Emc Corporation

Emc IP Holding Company LLC

Renen Hallak

Kobi Luz

Yaron Segev

Kirill Shoikhet

Shahar Frank

Erez Webman

Tal Ben-Moshe

Ehud Rokach

Ronen Kalish

Niko Farhi

Irit Yadin-Lempel

Ido Halevi

Eli Dorfman

Irit Yadin Lempel

Phil Love

Tal Ben Moshe

Example embodiments of the present invention relate and a method and an apparatus for managing a short hash handle. The method including receiving an I/O including a first identifier for a data block and examining the first identifier in comparison with a second identifier. The data block identified in the I/O then may be managed according to the first identifier and the second identifier.

Method and apparatus for creating a short hash handle highly correlated with a globally-unique hash signature

A memory management system for a thinly provisioned memory volume in which a relatively larger virtual address range of virtual address blocks is mapped to a relatively smaller physical memory comprising physical memory blocks via a mapping table containing entries only for addresses of the physical memory blocks containing data. The memory management system comprises a snapshot provision unit to take a given snapshot of the memory volume at a given time, the snapshot comprising a mapping table and memory values of the volume, the mapping table and memory values comprising entries only for addresses of the physical memory containing data. The snapshot is managed on the same thin provisioning basis as the volume itself, and the system is particularly suitable for RAM type memory disks.

Snapshot mechanism

In one aspect, a method includes receiving a request to write to an offset in a first logical device, determining a second logical device that wrote to the offset, the second logical device being an ancestor of the first logical device in a hierarchical tree of snapshots, determining from decedents of the second logical device in the hierarchical tree whether data in the offset of the second logical device is shadowed data or partially shadowed data, removing address-to-hash mapping for the offset of the second logical device if the data for the offset is shadowed and moving address-to-hash mapping to a single descendent of the second logical device if the data for the offset is partially shadowed.

Snapshot efficiency

A CAS data storage method and apparatus comprising: receiving input data including a succession of data items with corresponding logical addresses at a source CAS data storage space for storage therein and for replication at a destination CAS data storage space, generating a hash key for each data item at the source storage space, comparing respective hash keys with hash keys stored at a hash key storage table, to determine whether respective further data items are already present at the destination storage device; transferring respective data items to the destination storage space if no match is made to a hash key stored at the hash key storage table, but not transferring respective further data items if a match is made to a hash key stored at the hash key storage table, thereby transferring to the destination storage space only unique data items.

Low latency replication techniques with content addressable storage

A redundant array of independent disk (RAID) memory storage system comprising data storage blocks arranged in a first plurality of data rows and a second plurality of data columns, wherein parity data is stored in additionally defined parity blocks, and wherein numbers of data blocks in respective columns are different, to accommodate the additional diagonal parity data block that the geometry of the system requires. The system is suitable for an SSD array in which sequential disk readout is not required.

Method and system for storing data in raid memory devices

In one aspect, a method includes providing a server that stores a hash digest metadata table and configuring entries in the hash digest metadata table to include entries that include persistent fields and non-persistent fields. The hash digest metadata table maps a hash digest representing X-Page data to its metadata information. The persistent fields include a short hash digest field, a physical layout offset field, a deduplication reference count field and a flags field.

Data structure for hash digest metadata component

In one aspect, a method includes receiving and recording journal data at a client on a first server, providing the data to a journal component, transferring the journal data from the journal component to a reserve memory in a memory of a second server using a remote direct memory access (RDMA), after failure of the client, retrieving the journal data from the reserve memory using the RDMA and replacing the journal data lost from the failure of the client with the journal data from the reserve memory.

Backing up journal data to a memory of another node

In one aspect, a method includes receiving hash signature, determining if there is an existing hash signature that matches the hash signature received, determining if there is an existing short hash handle that matches the hash signature received, designating n-1 least significant bits of the hash signature to be n-1 least significant bits of a n-bit short hash handle if there is not an existing short hash handle that matches the hash signature received and adding a hash handle bit to the n-1 bits to form the n-bit short hash handle.

Generating a short hash handle

A device for scalable block data storage and retrieval uses content addressing. Data storage devices store data blocks, and are connected over a network to computing modules. The modules comprise control modules and data modules and carry out content addressing for both storage and retrieval. The network defines separate control paths via the control modules and data paths via the data modules.

Scalable block data storage using content addressing

In one aspect, a redundant array of independent disk (RAID) memory storage system includes a plurality of data storage disks comprising data blocks, a first redundancy storage disk comprising parity blocks that are a parity by row of the data blocks in the data storage disks, a second redundancy storage disk comprising parity blocks storing parities of diagonals of the data blocks in the data storage disks, a third redundancy storage disk comprising parity blocks storing parities of diagonals of the data blocks in the data storage disks and circuitry configured to recover data from three failed storage disks.

Growing community of inventors

Sde Warburg, Israel

Renen Hallak