Abstract: In one aspect, a method includes storing data in a distributed storage environment that includes data servers and configuring each data server to mark a respective bit map for each block of data changed. In another aspect, an apparatus includes electronic hardware circuitry configured to store data in a distributed storage environment that includes data servers and to configure each data server to mark a respective bit map for each block of data changed. In a further aspect, an article includes a non-transitory computer-readable medium that stores computer-executable instructions. The instructions cause a machine to store data in a distributed storage environment that includes data servers and configure each data server to mark a respective bit map for each block of data changed. In each of the aspects above each data server is configured to handle a respective portion of a logical unit.

Abstract: Described are techniques for automatically configuring target port settings. A set of target port settings of a target port of a data storage system is initialized in accordance with a first target port setting configuration. It is determined whether the data storage system supports host registration. If the data storage system supports host registration, first processing is performed that includes registering a first host with the data storage system, wherein registering includes sending first information from the first host to the data storage system, the first information being sent from an initiator port of the first host to the target port; determining, using the first information, whether the set of target port settings of the target port require modification for use by the first host; and modifying the set of target port settings in accordance with the first information if the set of target port settings require modification.

Abstract: In one aspect, a method includes configuring a kernel driver to record data block changes of a logical unit in a bit map and using the bitmap to perform an incremental backup of the logical unit. In another aspect, an apparatus includes electronic hardware circuitry configured to configure a kernel driver to record data block changes of a logical unit in a bit map and use the bitmap to perform an incremental backup of the logical unit. In a further aspect, an article includes a non-transitory computer-readable medium that stores computer-executable instructions. The instructions cause a machine to configure a kernel driver to record data block changes of a logical unit in a bit map and use the bitmap to perform an incremental backup of the logical unit.

Abstract: A computer of a data processing system includes a software encryption engine and path circuitry that initially provides one or more paths for conveying data of storage I/O requests to and from a storage device, the paths including an encrypting path having a hardware encrypting component. According to a failover technique, in a first operating state, (a) the data of the storage I/O requests is conveyed via the encrypting path with encryption and decryption of the data being performed by the hardware encrypting component, and (b) monitoring is performed for occurrence of an event indicating that the hardware encrypting component has become unavailable for encrypting and decrypting the data of the storage I/O requests.

Abstract: An improved technique for storing I/O metrics includes assigning metric values to data buckets held in kernel memory. Each data bucket covers a particular range of values of a respective metric and is configured as a counter, whose count is incremented each time the multipathing driver obtains or computes a metric value that falls within the range of the data bucket. Bucket counts can be read by an external program to obtain aggregate information about I/O metrics over time. The aggregate information can be fed back to the multipathing driver to enable improved selections of paths for conveying data to and from a storage array.

Abstract: A technique manages operation of a host computer having access to a storage volume on a storage system via two or more distinct paths. The technique involves operating a multipathing driver within the host computer, the multipathing driver controlling path access from the host computer to the storage volume. The technique further involves operating a host bus adaptor (HBA) driver within the host computer to interface the host computer to a fabric connecting the host computer to the storage system. The technique further involves conveying fabric topology state change event information from the HBA driver to the multipathing driver to enable the multipathing driver to take action in response to fabric topology state change events. In some arrangements, an event monitoring handler receives fabric event information from registered state change notifications (RSCNs) containing fabric event information from the HBA driver, and forwards that information on to the multipathing driver.

Abstract: Described are techniques for achieving service level objectives. A first service level objective for a first tenant of a data storage system may be received. The first tenant may have data stored in a first set of devices of the data storage system. The first service level objective may include a first value for a first metric. The first tenant may be located on a first host and may issue I/O operations directed to the first set of devices. A first calculated value for the first metric may be determined using one or more measured values obtained at the first host. It may be determined, using the first calculated value for the first metric, whether the first service level objective for the first tenant is violated. Responsive to determining the first service level objective for the first tenant is violated, first processing may be performed to selects a remediation action.

Abstract: Data migration is performed in a cluster of host computers each using a mechanism associating data with a source LUN. During a synchronization operation the contents of the source LUN are copied to the target LUN while ongoing normal source LUN writes are cloned to the target LUN. A datapath component of an agent coordinates the writes at the target LUN to maintain data consistency. Upon completion of synchronization, each host stops the write cloning and disables access to the source LUN, in conjunction with a modification of the mechanism to newly associate the data with the target LUN. Depending on the type of mechanism and system, the modification may be done either disruptively or non-disruptively, i.e., with or without stopping normal operation of software of the host computers.

Abstract: Data is non-disruptively migrated from a source LUN to a target LUN in an active-active cluster with coordination of a host-based copy sweep with duplicating of ongoing writes of all hosts, using iteration and changed block tracking (CBT). During a first iteration, one host performs the copy sweep, and the locations of new application writes at other hosts are recorded in respective CBT records. In each subsequent iteration, the data blocks of the CBT-recorded writes are copied to the target LUN while the locations of new writes are recorded in new CBT records. A final iteration is done with I/O suspended to completely synchronize the target LUN with the source LUN, and the migration then proceeds to a committed state in which the target LUN is used in place of the source LUN. The one host may use write cloning or CBT recording like the other hosts.

Abstract: A technique electronically controls commitment of a change to stored information. The technique involves accessing a reviewer database to ascertain a set of reviewers assigned to review proposed changes to the stored information. The technique further involves electronically notifying the set of reviewers to review a particular proposed change to the stored information after the set of reviewers is ascertained. Each reviewer is able to electronically approve or reject the particular proposed change to the stored information. The technique further involves (i) electronically preventing commitment of the particular proposed change to the stored information while less than a predefined number of electronic approvals has been received from the set of reviewers and (ii) electronically enabling commitment of the particular proposed change to the stored information upon receipt of the predefined number of electronic approvals from the set of reviewers.

Abstract: Described are techniques for upgrading a driver. A driver is installed which includes an upgrade facility, a base driver and a first set of one or more driver extension modules for processing input/output operations for one or more devices. Processing is performed to upgrade the driver using the upgrade facility. The processing includes loading one or more upgrade modules associated with a second version of said driver and performing cutover processing for each of the one or more devices.

Abstract: A host computer automatically detects an encapsulating volume in a not ready device state and executes setup and synchronize operations, where the encapsulating volume is a virtualization of a physical volume. Setup applies access control to the encapsulating volume, and synchronize transitions the encapsulating volume to a protected device state. In response to a signal conveying an administrator's instruction to proceed, a commitment operation is automatically executed by atomically (a) removing the access control on the encapsulating volume to allow application access, (b) applying access control to the physical volume, and (c) remapping a device name to reference the encapsulating volume, the commitment operation also causing a transition of the encapsulating volume to a normal device state in which the encapsulating volume is available for normal application access. The technique can also include de-encapsulation and a data migration process employing the encapsulation and de-encapsulation.

Abstract: Described are techniques for parameter selection. First processing is performed that migrates data of a first device from an origin to a destination data storage system. The first processing includes cutover processing. After cutover processing is performed, requests to the first device are serviced by the destination data storage system rather than the origin data storage system. During first processing, occurrence of cutover processing is detected. Responsive to detecting the occurrence of cutover processing, second processing is performed to update one or more parameters each having a value that varies in accordance with a type of physical data storage system. Prior to second processing, the parameters have values determined in accordance with a type of physical data storage system of the origin data storage system, and after second processing, the parameters have values determined in accordance with a type of physical data storage system of the destination data storage system.

Abstract: An improved technique for managing access to performance data of a kernel driver includes acquiring performance data in the kernel driver over identified intervals of time marked by the kernel driver itself and transferring the performance data to a persistence manager outside the kernel, where client applications can access the performance data and/or post-processed versions thereof without disturbing the operation of the kernel driver.

Abstract: A host computer accesses a storage volume via multiple paths and maintains path mode information identifying either an active or standby operating mode. An active-mode path is generally usable, and a standby-mode path is usable under exceptional conditions such as non-availability of an active-mode path. A reason identifier identifies a first operating condition causing the path to be placed in the standby mode. Upon a path-activating event for a standby-mode path, if there is a second operating condition indicating that the path should be maintained in the standby operating mode, then the path is maintained in the standby operating mode and the path mode information is set to identify the second operating condition, and otherwise the operating mode is set to active. A path-activating event can be a manual action by a user or automatic action such as expiration of an aging timer to re-attempt use of a standby path.

Abstract: A computer implemented method for creating an encrypted logical unit is provided. A first identification number is received, the first identification number associated with a first encryption key used to encrypt a first logical unit. The first identification number and the first encryption key are stored at a first secure location, where the first secure location provides the first encryption key to a requester in response to receiving the first identification number from the requester, assuming the requester provides security credentials. A first metadata storage space is defined on the first logical unit, the first metadata storage space comprising a region on the first logical unit that remains unencrypted. The first identification number is stored in the first metadata storage space on the first logical unit.

Abstract: Systems and methods are provided for selecting a path through which to send data in a host-based multi-path system. In one embodiment, a system includes a management server that determines a topology of the network and analyzes a plurality of paths for sending data through the network. The management server may also create a path quality index based on the topology and the analysis, the path quality index indicating a quality of individual paths within the plurality of paths. The system further includes a host that receives the path quality index from the management server and automatically selects, based on the path quality index, a path from the plurality of paths through which to send data.

Abstract: Described are techniques for automatically configuring target port settings. A set of target port settings of a target port of a data storage system is initialized in accordance with a first target port setting configuration. It is determined whether the data storage system supports host registration. If the data storage system supports host registration, first processing is performed that includes registering a first host with the data storage system, wherein registering includes sending first information from the first host to the data storage system, the first information being sent from an initiator port of the first host to the target port; determining, using the first information, whether the set of target port settings of the target port require modification for use by the first host; and modifying the set of target port settings in accordance with the first information if the set of target port settings require modification.

Abstract: In one aspect, a method of compressing data includes splitting an I/O into smaller I/Os based on an I/O throughput. The size of the smaller I/Os are equal or less than a set block size. The method also includes asynchronously compressing the smaller I/Os. In another aspect, an article includes a non-transitory machine-readable medium that stores executable instructions. The instructions cause a machine to split an I/O into smaller I/Os based on an I/O throughput and asynchronously compress the smaller I/Os. The size of the smaller I/Os being equal or less than a set block size. In a further aspect, a system includes circuitry configured to split an I/O into smaller I/Os based on an I/O throughput and asynchronously compress the smaller I/Os. The size of the smaller I/Os being equal or less than a set block size.

Abstract: Systems and methods are provided for selecting a path for an I/O in a storage area network. In one embodiment, a method comprises receiving path configuration information for paths associated with a host device connected to the storage area network, a listing of components within the storage area network, and a notification of a component failure within the storage area network. The method may also comprise correlating the received path configuration information, the received listing of components, and the received notification of component failure to determine one determine one or more paths associated with the host device affected by the component failure. The method may further comprise transmitting to the host device an alert for the one or more affected paths.