Netapp, Inc.

Other

William D Dallas

Sangramsinh Pandurang Pawar

Per Olov Wahlstrom

Rajesh Rajaraman

Houze Xu

Chris A Busick

Joseph Brown

Bhoovaraghan Subramanian

Fnu Sahasranshu

Rajesh Rajarman

John David McA'Nulty

Sowkoor Sunad Bhandary

Sridhar Balachandriah

Gunalan Perumal Vijayan

Edward Barron

Bhaskar Singhal

Vijay Chandra Hanchatey

Ruitao Duan

Systems and methods for flushing an operation log journal to both ephemeral storage and persistent storage during a shutdown sequence of a virtual storage system to minimize data-loss scenarios are provided. According to one embodiment, the shutdown or reboot scenarios that result in loss of data are minimized by using persistent storage as a backup to ephemeral storage when the scenario results in rehosting of virtual storage system. For example, responsive to an event indicative of an imminent shutdown or reboot of the virtual storage system, vNVRAM memory may be flushed to both ephemeral storage and persistent storage (e.g., a boot disk). In this manner, when the virtual storage system is rehosted after an unplanned shutdown or reboot resulting from an unrecoverable host error (other than an unrecoverable hardware failure), the operation log journal may be recovered from persistent storage to facilitate vNVRAM replay and avoid data loss.

Reducing potential data-loss scenarios when using ephemeral storage as backing storage for journaling by a virtual storage system

Systems and methods for making use of non-persistent storage as the journaling storage media for a virtual storage system are provided. According to one embodiment, in order to meet the needs of Extreme Low Latency Workloads while also seeking to provide predictable performance and the lowest possible latency, ephemeral storage of the virtual storage system is used to preserve state information (e.g., in the form of boot arguments and an operation log journal) across a host failure recovery scenario in which the virtual storage system is expected to be redeployed within a compute instance brought up by a cloud environment of a hyperscaler on the same host, thereby providing improved data durability (fewer host failure scenarios that result in lost data) as compared to the use of ephemeral memory of the compute instance and lower write latency than the use of persistent storage provided by the cloud environment.

Using ephemeral storage as backing storage for journaling by a virtual storage system

Systems and methods for performing a fast resynchronization of a mirrored aggregate of a distributed storage system using disk-level cloning are provided. According to one embodiment, responsive to a failure of a disk of a plex of the mirrored aggregate utilized by a high-availability (HA) pair of nodes of a distributed storage system, disk-level clones of the disks of a healthy plex may be created external to the distributed storage system and attached to the degraded HA partner node. After detection of the cloned disks by the degraded HA partner node, mirror protection may be efficiently re-established by assimilating the cloned disks within the failed plex and then resynchronizing the mirrored aggregate by performing a level-1 resync of the failed plex with the healthy plex based on a base file system snapshot of the healthy plex. In this manner, a more time-consuming level-0 resync may be avoided.

Fast resynchronization of a mirrored aggregate using disk-level cloning

Systems and methods for performing a fast resynchronization of a mirrored aggregate of a distributed storage system using disk-level cloning are provided. According to one embodiment, responsive to a failure of a disk of a plex of the mirrored aggregate utilized by a high-availability (HA) pair of nodes of a distributed storage system, disk-level clones of the disks of the healthy plex may be created external to the distributed storage system and attached to the degraded HA partner node. After detection of the cloned disks by the degraded HA partner node, mirror protection may be efficiently re-established by assimilating the cloned disks within the failed plex and then resynchronizing the mirrored aggregate by performing a level-1 resync of the failed plex with the healthy plex based on a base file system snapshot of the healthy plex. In this manner, a more time-consuming level-0 resync may be avoided.

Systems and methods for facilitating performance of data tiering by detecting and persisting types of backing storage of cloud volumes that are available for use by a virtual storage system are provided. In one example, during a boot phase of the virtual storage system within a compute instance of a cloud environment, information regarding a type of backing storage for each of multiple storage devices associated with the compute instance that is not available via hypervisor APIs is obtained via an API exposed by the cloud environment. The multiple storage devices may then be initialized to facilitate subsequent use of a subset thereof in connection with performing data tiering by persisting information indicative of the type of backing storage for the storage device within a reserved header region on each storage device.

Detecting and persisting across boots types of backing storage of cloud volumes available to a virtual storage system

A request that indicates a component that can be quiesced is received at a first node. It is determined that quiescence of the component might impact an endpoint. A request for identification of at least one path between a second node and the endpoint is sent to the second node. It is determined, based on a response received from the second node, whether the endpoint will be accessible to the second node if the component is quiesced. In response to a determination that the endpoint will be accessible to the second node if the component is quiesced, a positive analysis outcome is indicated. In response to a determination that the endpoint will not be accessible to the second node if the component is quiesced, a negative analysis outcome is indicated.

Clustered storage system path quiescence analysis

An indication of an event is received at a storage controller. The indication of the event corresponds to a first severity. It is determined that the event is associated with a first stream of commands. It is determined whether the indication of the event is the first indication of the event received by the storage controller. If the indication of the event is the first indication of the event received by the storage controller, a maximum allowed count of in-flight commands to be less than a current count of in-flight commands is set. If the indication of the event is not the first indication of the event received by the storage controller, it is determined that the first severity is greater than a second severity corresponding to a previously received indication. If the first severity is greater than the second severity, the maximum allowed count of in-flight commands is decreased.

In-flight command queue depth management

An indication of an event occurrence is received. The indication of the event occurrence is associated with a severity. A tag associated with the indication of the event occurrence is determined. It is determined whether the tag is the same as a preceding tag. In response to a determination that the tag is not the same as the preceding tag, a component is notified of the event occurrence, the tag is stored for later use, and an indication of the severity associated with the indication of the event occurrence is stored.

Event based tagging of storage system commands

Method and system for handling error events on a current path for processing an I/O request for reading information from and writing information to a storage space is provided. A system is able to communicate with the storage space via more than one path. If the current path reports an error event, then an alternate path quality is determined to ascertain whether the alternate path will generate an error similar to the current path. The alternate path quality is determined based on a plurality of factors which are assigned certain weights. The weights are determined based on a likely contribution of each factor to a repetition of the error reported by the current path. If the alternate path quality is equal to or exceeds a programmable threshold value, then the alternate path is selected.

Method and system for path selection in a network

An earphone wire cover with three separate arms resembling drinking straws joined together in a Y-configuration into which the ear phone speakers and plug are inserted and passed through. These covers enclose most of the wire from the electronic device to the earphones. The three sections are joined together with a flexible tape or string so that, when the earphones are to be stored, the three arms can be brought together as three parallel tubes holding the bulk of the wire by simply flipping the bottom section into alignment with the upper two sections. The invention can be easily re-deployed by simply folding the bottom section out again and separating the top ends to make a Y. An alternate embodiment of the invention can have a microphone hole in one of the arms.

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Merrimack, NH, United States of America

William D Dallas