Emc IP Holding Company LLC

Emc Corporation

Jerome Cartmell

Steven T McClure

Alesia Tringale

Douglas Eric LeCrone

Haim Kopylovitz

Michael J Scharland

Eli Shagam

Qun Fan

Robert DeCrescenzo

Julie Zhivich

Arieh Don

Andrew Chanler

Zhi-Gang Liu

Gabi Benhanokh

Kevin M Tobin

Gabriel Hershkovitz

Sean Pollard

Improved mechanisms and techniques for recording and aggregating trace information from multiple computing modules of a storage system may be provided. On a storage system having multiple computing modules, where each computing module has multiple processing cores, processing cores may record trace information for I/O operations in dedicated local memory&#x2014;i.e., memory in the same computing module as the processing core that is dedicated to the computing module. One of the processing cores may be configured to aggregate trace information from across multiple computing modules into its dedicated local memory by accessing trace information from the dedicated local memories of the other computing modules in addition to its own. The aggregated information in one dedicated local memory then may be analyzed for functionality and/or performance and additional action taken based on the analysis.

Multi-core I/O trace analysis

A node mask of a global metadata structure entry representing an MD portion in GM may be updated when an entry of a local MD table representing the MD portion is removed in response to receiving an IO operation, without negatively impacting performance of the IO operation. An update process that is independent of the process executing the IO operation may update the node mask so that performance of the IO operation is not negatively affected. In response to the entry for the MD portion being removed from the local MD table, an entry may be added to a queue. The update process may include accessing the entries in the queue, and, for each entry, updating the node mask (e.g., clearing a bit representing the processing node) and removing the entry from the queue.

IO metadata management for directly connected host

A high performance logical device having low latency may be provided. I/Os to the logical device may be sent only to a primary director having sole ownership of the logical device. The primary director may perform operations locally for the logical device. Such operations may include allocating global memory for use with the logical device from only a global memory portion that is local to the primary director. The global memory may be a distributed global memory including memory from multiple directors and possibly multiple engines. Cached data for the logical device may be mirrored automatically by the data storage system. Alternatively, the cached data for the logical device may be mirrored using a host-based mirroring technique.

High performance logical device

Storage node blades in a data storage system utilize queue pairs associated with point-to-point links to perform RDMA transactions with memory components associated with other storage node blades. Higher quality of service queue pairs are used for system message transactions and lower quality of service queue pairs are used for remote direct memory access data. Postings to a relatively higher priority queue pair are reduced when a corresponding relatively lower priority queue pair between the same pair of storage nodes via the same switch is starved of bandwidth. Postings to the relatively higher priority queue pair are increased when bandwidth starvation is remediated.

Automatic non-disruptive congestion control of a fabric in a data storage system

A data storage system has first and second computing nodes that are interconnected by a switchless fabric. Each storage node includes first and second paired storage directors with an interconnecting communication link. Atomic operations sent between the computing nodes are mediated by network adapters. Atomic operations sent between paired storage directors via the interconnecting communication link are provided to a network adapter via an internal port and mediated by network adapter. The interconnecting communication links can be used as a backup path for atomic operations in the event of a link failure of the switchless fabric.

Switchless fabric based atomics via partial-proxy

Described are techniques for processing a request to access global memory. For a first processor included on a first of a plurality of boards connected by a fabric, a logical address is determined for a global memory location in a system global memory. A first physical address for the logical address is determined. It is determined whether the first physical address is included in a first global partition of the first board. If so, first processing is performed including updating a memory map to map a window of the first processor's logical address space to a physical memory segment located within the first global partition. Otherwise, if the first physical address is included in a second of the plurality of global partitions physically located on one of the plurality of boards other than said first board, second processing is performed to issue the request over the fabric.

Techniques for global memory management and request processing

Described are techniques for partitioning memory. A plurality of boards is provided. Each of the plurality of boards includes a physical memory portion and a set of one or more processor. The physical memory portion in each of said plurality of boards is partitioned into a plurality of logical partitions including a global memory partition accessible by any processor on any of the plurality of boards and one or more other memory partitions configured for use by one or more processors of said each board. Each of the one or more other memory partitions not being accessible to a processor on a board other than said each board.

Techniques for use with memory partitioning and management

Accessing data memory includes writing data to a first memory location and to a second memory location in response to a request to write data to a memory address that corresponds to both locations, where the first and second memory locations are mirrored, in response to a request to read data from the memory address, reading data from the first memory location or the second memory location based on load balancing, and accessing data from the second memory location in response to a request to access data at the memory address when memory hardware corresponding to the first memory location has failed. Accessing the data memory may include requesting access to a specific one of the first and second memory locations. The memory address may contain a portion that is common to both the first memory location and the second memory location. Hardware coupled to the memory may cause data written using the memory address to be automatically written to the first memory location and the second memory location.

Mirrored memory

Handling a faulting memory of a pair of mirrored memories includes initially causing a non-faulting memory of the pair of mirrored memories to service all read and write operations for the pair of mirrored memories, determining that hardware corresponding to the faulting memory of the pair of mirrored memories has been successfully replaced to provide a new memory, in response to the new memory being provided, causing data to be copied from the non-faulting memory to the new memory while data is being read to and written from the non-faulting memory, and, in response to successful copying to the new memory, causing writes to be performed to both memories of the pair of mirrored memories and selecting one of the pair of mirrored memories for read operations when one or more read operations are performed. Handling a faulting memory may also include, in response to a write being performed to the non-faulting memory while data is being copied from the non-faulting memory to the new memory, causing the write to be performed to the non-faulting memory and the new memory.

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Natick, MA, United States of America

Jerome Cartmell