, includes creating a connection to a source volume on the first storage device and indicating that the source volume is not ready to transmit data on the communication path, after successfully creating the connection to the source volume, creating a connection to a destination volume on the second storage device and initially indicating that portions of one of: the destination volume and the source volume do not contain valid copies of data, where the destination volume accepts data from the source volume, and after successfully creating the connections to the source and destination volumes, indicating that the source volume is ready to transmit data on the communication path. Dynamically creating a communication path between first and second storage devices, may also include creating at least one of: the source volume and the destination volume. Creating the connection to the source volume may include modifying a table containing configuration information for the first storage device.

US Patent:

6883018, Apr 19, 2005

Filed:

Jan 24, 2001

Appl. No.:

09/768994

Inventors:

David Meiri - Boston MA, US
Dan Arnon - Boston MA, US
Mark J. Halstead - Waltham MA, US
Peter Kamvysselis - Boston MA, US

Assignee:

EMC Corporation - Hopkinton MA

International Classification:

G06F015/16

US Classification:

709205, 709201, 709206, 709207, 718106

Abstract:

A method for scanning a message-list accessible to a plurality of processors includes retrieving, from a cache associated with a scanning processor from the plurality of processors, information identifying a starting message-slot. This information is then used to begin a scan of the message-list at that starting message-slot. The information indicating the starting message-slot is obtained by identifying, in the message-list, a message-slot containing a message intended for a recipient processor from the plurality of processors and obtaining, from the identified message-slot, information indicative of a location of a succeeding message-slot in the message-list. This information is then cached, for retrieval during a subsequent scan of the message-list.

US Patent:

6886164, Apr 26, 2005

Filed:

May 8, 2001

Appl. No.:

09/851039

Inventors:

David Meiri - Boston MA, US

Assignee:

EMC Corporation - Hopkinton MA

International Classification:

G06F009/00

US Classification:

718104, 709226, 709229, 702179, 702186

Abstract:

A method for selecting a resource from a plurality of resources includes determining a score for that resource on the basis of a stochastic property of that resource. An interval corrsesponding to that resource is then defined to have an extent that depends on the score. A particular resource is then selected by generating a random number and selecting that resource when the random number falls within the interval.

US Patent:

6898685, May 24, 2005

Filed:

Mar 25, 2003

Appl. No.:

10/396786

Inventors:

David Meiri - Cambridge MA, US
Mark J. Halstead - Holliston MA, US
Haim Kopylovitz - Newton MA, US
Benjamin W. Yoder - Framingham MA, US
Adi Ofer - Wellesley MA, US
Hana Moreshet - Framingham MA, US

Assignee:

EMC Corporation - Hopkinton MA

International Classification:

G06F012/00

US Classification:

711167, 711162, 711112, 711111, 700 82, 707204, 714 6

Abstract:

Ordering data writes include a host computer providing a plurality of data writes to a primary storage device, the primary storage device assigning a first sequence number to data writes begun after a first time and before a second time, the primary storage device assigning a second sequence number, different from the first sequence number, to data writes begun after the second time, in response to completion of all writes assigned the first sequence number, the primary storage device transferring writes assigned the first sequence number to a secondary storage device, and, in response to the primary storage device transferring all writes assigned the first sequence number to the secondary storage device, the primary storage device sending a commit message to the secondary storage device. Ordering data writes may also include, in response to receiving a commit message from the primary storage device, the secondary storage device storing the data writes having the first sequence number.

US Patent:

6910075, Jun 21, 2005

Filed:

Oct 2, 2002

Appl. No.:

10/262684

Inventors:

Marik Marshak - Newton MA, US
Mark J. Halstead - Watertown MA, US
David Meiri - Cambridge MA, US
Alexandr Veprinsky - Brookline MA, US

Assignee:

EMC Corporation - Hopkinton MA

International Classification:

G06F015/16

US Classification:

709227, 709201, 709205, 709216, 709217, 709219, 709220, 709243, 370352, 370398, 370469, 707201, 707202, 710 1, 712 13, 714 6, 718104

Abstract:

Described are techniques used in dynamically modifying RDF groups. A system call is issued by a host computer system to execute a remote system call on a first data storage system to create, remove, or modify an RDF group between the first data storage system and another data storage system that is remotely connected to the first data storage system in an RDF switched environment. As part of executing the remote system call, data is pushed from the first to the second data storage systems without having an established link between the data storage systems. Each data storage system performs processing to make the necessary modifications in all directors in accordance with the dynamic RDF group. A status indicating success or failure of the remote system call is returned to the host computer system.

US Patent:

6938122, Aug 30, 2005

Filed:

Jan 23, 2001

Appl. No.:

09/767773

Inventors:

David Meiri - Boston MA, US
Dan Arnon - Boston MA, US
Mark J. Halstead - Waltham MA, US
Peter Kamvysselis - Boston MA, US

Assignee:

EMC Corporation - Hopkinton MA

International Classification:

G06F013/14

US Classification:

711114, 709218

Abstract:

A mechanism to support remote mirroring of storage devices by data storage systems in a one-to-many switched environment. Each data storage system includes a disk director that is adapted to control at least one device group that is supported in a mirrored configuration with a corresponding device group controlled by one of the other data storage systems. For each device group and corresponding device group, there are first ports associated with the device group and second ports associated with the corresponding device group. A switch element is adapted to connect one of the first ports to at least one of the second ports so that data may be exchanged between the ports for each device group and corresponding device group. The disk director selects which first port is to be connected to which second port via the switch element in the establishment of a logical link. Thus, each port connected to the switch is capable of achieving multiple connections to multiple destinations for increased connectivity, redundancy and performance (load balance) without additional hardware.