Emc IP Holding Company LLC

Wayne Li

Jian Gao

Jibing Dong

Geng Han

Hongpo Gao

Jamin Jianbin Kang

Shaoqin Gong

Lili Chen

Ree Sun

Xinlei Xu

Huadong Li

Jianbin Kang

Sheng Wang

Tao Xu

Michael P Wahl

Ilya Usvyatsky

Charles Ma

A method of initializing a data storage system (DSS) is provided. The method includes (a) in response to the DSS booting, reading data from a first plurality of disks marked as part of a raw mirror which mirrors configuration data of the DSS between the first plurality of disks; (b) comparing sequence numbers from the read data read and selecting data from a disk of the first plurality having a latest sequence number; (c) obtaining configuration data of the DSS from the selected data; (d) using the configuration data to construct a topology of the DSS which includes information describing a relationship between a second plurality of disks of the DSS, RAID groups of the DSS, and logical disks presented to users, the second plurality of disks being larger than and including the first plurality of disks; and (e) initializing the RAID groups and the logical disks described by the topology based on the information of the topology.

Using a raw mirror to initialize a storage system

In a method and apparatus for storage management, a method includes: creating a plurality of profiles for address mapping, the profiles comprising a part of mapping relation in the total mapping table and creating an index for a part of the plurality of profiles to accelerate the lookup speed. A corresponding device and computer program product are also disclosed.

Method and device for storage management

Embodiments of the present disclosure provide a method of managing a disk pool, the disk pool having a plurality of disks which are divided into a plurality of disk extents, the method comprising: determining the number of input/output (I/O) requests for disk extents in the disk pool within a predetermined period of time; determining respective hotness of the disk extents based on the number of I/O requests; determining hotness of the disks based on the hotness of the disk extents; and determining migration of data in the disk extents based on the hotness of the disk.

Method and device for managing disk pool

Implementations of the present disclosure relate to a method, system and computer program product for managing a storage system. Specifically, in one implementation of the present disclosure there is provided a method for managing a storage system. The method comprises: determining an access level of a target extent comprised in a stripe of a storage system, the access level indicating the possibility that the target extent will be accessed; obtaining a usage state of a target storage device where the target extent resides, the target storage device residing in a storage device pool associated with the storage system; and processing a mapping relationship between the target extent and the target storage device on the basis of the access level and the usage state. In other implementations of the present disclosure, there is provided a corresponding system and computer program product.

Method, system and computer program product for managing storage system

Techniques are disclosed for managing data storage. In one embodiment, the techniques determine one or more RAID extents having a disk extent supported by an extent of storage on a storage device in an inoperative state. Each of the RAID extents contains a respective set of disk extents allocated to that RAID extent and each disk extent is supported by an extent of storage on a storage device of the set of storage devices. The techniques also comprise evaluating a set of values, wherein each value indicates, for a corresponding pair of storage devices from the set of storage devices, a number of RAID extents which contain disk extents belonging to both storage devices of the pair. The techniques also comprise selecting, based on the said evaluation and for each of the one or more RAID extents, a free disk extent for facilitating rebuild of that RAID extent, wherein the said free disk extent is supported by an extent of storage of one of the set of storage devices other than one of the storage devices associated with that RAID extent.

Method, apparatus and computer program product for managing data storage in data storage systems

Embodiments of the present disclosure relate to a method, a device and a computer readable medium for managing a storage system. The method can determine a mapping between a logical storage extent and a plurality of storage devices in a storage pool without storing a table of the mapping. Further, the method can record a new mapping after a storage devices fails and restore the original mapping after the failed storage device is replaced.

Mapping logical blocks of a logical storage extent to a replacement storage device

In response to detecting that a total number of physical data storage drives in a group of physical data storage drives exceeds a maximum drive group size, the group of physical data storage drives is divided into a multiple partnership groups, and RAID extents in a RAID mapping table are divided into multiple RAID extent groups. Each one of the RAID extent groups contains multiple RAID extents and corresponds to one of the partnership groups of physical data storage drives. The RAID extents in each RAID extent group only indicate physical data storage drives contained in the corresponding partnership group of physical data storage drives, in order to ensure that data recovery and RAID extent rebuilding after a drive failure involve only the physical data storage drives within the same partnership group as the failed physical data storage drive.

Splitting a group of physical data storage drives into partnership groups to limit the risk of data loss during drive rebuilds in a mapped RAID (redundant array of independent disks) data storage system

Embodiments of the present disclosure provide a method and an apparatus for storage management. For example, there is provided a method comprising: creating a plurality of profiles for address mapping, the profiles comprising a part of mapping relation in the total mapping table and creating an index for a part of the plurality of profiles to accelerate the lookup speed. A corresponding device and computer program product are also disclosed.

Embodiments of the present disclosure provide a method of managing a redundant array of independent disks (RAID) system and an electronic device. The method includes configuring a plurality of disks in the RAID system as a raw mirror for storing configuration data of the RAID system; storing metadata for the raw mirror in the plurality of disks, the metadata stored in each of the plurality disks including an identifier identifying that the disk belongs to the raw mirror and a sequence number identifying a writing operation for a block storing the metadata in the disk; and controlling reading and writing of the raw mirror based on the metadata.

Operating a raw mirror within a RAID system

Embodiments of the present disclosure provide a method and device for storage management. For example, there is proposed a method comprising: in response to a plurality of storage devices in a storage system being to be allocated to an unallocated logic storage area, determining a plurality of allocation schemes for allocating the plurality of storage devices to the unallocated logic storage area; obtaining allocation uniformity of the plurality of storage devices with respect to an allocated logic storage area of the storage system; and selecting one of the plurality of allocation schemes at least based on the allocation uniformity, such that the uniform degree of the allocation has a minimum variation. Corresponding device and computer program product are also disclosed.

Method and apparatus for storage device allocation

A method is performed by an extent pool manager running on a data storage device. It is configured to manage assignment of disk extents provided by a pool of drives to a set of mapped RAID extents. The method includes (a) receiving an indication that a particular drive has triggered an end-of-life (EOL) condition based on an error count of that drive and a standard sensitivity setting, (b) in response to receiving the indication, changing a sensitivity setting of other drives to be less sensitive than the standard sensitivity setting, and (c) remapping disk extents from the particular drive to the other drives of the pool while the other drives continue operation using the changed sensitivity setting. An apparatus, system, and computer program product for performing a similar method are also provided.

Adjustable error sensitivity for taking disks offline in a mapped RAID storage array

Techniques for allocating mapped RAID extents of a RAID group may include: determining a pool of N physical storage devices; selecting M physical storage portions, wherein each of the M physical storage portions is selected from a different one of the N physical storage devices of the pool; and allocating a first mapped RAID extent as the selected M physical storage portions. The first mapped RAID extent may denotes a stripe of the RAID group. Physical storage portions for each mapped RAID extent may be selected from the N physical storage devices with a goal of maintaining even distribution of the selected portions among the N physical storage devices. Such selection may use a neighborhood matrix and a subset of all possible combinations of M physical storage devices that may be selected from the N physical storage devices.

Extent selection with mapped raid

A mapped RAID group is generated that contains multiple RAID extents, and each one of the RAID extents is configured and arranged to indicate multiple drive extents that are each a contiguous region of non-volatile data storage in a physical drive. The RAID extents are divided into equal size subsets based on a requested RAID width. Drive extents are allocated from a drive extent pool such that the drive extents indicated by RAID extents contained in the same subset are all allocated from different ones of the physical drives. Logical block rotation is performed between the storage object and the mapped RAID group, causing host data written to consecutive blocks of the storage object address space to be directed to different ones of the RAID extents in the mapped RAID group. Data mirroring is performed between drive extents contained within each of the individual RAID extents of the RAID group.

Providing Raid-10 with a configurable Raid width using a mapped raid group

A data storage system creates, maintains and utilizes logical storage structures including (1) a pool of device extents on user devices, organized into data portions of mapped RAID groups each having a data portion and a RAID group metadata element having (i) a basic portion and (ii) a mapping portion mapping each set of device extents to logical RAID extents per RAID type, (2) a pool logical device (e.g., an internal mapped RAID) in the pool, storing the mapping portions of the metadata elements of the mapped RAID group, and (3) a system logical device on separate system devices, storing (i) the basic portions of the metadata elements of the RAID groups, and (ii) a pool metadata element including a pool mapping portion for the pool logical device.

Data storage system with multi-level, scalable metadata structure

Techniques detect non-uniform distributions of RAID extents across the storage drives of a data storage appliance and rebalance the allocation of disk extents of the storage drives amongst the RAID extents. The improved techniques prevent the distribution of RAID extents across the storage drives of a mapped RAID system from becoming overly non-uniform.

Growing community of inventors

Beijing, China

Wayne Li