Abstract: A networked data storage system includes data movement logic and a virtual machine for executing a data management processing plan which is generated by a facility outside the storage array based on statistical information associated with extent level activity metrics provided by the storage array. Dynamically updated and automatically generated data management processing plans are provided to the storage array in the form of units of compiled byte code which the storage array is able to verify and execute using a virtual machine. The virtual machine interfaces with the environment in which it is embedded in a carefully constrained manner, thereby preventing clearly undesirable operations.

Abstract: Techniques are described for processing a data operation that writes first data to a data portion currently stored on first physical storage of a first storage tier of a data storage system, including storage tiers each having a different performance ranking relative to other storage tiers. Second physical storage is allocated from one of the storage tiers for storing the first data written to the data portion. This one storage tier is selected independent of the first storage tier. The first data is stored in a cache and destaged from the cache to the second physical storage. A single merged copy of data for the data portion is formed. Based on an activity level of the data portion, a target tier is selected for storing the single merged copy of data for the data portion.

Abstract: Described are techniques for redistributing workload. A first port, from which a first workload is to be redistributed, is selected. A second port, having available capacity to perform additional workload, is selected. A device, accessible over both the first port and the second port, is selected. Each of one or more paths including the first port is set to a passive state for the device. Each of the one or more paths having the passive state for the device indicates to a client that sends I/O operations to the device that said each path is not to be used for sending I/O operations to said device and that said each path is available for use in performing control operations directed to the device.

Abstract: Described are techniques for enforcing an allocation policy. Information is received that describes one or more storage groups. Each of the storage groups includes one or more thin devices. Each of the thin devices includes a plurality of chunks of storage allocated on one or more of a plurality of storage tiers. For each of the one or more storage groups, a plurality of counters is determined indicating amounts of storage currently allocated from the plurality of storage tiers for use by the storage group. Using the plurality of counters, it is determined whether each of the one or more storage groups violates thresholds included in an allocation policy associated with each storage group. Each of the thresholds specifies a maximum amount of storage of one of the plurality of storage tiers that can be used by each storage group.

Abstract: Described are techniques for performing data storage optimizations. A data storage optimizer on a first data storage system connected to a set of other data storage systems receives performance classification information. The first data storage system includes a first set of storage devices of a first performance classification. The set of other data storage systems includes a second set of storage devices of a second performance classification different from the first performance classification. A write operation is received from the host to write first data to a target address of a virtually provisioned device. It is determined that physical storage is not currently allocated for the target address of the virtually provisioned device. A first portion of physical storage is allocated for storing the first data. The first portion of physical storage is included in a storage device of the second set having the second performance classification.

Abstract: A method for receiving a Mode Select command concerning a LUN from a host. The Mode Select command defines control information and host identifier information concerning the host associated with the Mode Select command. The Mode Select command is processed to determine if the control information included within the Mode Select command signifies an intent by the host to relinquish control of the LUN. If the control information signifies an intent to relinquish control of the LUN, the host identifier information included within the Mode Select command is processed to confirm that it matches LUN control identifier information that defines the host that currently controls the LUN. If the host identifier information matches the LUN control identifier information, at least the control information included within the Mode Select command is written to a buffer associated with the LUN. The buffer includes a control field and a GUID field.

Abstract: A method, computer program product, and computing system for receiving a Mode Select command concerning a logical unit number (LUN) from a first host, wherein the Mode Select command defines control information and host identifier information concerning the first host, and the LUN is currently being controlled by a second host. The Mode Select command is processed to determine if the control information and host identifier information included within the Mode Select command signifies an intent by the first host to seize control of the LUN from the second host. If the control information and host identifier information signifies an intent to seize control of the LUN from the second host, the control information and host identifier information included within the Mode Select command is written to a buffer associated with the LUN, wherein the buffer includes a control field and a globally unique identifier (GUID) field.

Abstract: A method, computer program product, and computing system for identifying compressed content within a first cache system to a data array associated with the first cache system. Related content is located on the data array that is associated with the compressed content on the first cache system and it is determined whether the related content on the data array is compressible.

Abstract: A method, computer program product, and computing system for receiving a Mode Select command concerning a single LUN from each of a plurality of potential hosts. Each Mode Select command defines control information and host identifier information concerning the potential host associated with the Mode Select command. The received Mode Select commands are processed serially and in accordance with the order in which the Mode Select commands were received. The first Mode Select command received is accepted and subsequent Mode Select commands received are rejected, thus defining an accepted Mode Select command and one or more rejected Mode Select commands. The control information and host identifier information included within the accepted Mode Select command are written to a buffer associated with the single LUN. The buffer includes a control field and a GUID field.

Abstract: Described are techniques for tracking activity for one or more devices. Each of the one or more devices is partitioned into one or more extents. Each of the one or more extents includes a plurality of sub extents. Each of the sub extents includes a plurality of chunks. For each of said one or more extents of each of said one or more devices, extent activity level information is determined including one or more metrics indicating an activity level for said each extent; and For each of said one or more extents of each of said one or more devices, an activity bitmap is determined. The activity bitmap includes an entry for each sub extent included in said each extent, said entry indicating an activity level for said each sub extent.

Abstract: Described is data storage system modeling. Received at a first data storage system is information representing a workload for I/O operations directed to a logical devices having storage provisioned on physical devices of a second data storage system. Information representing the workload may be obtained by performing discovery processing to discover performance characteristics of the physical devices of the second data storage system. Discovery processing may include receiving, at the first data storage system, I/O operations from a client directed to the set of one or more logical devices having storage provisioned on the physical devices of the second data storage system. The I/O operations are then issued to the second data storage system. In response, performance data is obtained at the first data storage system representing the workload for the plurality of I/O operations. Performance of the second data storage system is modeled in accordance with the workload.

Abstract: Synchronization of data layouts and resource utilizations at one or more remote replica sites with the workload and data tiering decisions being made at the primary site allows for an efficient and effective workload support transfer in the event of site failover from a primary site to a remote site. Relevant data access information about workload being supported at the primary site is collected and from that raw information, characterized data access information is generated that condenses the raw data access information or otherwise provides relevant encapsulated information about the raw data access information. The characterized data access information is transmitted to the one or more remote sites allowing each remote site to make its own independent decisions on how best to utilize its available resources to match the performance requirements currently being supported by the primary site.

Abstract: A method, computer program product, and computing system for determining at least one LUN that was being controlled by a host prior to a crash event concerning the host, thus define at least one target LUN. A Mode Select command is prepared for the at least one target LUN, wherein the Mode Select command defines control information and host identifier information concerning the host. The Mode Select command is processed to determine if the control information and host identifier information included within the Mode Select command matches control information and host identifier information included within a buffer associated with the at least one target LUN. If the control information and host identifier information included within the Mode Select command matches the control information and host identifier information included within the buffer, control of the at least one target LUN is granted to the host.

Abstract: A method for processing a write instruction for writing data to a database stored on a logical device includes obtaining first and second addresses that specify the location of the data in respective first and second address spaces. A third address corresponding to an expected location of the data record in the first address space is then calculated. On the basis of a comparison between the first address and the third address, a determination is made as to whether to execute the write instruction.

Abstract: Measuring access rates of a computer memory include subdividing the memory into subsections, monitoring access rates for each of the subsections, in response to a subsection having a relatively high access rate, subdividing the subsection into multiple subsections that are separately monitored, and, in response to at least two adjacent subsections having a relatively low access rate, merging the at least two subsections into a single subsection. Monitoring access rates may include monitoring at least one of the following operational parameters: number of data accesses, number of cache accesses, number of cache misses, number of read accesses, number of write accesses, and ratio of read accesses to write accesses. Two or more operational parameters may be used and the operational parameters may be weighted.

Abstract: A partitioned storage subsystem includes a plurality of directors, each having at least one processor thereon, each of the directors acting as one of: a primary director and a secondary director for a subset of logical devices handled by the partitioned storage subsystem, where primary directors actively perform I/O operations for logical devices and wherein secondary directors receive data to mirror memory of a corresponding primary director. The partitioned storage subsystem also includes a global memory distributed among the plurality of directors, where a different portion of the global memory is provided on each of the directors, and includes metadata for the logical devices, provided in the global memory, where the metadata contains information that correlates logical device data with physical device data. The physical device data may be provided by at least one disk drive coupled to at least one of the directors.

Abstract: A storage array includes a plurality of directors, each having at least one processor thereon and a global memory distributed among the plurality of directors. A different portion of the global memory is provided on each of the directors. A interconnect fabric is coupled to each of the directors. Global memory accesses performed by one director to access memory of another director through the interconnect fabric. The storage array also includes a plurality of partitioned storage subsystems, each including a separate subset of the directors, where each of the partitioned storage subsystems handles I/O operations for a plurality of logical devices independently of I/O operations for logical devices of other ones of the partitioned storage subsystems, the I/O operations using metadata provided in the global memory of the corresponding directors and containing information that correlates logical device data with physical device data.

Abstract: Handling I/O operations for a storage array includes distributing metadata among separate memories of a plurality of directors of the storage array, where the metadata correlates logical device data with physical device data. A first one of the directors receives an I/O operation for a particular logical device. Handling I/O operations may also include determining which of the plurality of directors contains metadata corresponding to the particular logical device, and, in response to the metadata being on a different one of the directors, the first director providing a request to the different one of the directors. The directors may be interconnected by an interconnect fabric. The first one of the directors may provide a request to the second one of the directors via the interconnect fabric. Determining which of the plurality of directors contains metadata correspond to the particular logical device may include using a lookup table.

Abstract: A system for de-duplicating data includes providing a first volume including at least one pointer to a second volume that corresponds to physical storage space, wherein the first volume is a logical volume. A first set of data is detected as a duplicate of a second set of data stored on the second volume at a first data chunk. A pointer of the first volume associated with the first set of data is modified to point to the first data chunk. After modifying the pointer, no additional physical storage space is allocated for the first set of data.

Abstract: Described are techniques for prioritizing messaging traffic. A first message having a second message encapsulated in a payload of the first message is received. It is determined whether the first message meets one or more prioritization criteria in accordance with one or more portions of a payload of the second message.