Abstract: An NMR measurement apparatus includes a transmitting antenna including a transmitter coil, a capacitor, a dissipating component and a restricting component, and a receiving antenna physically separated from the transmitting antenna. A processor is configured to apply a drive signal at a first voltage level to generate a transmission signal having a selected transmission frequency, where the receiving antenna is deactivated during generation, connect the dissipating component to the transmitter coil to dissipate stored energy in the transmitter coil, connect the restricting component to the transmitter coil to restrict the transmitting antenna to a second voltage level smaller than the first voltage level and based on a voltage of NMR signals from the sensitive volume, activate the receiving antenna and detect a NMR signal, where the restricting component is connected to the transmitter coil and restricts the transmitting antenna during the activating and the detecting.

Abstract: An apparatus for performing a downhole nuclear magnetic resonance (NMR) experiment on a subsurface material in a volume of interest includes: a carrier configured to be conveyed through a borehole penetrating the subsurface material; an NMR sensor assembly disposed on the carrier and comprising a static magnetic field source configured to polarize nuclei of the subsurface material in the volume of interest and an antenna configured to receive NMR signals; and a receiver circuit disposed on the NMR sensor assembly and configured to process received NMR signals to perform the downhole NMR experiment; wherein (i) the receiver circuit is disposed in a pressure-excluding enclosure and (ii) the antenna, the static magnetic field source, and the pressure-excluding enclosure are disposed in a pressure-balancing fluid that is at least partially enclosed by an enclosure of non-metallic material.

Abstract: Methods, systems, and computer-readable media for program code allocation based on processor features are disclosed. Analysis of program code is performed using static analysis and/or runtime analysis. The analysis determines one or more processor features invoked by the program code. One or more program execution servers are selected from a plurality of program execution servers based at least in part on the one or more processor features invoked by the program code. One or more selected program execution servers comprise the one or more processor features invoked by the program code, and an additional one or more of the program execution servers lack the one or more processor features invoked by the program code. The program code is executed using the one or more selected program execution servers.

Abstract: One or more configuration parameters for an object gateway instance are received at an interface to a provider network, the parameters including an identifier of a first object store of the provider network for which to cache objects in a first object cache of the object gateway instance and an indication of a data transfer mode that controls when objects written to the first object cache are written to the first object store. The one or more configuration parameters are stored in a data store of the provider network and sent to the object gateway instance. A read request that includes the identifier of the first object store and a first object identifier is received from the object gateway instance, and a first object associated with the first object identifier and stored in the first object store is sent to the object gateway instance.

Abstract: Aspects relate to a framework for utilizing a single API request to manage the creation of consistent snapshots for a set of volumes attached an individual instance in a distributed computing environment. Responsive to receipt of an API request identifying the instance, the multi-volume snapshot service identifies a set of volumes attached to the identified instance. The identified set of volumes can be processed or filtered to eliminate specific volumes or types of volumes, such as boot volumes. In the event that any snapshot creation attempt fails, the multi-volume snapshot service fails the API request and can delete any snapshot data generated prior to the failure.

Abstract: Generally described, one or more aspects of the present application correspond to techniques for automatic recovery from dual isolation in which both the primary and secondary replicas of a volume are stored on isolating servers. The disclosed techniques use handshakes between the client and the replicas to determine which has a better health score. The replica with the better health score becomes the primary replica, and confirms that it and the secondary replica are both in an isolating state. In response, the primary replica seeks a solo blessing, undoes the isolating state at the volume level (the server host will still be in isolating state), and continues handling I/O and peer replication until its healthy peer is complete. These techniques can avoid availability drops when the servers hosting the primary and secondary replicas of a volume enter the isolating state at around the same time.

Abstract: A first request to create a first storage volume to store a first portion of a first logical volume is received by a first block storage server instance. A second request to create a second storage volume to store a second portion of the first logical volume is received by a second block storage server instance. A third request is sent to a third block storage server instance to create a third storage volume to store the second portion of the first logical volume. The second portion of the first logical volume is stored by the third block storage server instance to the third storage volume. A data store containing an identification of each block storage server instance hosting a portion of the first logical volume is updated to remove an identification of the second block storage server instance and add an identification of the third block storage server instance.

Abstract: A first request to launch a first virtual machine to host a block storage server application is received. At least a portion of a storage capacity of one or more storage devices of a host computer system is provisioned to the first virtual machine as a provisioned storage device. The block storage server application is executed with the first virtual machine. As part of executing the block storage server application, a logical volume is created on the provisioned storage device in response to a second request from a block storage service of a provider network to create the logical volume, a third request to perform an input/output operation is received and performed with the logical volume.

Abstract: A first block storage server virtual machine to host a first volume using one or more storage devices of a computer system is executed by the computer system. A second virtual machine having access to a virtual block storage device is executed by the computer system. A block storage client is executed by the computer system. A first block storage operation is received by the block storage client from the second virtual machine, the first block storage operation to perform on the virtual block storage device. A message is sent by the block storage client to the first block storage server virtual machine to cause the first block storage server virtual machine to perform the block storage operation with the first volume.

Abstract: Generally described, one or more aspects of the present application correspond to techniques for creating multiple encrypted block store volumes of data from an unencrypted source. These encryption techniques can use a transform fleet as an intermediary use between the unencrypted source and the encrypted volumes. The transform fleet can obtain data of the volume from one or both of two sources—an object storage “snapshot” a block storage “source volume”—and can then apply the appropriate encryption key for performing the encryption of a particular volume.

Abstract: Notice of migration of a portion of a data volume from a first location to a second location is received by a first computer system from a second computer system, where the data volume is separated over a network from the first computer system. A third computer system, separated over a network from the first computer system, is caused to invalidate a mapping between the portion and the first location. An indication that the third computer system seeks access to the portion is identified. A third computer system is enabled, by providing a mapping between the portion and the second location, to access portion at the second location.

Abstract: Server computers often include one or more input/output (I/O) devices for communicating with a network or directly attached storage device. The data transfer latency for request can be reduced by utilizing ingress data placement logic to bypass the processor of the I/O device. For example, host memory descriptors can be stored in a memory of the I/O device to facilitate placement of the requested data.

Abstract: A method for transforming an earth formation and/or a completion component for the earth formation based on estimating a parameter of the earth formation includes: performing a nuclear magnetic resonance (NMR) experiment on the earth formation, the NMR experiment includes transmitting an initial radio-frequency (RF) pulse and a series of refocusing RF pulses; detecting a truncated free induction decay (FID) signal following the initial RF pulse and a spin echo following at least one refocusing RF pulse, the truncated FID signal missing an initial part of a total FID signal; reconstructing the total FID signal using the truncated FID signal, the detected spin echo, and a calculated or measured time between end of transmitting the initial RF pulse and beginning of receiving the truncated FID signal; estimating the parameter using the total FID signal; and transforming the earth formation and/or the completion component based on the estimated property using transformation-equipment.

Abstract: A first request to create a first storage volume to store a first portion of a first logical volume is received by a first block storage server instance. A second request to create a second storage volume to store a second portion of the first logical volume is received by a second block storage server instance. A third request is sent to a third block storage server instance to create a third storage volume to store the second portion of the first logical volume. The second portion of the first logical volume is stored by the third block storage server instance to the third storage volume. A data store containing an identification of each block storage server instance hosting a portion of the first logical volume is updated to remove an identification of the second block storage server instance and add an identification of the third block storage server instance.

Abstract: A first block storage server virtual machine to host a first volume using one or more storage devices of a computer system is executed by the computer system. A second virtual machine having access to a virtual block storage device is executed by the computer system. A block storage client is executed by the computer system. A first block storage operation is received by the block storage client from the second virtual machine, the first block storage operation to perform on the virtual block storage device. A message is sent by the block storage client to the first block storage server virtual machine to cause the first block storage server virtual machine to perform the block storage operation with the first volume.

Abstract: A first request to launch a first virtual machine to host a block storage server application is received. At least a portion of a storage capacity of one or more storage devices of a host computer system is provisioned to the first virtual machine as a provisioned storage device. The block storage server application is executed with the first virtual machine. As part of executing the block storage server application, a logical volume is created on the provisioned storage device in response to a second request from a block storage service of a provider network to create the logical volume, a third request to perform an input/output operation is received and performed with the logical volume.

Abstract: Generally described, one or more aspects of the present application correspond to techniques for modifying volume encryption status, either by creating an encrypted copy of an unencrypted source volume or by re-encrypting the replica with a different key than the source volume. This can be accomplished using an intermediary transform fleet that stores the encryption key(s) and performs encryption (and decryption, in cases where the source is encrypted). Further, these techniques can implement a state refresh for any client attached to the volume in order to equip the client to handle the different encryption state of the encrypted volume.

Abstract: First information about regions of storage space in a storage environment available for a volume is provided to a service provider, with the storage environment being external to the service provider. The service provider is notified that information usable to locate a storage destination of a portion of the volume is unavailable. Second information that includes the storage destination in the storage environment is obtained from the service provider. A data operation is performed at the storage destination, with the storage destination determined based at least in part from the second information.

Abstract: A nuclear magnetic resonance apparatus includes a magnet assembly, a transmitting antenna configured to generate an oscillating magnetic field in a sensitive volume within an earth formation, and one or more receiving antennas configured to detect a nuclear magnetic resonance signal originating in the sensitive volume. The one or more receiving antennas are arranged relative so that the one or more receiving antennas are inductively decoupled from the transmitting antenna, a first portion of the surface area of the one or more receiving antennas overlapping a first region of the transmitting antenna in which a magnetic flux of the transmitting antenna is in a first direction, and a second portion of the surface area of the one or more receiver antennas overlapping a second region of the transmitting antenna in which the magnetic flux is in a second direction predominantly opposed to the first direction.

Abstract: A distributed system may implement opportunistic resource migration to optimize resource placement. Resources may be placed amongst different resource hosts of a distributed system. An evaluation of the current placement may be performed according placement criteria that improve placement of the resources at the distributed system. Based on the evaluation, the prospective migration of resources that exceed an improvement threshold may be identified as candidate resources to migrate. Migration for the candidate resources may be opportunistically performed. In some embodiments, a priority may be assigned to the candidate resources according to which the candidate resources are selected for performing migration.