Dell Products Inc.

Vasudevan Subramanian

Nagapraveen Veeravenkata Seela

Vamsi K Vankamamidi

Girish Sheelvant

Philippe Armangau

Vinay G Rao

Sanjib Mallick

Alan Lee Taylor

Dmitry Nikolayevich Tylik

Socheavy D Heng

Michael C Brundage

G Paul Koning

Lazarus J Vekiarides

Peter C Hayden

Paula Long

Maher Kachmar

Hsin H Lee

Satyanarayana R Goluguri

Owen Martin

Walter Forrester

Frederic Corniquet

Dazhi Dong

Gajanan S Natu

Kosta Economou

Joseph A Perry

In at least one embodiment, processing can include: configuring a file server on a first node of a storage system, the file server including a file system configured on a volume; configuring a first path exposing the volume to the file server as active-optimized (AO) and configuring a second path exposing the volume to the file server as active-non-optimized (ANO); for the volume, while the first path's state is AO and the second path's state is ANO, determining an internode I/O workload imbalance between the first node and the second node; and responsive to determining the internode I/O workload imbalance, reducing or removing the internode I/O workload imbalance including: redirecting I/O workload of the volume from the first node to the second node over the second path by modifying the first path's state from AO to ANO and by modifying the second path's state from ANO to AO.

Techniques for node resource balancing

Cluster management logic in a storage appliance of a storage cluster receives messages that are automatically transmitted periodically by unconfigured storage appliances. The unconfigured storage appliances do not belong to the storage cluster, and the messages contain properties of the unconfigured storage appliances. The messages may be multicast DNS (Domain Name Service) messages. The cluster management logic determines a level of compatibility of each one of the unconfigured storage appliances with regard to the storage cluster, based on the received properties. Determining the level of compatibility of each unconfigured storage appliance with the storage cluster may include assigning one of multiple compatibility level categories to each unconfigured storage appliance. The compatibility level categories may be or include a) incompatible, ii) compatible with warning, and/or c) compatible, and may be displayed in a graphical user interface that is used to add unconfigured storage appliances to the storage cluster.

Unconfigured storage appliance compatibility checking for a storage cluster

A method, computer program product, and computer system for receiving, by a computing device, a write request, wherein the write request may be received by a file system of the computing device. Data associated with the write request may be stored in a cache of the file system and a cache of a block storage system corresponding to the file system. A tag associated with the data in the cache of the block storage system may be received by the block storage system. The data in the cache of the block storage system may be freed after flushing the data to persistent storage based upon, at least in part, the tag associated with the data in the cache of the block storage system. As a result, there is optimization for the read path due to no double caching in the block cache.

Systems and methods for cooperative caching between file systems and block storage

Techniques providing data path strategies for improving storage performance at DR sites. The techniques include receiving, in an asynchronous replication process, a large replication data transfer including data changes of a production volume since the last synchronization to a replica volume, partitioning the replication data into multiple small write requests, tagging each small write request as a write request to the replica volume, and performing early evicting, from cache memory, all cache pages used to cache host data specified in the small write requests; deep compression of contiguous host data specified in the small write requests; stream separation on the small write requests, each small write request being tagged as corresponding to a specific production site; and/or flushing host data having the same retention period to a specific region of physical storage space for the replica volume, each small write request being tagged with hint information indicating the retention period.

Data path strategies for replica volumes

An apparatus in one embodiment includes at least one processing device comprising a processor coupled to a memory. The at least one processing device is configured to identify a logical storage device accessible in at least first and second storage systems, to measure response times for accessing the logical storage device in each of the first and second storage systems, and to modify, based at least in part on the measured response times, asymmetric access state settings for the logical storage device. Modifying asymmetric access state settings for the logical storage device in some embodiments illustratively comprises modifying asymmetric logical unit access (ALUA) or asymmetric namespace access (ANA) state settings for the logical storage device. Such modifications are illustratively performed in a dynamic manner that responds to variations in the measured response times so as to facilitate load balancing across storage controllers of the first and second storage systems.

Dynamic configuration of logical storage devices accessible across multiple storage systems

A power controller for a data storage system automatically selects different power modes based on changing forecasts of availability of renewable energy. The power modes indicate settings for each of a plurality of hardware resources, such as processors, fans, memory, and drives. At times when the storage system can operate at less than the maximum level of performance in terms of IO latency or IOPS, power consumption of one or more of the hardware resources is reduced to a degree corresponding to availability of renewable energy. For example, the hardware resources may be operated in a relatively higher power mode when renewable energy is available than when renewable energy is unavailable. The storage system may be configured to automatically implement a low power mode when power from all sources is in limited supply, e.g., during a brownout.

Autonomous power management for sustainable storage

A method, computer program product, and computing system for determining a recovery point object (RPO) value for a storage object. An amount of data to transfer from the storage object to a disaster recovery site is determined. A data replication transfer schedule for the storage object is generated based upon, at least in part, the RPO value and the amount of data to transfer. Data is asynchronously transferred from the storage object to the disaster recovery site using the data replication transfer schedule.

System and method for asynchronously transferring replication data

Techniques are disclosed for storage resource resynchronization using pending IO requests. For example, a method includes, upon detecting a failed network: quiescing IO activity in progress; identifying storage resources and associated pending IO requests; for each storage resource: creating a first snapshot of the storage resource; for each pending IO request, marking blocks specified by the pending IO request as modified; unquiescing the quiesced IO activity; upon detecting the network has been restored: creating a second snapshot of each storage resource; remote mirroring, to the destination, a copy of differences of each source storage resource to the destination storage resource, wherein the differences are identified by comparing the first and the second snapshot; transmitting a request for the destination to create a third snapshot comprising a snapshot of each destination storage resource; and triggering the destination to process the third snapshot to identify storage resources based on the differences.

Storage resource resynchronization using pending IO requests

Techniques can include: establishing a synchronous replication configuration for a group of stretched resources configured for bi-directional synchronous replication between a first site and a second site; and performing processing to implement a change or modification operation of the group of one or more existing stretched resources. The processing can include performing a three phase workflow comprising: a preparation phase that prepares the group for the change or modification operation of the group; a commitment phase that commits the change or modification operation to the group; and a synchronization phase that synchronizes content of the group in accordance with the change or modification operation to the group. Each stretched resource of the group can be configured from local resources of the first and second sites where such local resources have the same identity when exposed to an external host over paths from the first and second sites.

Techniques for implementing modifications to a stretched resource group

Techniques for dynamically configuring a multi-site storage system such as a metro cluster using input/output (IO) response time (RT) hints from a host computer. The techniques include receiving IO RT hints at each storage appliance of the multi-site storage system from the host computer, which is initially identified as 'local' or “remote” relative to a physical location of the storage appliance. The techniques further include modifying, by the storage appliance, an initial local or remote identification of the host computer relative to the physical location of the storage appliance based on the received IO RT hints, dynamically changing, by the storage appliance, states of IO paths between the host computer and nodes of the storage appliance based on the modified local or remote identification of the host computer, and providing, by the storage appliance, notification of the changed states of the IO paths to the host computer.

Dynamic metro configuration using storage area network (SAN) response time hints from host computer

Techniques can include: configuring source sites in a replication configuration with a target site; receiving, at a first of the source sites from a host, a write I/O to a target location of a source storage object of the source site; sending a replicated write corresponding to the write I/O from the first source site to the target site, wherein the replicated write writes to the target location of a target storage object of the target site; prioritizing the replicated write, based at least in part, on a site-level priority associated with the first source site; placing the first replicated write in a first queue of a first plurality of queues based, at least in part, on the site level priority associated with the first source site; selecting the first replicated write from said first queue; and servicing the first replicated write.

Techniques for prioritizing replicated writes from multiple sources on a disaster recovery site

Techniques for resynchronizing storage resources of two sites configured for synchronous replication can include tracking in-progress write requests in a map. Responsive to a site failure or a replication link failure resulting in failure or fracture of the synchronous replication, processing can be performed to resynchronize impacted resources of the two sites configured for synchronous replication. The processing can use the in-progress write requests in combination with resource snapshots and snapshot differences to resynchronize the impacted resource of the two sites. In at least one embodiment, the synchronous replication configuration can include active paths between both sites and a host. In at least one embodiment, the synchronous replication configuration can include an active path between the host and one site, and a passive path between the host and the second site. The synchronous replication can be bi-directional or two-way synchronous replication between the two sites.

Techniques for optimized data resynchronization between replication sites

Techniques can include: establishing synchronous replication configurations between first and second sites for a group of stretched resources and a stretched resource; and performing processing that adds the stretched resource to the group. While both the group and stretched resource are in an active-active state and replicating data, existing replication session objects associated with stretched resource on both sites can be deleted while retaining remaining portions of layered services stacks corresponding to the stretched resource on both sites. A first remaining portion can be added to a first replication session object corresponding to the group on the first site. A second remaining portion can be added to a second replication session object corresponding to the group on the second site. Even though the existing replication session objects associated with the stretched resource may be deleted, the existing configuration corresponding to the stretched object can be retained.

Techniques for adding and removing storage objects from groups

A data storage system continually monitors a loading level of processing requests from host computers relative to a predetermined threshold. In response to the loading level not exceeding the predetermined threshold, a first bulk operation request is responded to with a normal acknowledgment issued without a rate-managing delay. In response to the loading level exceeding the predetermined threshold, a third bulk operation request is responded to with a delayed acknowledgment issued with the rate-managing delay and thus delaying issuance by a requesting host of a subsequent fourth bulk operation request to a delayed time after the third bulk operation request. The use of the delayed acknowledgement throttles the rate of bulk operations and thus limits adverse performance impact to other, latency-sensitive operations such as regular read and write operations.

Data storage system employing delayed responses to influence rate of bulk storage operations

A data storage system continually monitors a loading level of processing requests from host computers relative to a predetermined threshold. In response to the loading level not exceeding a predetermined threshold, a first identification request is responded to with a full response identifying all data blocks over a first complete range of a first bulk storage operation. In response to the loading level exceeding the predetermined threshold, a second identification request is responded to with a partial response identifying a subset of data blocks over only a portion of a second complete range of a second bulk storage operation. The partial response causes a host to first process the subset of data blocks and then send an additional identification request for additional blocks of the second complete range, effectively reducing the rate of bulk storage operations and their effect on other, latency-sensitive operations such as reads and writes.

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Nashua, NH, United States of America

Vasudevan Subramanian