Emc IP Holding Company LLC

Emc Corporation

Igor Fradkin

Arieh Don

Scott Rowlands

John T Fitzgerald

Magnus E Bjornsson

Alan Rajapa

Alexandr Veprinsky

Erik P Smith

Alex Veprinsky

James L Davidson

Ramprasad Shetty

David Brown

Bandwidth consumption for IO paths between a storage system and host may be managed. It may be determined whether there is congestion on a front-end port (FEP) link. For example, the storage system may monitor for a notification from the switch in accordance with a Fibre Channel (FC) protocol. If a notification is received indicating congestion on an FEP link, the bandwidth thresholds (BWTs) for one or more IO paths between the storage system and one or more hosts that include the FEP link may be reduced. The host port BWTs may continue to be reduced until a congestion notification communication has not been received for a predetermined amount of time, in response to which the host port BWTs for one or more host port links on IO paths that include the FEP link may be increased. Similar techniques may be employed for an FEP link determined to be faulty.

Managing IO path bandwidth

Embodiments of the present disclosure relate to traffic class management of NVMe (non-volatile memory express) traffic. One or more virtual controllers for at least one host adapter (HA) of a storage device are generated. Each virtual controller is assigned a unique controller identifier (ID) Additionally, one or more input/output (IO) queues for each virtual controller are established. Further, IO workloads are processed via each IO queue.

Hardware virtualization

Techniques for transmitting data may include: statically allocating a first buffer by a first entity; determining, by the second code entity, whether first data to be returned to the first entity fits into a data area of the first buffer; storing the first data in the data area of the first buffer responsive to determining the first data fits into the data area of the first buffer; and responsive to determining the first data does not fit into the data area of the first buffer, performing first processing by the second entity to store the first data in a dynamically allocated second buffer having a descriptor stored in the first buffer. The descriptor may include the address and size of the second buffer. The first and second entity may be code entities in the same system, or may be different systems that communicate using a remote direct memory access protocol.

Buffer allocation techniques

Information pertinent to a connectivity issue reported by a switch may be determined, compiled and reported; and action may be taken autonomously to address the connectivity issue based on the information. The additional information may be determined by the storage system, including querying a switch in response to the switch notifying the storage system of the I/O error, and the storage system accessing one or more data structures to determine additional information. The storage system may cause I/O communications on the I/O path to be at least temporarily diverted. For example, in response to receiving an I/O request on the I/O path corresponding to the connectivity issue, the storage system may send a communication to the host system that causes the host system not to send additional I/O requests on the I/O path, at least temporarily, as described in more detail elsewhere herein.

Managing I/O connectivity issues

Guaranteeing space availability for thin devices includes reserving space without committing, or fully pre-allocating, the space to specific thin device ranges. Space may be held in reserve for a particular set of thin devices and consumed as needed by those thin devices. The system guards user-critical devices from running out of space, for example due to a 'rogue device' scenario in which one device allocates an excessive amount of space. The system uses a reservation entity, to which a thin device may subscribe, which reserves space for the thin device without allocating that space before it is need to service an I/O request.

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Sharon, MA, United States of America

Igor Fradkin