Emc Corporation

Emc IP Holding Company LLC

Mark K Ku

Xiangping Chen

Philippe Armangau

Dennis Thomas Duprey

Khang Can

Qin Tao

Monica Chaudhary

Jean-Pierre Bono

David W Harvey

Dean D Throop

Manish Madhukar

Xiaoye Jiang

Kevin Bangyen Jiang

Karl M Owen

Richard P Ruef

Sorin Faibish

Miles Aram De Forest

Thomas Earl Linnell

Jiannan Zheng

Hongliang Tang

Dinesh Venkatesh

Rui Liang

Siyu Zhou

Sairam Iyer

Joseph B Shimkus

A method is used in managing data in a data storage system. A tiered storage pool is identified wherein the storage pool includes multiple tiers having multiple storage units. A wear indicator for each of the multiple storage units is monitored. A first storage unit having a wear indicator greater than a second storage unit is identified. High activity data on the first storage unit is also identified. The identified high activity data is migrated from the first storage unit to the second storage unit.

Managing data placement based on flash drive wear level

A method is used in managing data deduplication in storage systems based on storage space characteristics. Characteristics of first and second storage tiers are evaluated. A first data object resides on the first storage tier and a second data object resides on the second storage tier. The first and second data objects are selected for applying a deduplicating technique. A data storage system includes the first and second storage tiers configured such that performance characteristics associated with the first storage tier is different from the second storage tier. Based on the evaluation, the deduplicating technique is applied to the first and second data objects.

Managing data deduplication in storage systems based on storage space characteristics

A method is used in balancing I/O load on data storage systems. A slice is selected from a first storage container of a storage tier. The storage tier includes a second storage container. The slice is relocated from the first storage container of the storage tier to the second storage container of the storage tier, where I/O load of the first storage container is greater than I/O load of the second storage container.

Balancing I/O load on data storage systems

A method is used in managing storage space of storage tiers. Storage space utilization characteristics of a storage tier of a set of storage tiers in a storage system are evaluated. Based on the evaluation, reservation of headroom storage space in the storage tier is adjusted. The headroom storage space indicates an amount of the storage space reserved as unused storage space in the storage tier.

Managing storage space of storage tiers

A method is used in managing data deduplication in storage systems based on I/O activities. I/O activity of first and second data objects is evaluated. The first and second data objects are selected for applying a deduplicating technique. Based on the evaluation, the deduplicating technique is applied to the first and second data objects.

Managing data deduplication in storage systems based on I/O activities

A method is used in managing data deduplication in storage systems. Characteristics of first and second data objects are evaluated based on a set of deduplication policies. The first and second data objects are selected for deduplication. Based on the evaluation, deduplication performed on the first and second data objects is affected.

Managing data deduplication in storage systems

A method is used in managing deduplication density. A deduplication density of a data object is determined. The deduplication density is indicated by a number of deduplicated data objects represented by the data object. Based on the deduplication density of the data object, the data object is skipped for applying a deduplicating technique to the data object. An association is created between the data object and another data object. The other data object is used for applying the deduplicating technique where contents of the other data object are identical to contents of the data object.

Managing deduplication density

A method is used in managing deduplication density. A deduplication density of a data object is determined. The deduplication density is indicated by a number of deduplicated data objects represented by the data object. Based on the deduplication density of the data object, a deduplicating technique is applied to the data object.

A method is used in measuring data access activity. I/O data is analyzed that describes I/O activity for a slice of a logical volume. Based on the I/O data, a first value of data access activity is determined for the slice corresponding to a first time period, and a second value of data access activity is determined corresponding to a second time period. From the first and second values, an exponential moving average of data access activity is derived for the slice.

Measuring data access activity

A method is used in improving deduplication efficiency. Metadata of a data object is evaluated for determining write activity of the data object. Based on the write activity, deduplicating technique is applied to the data object.

Deduplication efficiency

Methods and apparatus for organizing a plurality of versions of a file in a file system. The plurality of versions of the file are stored in a data structure having a hierarchical organization that reflects relationships among the plurality of versions. Each version of the plurality of versions is assigned a name that identifies its position in the hierarchical organization. The hierarchical organization of the data structure and the descriptive naming convention used for the plurality of versions in the data structure facilitates deleting a version while retaining other versions derived from the version following the deletion of the version, and enables a staged initialization of the data structure upon system start-up.

Methods and apparatus for managing multiple point in time copies in a file system

Methods and systems are disclosed for relocating data in a physical storage pool comprising a plurality of storage tiers having differing performance characteristics, the physical storage pool being mapped into one or more logical units, each logical unit comprising a plurality of logical slices of data storage. The methods and systems can involve receiving a relocation list, the relocation list including, for each of a plurality of logical slices, a slice identifier, a temperature value, and a current physical location, determining a destination tier for each logical slice on the relocation list, evaluating for each logical slice on the relocation list a performance gain expected to be achieved by moving the logical slice from its current physical location to a new location in the destination tier, and relocating data in a logical slice from its current physical location to the new location based on the evaluation.

Automated data relocation among storage tiers based on storage load

A method is used in applying data access activity measurements. A slice relocation candidate list is generated which identifies slices to be relocated along with respective destination tier information. Slices in a pool are matched to respective matching tiers based on the slices' respective temperatures and tier preferences. Based on whether a current tier for a slice differs from the matching tier for the slice, the slice is listed in the relocation candidate list.

Applying data access activity measurements

A storage processor of a data storage system includes a data relocation task scheduler that provides system limit control on the execution of data relocation requests. The data relocation task scheduler also provides fairness and concurrency limit enforcement by scheduling relocation requests from different provisioning domains, such as storage pools, in a fair manner. For example, the data relocation task scheduler includes stackable sets of pending task queues that store incoming data relocation requests. The data relocation task scheduler applies an iteration scheme to remove data relocation requests from the pending task queues thereby providing scheduling fairness among the queues and among the different provisioning domains within the data storage system. The data relocation task scheduler is configured to receive updated policies that control both system-wide data relocation resource consumption and scheduling fairness among the queues during operation and dynamically adjust current policies with the updated policies.

Scheduling data relocation activities using configurable fairness criteria

A storage object such as a virtual disk drive or a raw logical volume is contained in a UNIX compatible file so that the file containing the storage object can be exported using the NFS or CIFS protocol and shared among UNIX and MS Windows clients or servers. The storage object can be replicated and backed up using conventional file replication and backup facilities without disruption of client access to the storage object. For client access to data of the storage object, a software driver accesses the file containing the storage object. For example, a software driver called a virtual SCSI termination is used to access a file containing a virtual SCSI disk drive. Standard storage services use the SCSI over IP protocol to access the virtual SCSI termination. An IP replication or snapshot copy facility may access the file containing the virtual SCSI disk drive using a higher-level protocol.

Growing community of inventors

Wollaston, MA, United States of America

Mark K Ku