Abstract: Service level objectives (SLOs) defined for a storage system are associated with VMs running on hosts. For an I/O operation for a virtual machine (VM) running on a host system, storage processing is performed on the I/O operation in accordance with the SLO defined for the VM. The same storage system-defined SLOs may be applied to VMs running on multiple host systems. SLOs may be maintained by the storage array and shared with one or more host systems in I/O communication with the storage system. SLOs may be defined using a user interface of a storage system, host system, virtualizer control station or other component of a storage network, and communicated to the storage system, which may maintain the SLOs, and may disseminate them to one or more hosts. The SLOs then may be associated with VMs running on the hosts and tagged to I/O communications corresponding to the VMs.

Abstract: Moving data among a plurality of non-volatile storage devices of a storage device includes accumulating credits at each of a plurality of periodic intervals for separate portions of the devices, wherein the credits correspond to a wear rating for each of the devices, reducing credits for each of the portions at each of the periodic intervals based on an amount of data written to each of the portions during each of the intervals, on the wear rating for each of the devices, and on a percent life used for the devices, and moving data from a first one of the portions having a relatively low amount of credits to a second one of the portions having a relatively high amount of credits. The devices may be solid state drives. The wear rating may be a drive writes per day rating provided by a manufacture of the solid state drive.

Abstract: Service level objectives (SLOs) defined for a storage system are associated with virtual machines running on hosts. For an I/O operation for a virtual machine (VM) running on a host system, storage processing is performed on the I/O operation in accordance with the SLO defined for the VM. The same storage system-defined SLOs may be applied to VMs running on multiple host systems. SLOs may be maintained by the storage array and shared with one or more host systems in I/O communication with the storage system. SLOs may be defined using a user interface of a storage system, host system, virtualizer control station or other component of a storage network, and communicated to the storage system, which may maintain the SLOs, and may disseminate them to one or more hosts. The SLOs then may be associated with VMs running on the hosts and tagged to I/O communications corresponding to the VMs.

Abstract: A method of cache hit ratio simulation using a partial data set includes determining a set of sampled addresses, the set of sampled addresses being a subset of all addresses of a storage system of a storage environment. The method further includes using, by a simulation engine, a cache management algorithm to determine a cache hit ratio of the sampled addresses, the cache management algorithm being also used by a cache manager to place a portion of the addresses of the storage system into cache during a runtime operation. The method further includes determining a quantity of memory access operations to frequently accessed addresses in the set of sampled addresses, and correcting, by the simulation engine, the cache hit ratio of the sampled addresses based on the quantity of memory access operations to the frequently accessed addresses in the set of sampled addresses. The simulation also handles sequential operations accurately.

Abstract: A method of cache hit ratio simulation using a partial data set includes determining a set of sampled addresses, the set of sampled addresses being a subset of all addresses of a storage system of a storage environment. The method further includes using, by a simulation engine, a cache management algorithm to determine a cache hit ratio of the sampled addresses, the cache management algorithm being also used by a cache manager to place a portion of the addresses of the storage system into cache during a runtime operation. The method further includes determining a quantity of memory access operations to frequently accessed addresses in the set of sampled addresses, and correcting, by the simulation engine, the cache hit ratio of the sampled addresses based on the quantity of memory access operations to the frequently accessed addresses in the set of sampled addresses. The simulation also handles sequential operations accurately.

Abstract: A host server in a server cluster has a memory allocator that creates a dedicated host application data cache in storage class memory. A background routine destages host application data from the dedicated cache in accordance with a destaging plan. For example, a newly written extent may be destaged based on aging. All extents may be flushed from the dedicated cache following host server reboot. All extents associated with a particular production volume may be flushed from the dedicated cache in response to a sync message from a storage array.

Abstract: Techniques for processing I/O operations may include: randomly assigning extent identifiers of extents to RAID groups; receiving write activity information for the extents for a sampling period; for each of the RAID groups, performing stream detection processing in accordance with the first write activity information and determining stream groups, wherein each stream group of one of the RAID groups includes extents of the RAID group belonging to a same write stream in the RAID group, wherein stream groups across all RAID groups are uniquely identified using stream group identifiers; tagging a write operation directed to one of the extents with a first stream group identifier denoting a stream group including the one extent; and issuing the write operation to a solid state drive of one of the RAID groups. Stream detection may use K-Means clustering algorithm. An aggregate address range of logical devices is mapped to the extent identifiers.

Abstract: Techniques and mechanisms for establishing and implementing performance objectives for an application based at least in part on a workload type of the application. A system includes a storage system on which an application imposes a workload by utilizing storage resources of the storage system, and a performance level has been associated with the application. A workload type is associated with the application based on the type of workload, and a performance objective is determined for the application based on the performance level and the workload type of the application. The storage resources are manipulated to achieve the performance objective.

Abstract: A host server in a server cluster has a memory allocator that creates a dedicated host application data cache in storage class memory. A background routine destages host application data from the dedicated cache in accordance with a destaging plan. For example, a newly written extent may be destaged based on aging. All extents may be flushed from the dedicated cache following host server reboot. All extents associated with a particular production volume may be flushed from the dedicated cache in response to a sync message from a storage array.

Abstract: Preventing timeouts of I/O requests at a data storage system that are associated with cloud-based and/or external data storage systems. Rather than allow a timeout to occur, a response is sent to the host at a predetermined time before timeout, which will prevent the timeout from occurring and may cause the host system to “retry” the I/O operation by issuing another I/O request specifying the same I/O operation. The data storage system may repeat this process a preconfigured number of times or indefinitely, or until the host or user terminates or the application crashes. An I/O request received from a host may be configured in accordance with one or more SAN- or NAS-based protocols, and the I/O request may be translated into an I/O request conforming to one or more cloud-based and/or Internet-based protocols and transmitted to a cloud-based and/or external storage system.

Abstract: The system, devices, and methods disclosed herein relate to using historic data storage system utilization metrics to automate data expansion capacity. In some embodiments, the data storage system is a RAID cloud having a plurality of storage devices divided into logical slices, also called splits. Methods disclosed herein allow user defined thresholds to be set wherein the thresholds control when data storage will be expanded. Data storage expansion capacity can be based upon historic usage criteria or customer-based criteria. Additional system customizations include user control over rebalancing data distribution as well as determining when system performance should be routinely evaluated offline.

Abstract: Techniques for obtaining consistent read performance are disclosed that may include: receiving measured read I/O (input/output) response times for flash storage devices; and determining, in accordance with a specified allowable variation, whether a first of the measured read I/O response times for a first of the flash storage devices is inconsistent with respect to other ones of the measured read I/O response times. Responsive to determining the first measured read I/O response time is inconsistent first processing may be performed that corrects or alleviates the inconsistency of the first measured read I/O response time. The first processing may include varying the first measured read I/O response time of the first flash storage device by enforcing, for the first flash storage device, a write I/O workload limit a read I/O workload limit and an idle capacity limit. Data portions may be ranked and selected for data movement based on read workload, write workload or idle capacity.

Abstract: Described is storage system and method for reducing power consumption. The storage system has first and second physical disks configured to provide mirroring. The first physical disk is placed into a power-saving mode of operation, while the second physical disk is in an active mode of operation responding to read and write requests. The first physical disk transitions from the power-saving mode of operation to an active mode of operation for destaging writes pending from cache to the first physical disk, while the second physical disk responds to read and write requests. The second physical disk transitions from the active mode of operation to the power-saving mode of operation, while the first physical disk responds to read and write requests.

Abstract: A catalog of services defines which storage-related services are applied to each service level of storage where storage capacity is managed and allocated in terms of chunks of capacity at different service levels. Each service level is defined based on one or more of tiered storage policy settings, drive size, drive speed, drive count, RAID protection, engine fractions, bandwidth and availability and characterized by one or more performance capabilities. Examples of services in the catalog include but are not limited to mobility, availability, continuity, and recovery services. Any combination of services, or no services at all, can be associated with a given service level of storage. Services may be performed at different performance levels. Further, services may be provided on-demand and billed on a usage basis.

Abstract: Techniques are described providing secure authentication of control commands executed on a data storage system. A pass code may be generated in accordance with criteria in response to successful two-factor authentication of a user identifier. Providing a valid generated passcode may be required with a control command in order for a data storage system to execute the control command. The control command may be one of a subset of possible control command that may be performed with respect to storage entities, such as logical devices and snapshots thereof. In another embodiment, rather than providing a pass code, the two factor authentication information and user identifier may be provided with the control command whereby successful completion of two-factor authentication of the user identifier and two factor authentication information may be required in order to execute the control command.

Abstract: A catalog of services defines which storage-related services are applied to each service level of storage where storage capacity is managed and allocated in terms of chunks of capacity at different service levels. Each service level is defined based on one or more of tiered storage policy settings, drive size, drive speed, drive count, RAID protection, engine fractions, bandwidth and availability and characterized by one or more performance capabilities. Examples of services in the catalog include but are not limited to mobility, availability, continuity, and recovery services. Any combination of services, or no services at all, can be associated with a given service level of storage. Services may be performed at different performance levels. Further, services may be provided on-demand and billed on a usage basis.

Abstract: Determining whether to compress data of a virtual storage unit based at least in part on: an I/O activity value of a virtual storage unit; a compressibility value of the virtual storage unit; and/or a capacity utilization of the storage system or a component thereof. For example, decision logic may be configured based on one or more of such parameters such that virtual storage units with relatively high I/O activities are rarely or never compressed, e.g., to avoid the disproportionately high increases in CPU and bandwidth resource consumption and I/O latency this could create. Decision logic may be configured such that, in general, the likelihood that a virtual storage unit will be compressed increases as: the I/O activity of the virtual storage unit decreases; the system capacity utilization increases; and/or as the compressibility value of the virtual storage unit increases.

Abstract: Identifying data for placement in a storage system having a plurality of storage classes includes subdividing the data into portions, for each of the portions, independently determining at least one score for a particular portion based on a metric corresponding to access of the particular portion, where the at least one score for the particular portion is independent of scores for other ones of the portions, and identifying sub-portions of data for placement in a particular storage class based on the at least one score of a portion of data corresponding to the sub-portions. The at least one score may be based on short term access statistics and long term access statistics. The access statistics may include read misses, writes, and prefetches.

Abstract: Described are techniques for processing service level objectives. A first service level objective specified for a storage group of devices may include a first value denoting a first target level of performance for I/O operations. A second service level objective specified for a first portion of the storage group may include a second value denoting a second target level of performance for I/O operations directed to the first portion. The second value may denote a higher level of performance than the first value. It may be determined whether there is a violation of any of the first service level objective and the second level objective. Responsive to determining there is the violation of any of the first service level objective and the second level objective, one or more data movements in accordance with the violation may be performed.

Abstract: Described are techniques for evaluating data movement alternative. A set of criteria including capacity and performance limits is received. First processing is performed to evaluate a plurality of alternatives for use in data movement with respect to a set of logical devices having data stored on a set of physical storage devices. Each of the plurality of alternatives includes a different set of data movement criteria comprising capacity limits and a different set of performance limits. The set of physical storage devices includes at least a first physical device of one of a plurality of storage tiers and a second physical device of another one of the plurality of storage tier. One of the sets of performance limits is selected in accordance with the first processing.