CROSS REFERENCE TO RELATED APPLICATIONS

This application is related to co-pending U.S. patent application Ser. No. 10/157,006 entitled MANAGING INLINE DATA COMPRESSION IN STORAGE SYSTEMS filed on Dec. 29, 2016, which is incorporated herein by reference, co-pending U.S. patent application Ser. No. 10/156,993 entitled MANAGING INLINE DATA COMPRESSION IN STORAGE SYSTEMS filed on Dec. 29, 2016, which is incorporated herein by reference, and co-pending U.S. patent application Ser. No. 10/430,376 entitled MANAGING INLINE DATA COMPRESSION IN STORAGE SYSTEMS filed on Dec. 29, 2016, which is incorporated herein by reference.

BACKGROUND

Technical Field

This application relates to managing inline data compression in storage systems.

Description of Related Art

Computer systems may include different resources used by one or more host processors. Resources and host processors in a computer system may be interconnected by one or more communication connections. These resources may include, for example, data storage devices such as those included in the data storage systems manufactured by EMC Corporation. These data storage systems may be coupled to one or more servers or host processors and provide storage services to each host processor. Multiple data storage systems from one or more different vendors may be connected and may provide common data storage for one or more host processors in a computer system.

A host processor may perform a variety of data processing tasks and operations using the data storage system. For example, a host processor may perform basic system I/O operations in connection with data requests, such as data read and write operations.

Host processor systems may store and retrieve data using a storage device containing a plurality of host interface units, disk drives, and disk interface units. The host systems access the storage device through a plurality of channels provided therewith. Host systems provide data and access control information through the channels to the storage device and the storage device provides data to the host systems also through the channels. The host systems do not address the disk drives of the storage device directly, but rather, access what appears to the host systems as a plurality of logical disk units. The logical disk units may or may not correspond to the actual disk drives. Allowing multiple host systems to access the single storage device unit allows the host systems to share data in the device. In order to facilitate sharing of the data on the device, additional software on the data storage systems may also be used.

Such a data storage system typically includes processing circuitry and a set of disk drives (disk drives are also referred to herein as simply “disks” or “drives”). In general, the processing circuitry performs load and store operations on the set of disk drives on behalf of the host devices. In certain data storage systems, the disk drives of the data storage system are distributed among one or more separate disk drive enclosures (disk drive enclosures are also referred to herein as “disk arrays” or “storage arrays”) and processing circuitry serves as a front-end to the disk drive enclosures. The processing circuitry presents the disk drive enclosures to the host device as a single, logical storage location and allows the host device to access the disk drives such that the individual disk drives and disk drive enclosures are transparent to the host device.

Disk arrays are typically used to provide storage space for one or more computer file systems, databases, applications, and the like. For this and other reasons, it is common for disk arrays to be structured into logical partitions of storage space, called logical units (also referred to herein as LUs or LUNs). For example, at LUN creation time, storage system may allocate storage space of various storage devices in a disk array to be presented as a logical volume for use by an external host device. This allows a disk array to appear as a collection of separate file systems, network drives, and/or volumes. Disk arrays may also include groups of physical disks that are logically bound together to represent contiguous data storage space for applications.

Some data storage systems employ software compression and decompression to improve storage efficiency. For example, software compression involves loading compression instructions into memory and executing the instructions on stored data using one or more processing cores. A result of such software compression is that compressed data requires less storage space than the original, uncompressed data. Conversely, software decompression involves loading decompression instructions into the memory and executing the instructions on the compressed data using one or more of the processing cores, to restore the compressed data to its original, uncompressed form.

Other data storage systems perform compression and decompression in hardware. For example, a data storage system may include specialized hardware for compressing and decompressing data. The specialized hardware may be provided on the storage processor itself, e.g., as a chip, chipset, or sub-assembly, or on a separate circuit board assembly. Unlike software compression, which operates by running executable software instructions on a computer, hardware compression employs one or more ASICs (Application Specific Integrated Circuits), FPGAs (Field Programmable Gate Arrays), RISC (Reduced Instruction Set Computing) processors, and/or other specialized devices in which operations may be hard-coded and performed at high speed.

SUMMARY OF THE INVENTION

A method is used in managing inline data compression in storage systems. A request is received to flush data of a file system to a storage device of a storage system. A compression ratio is determined for writing the data to the storage device in a compressed format. Based on the determination, a number of allocation units is determined in which a segment is apportioned. The segment comprises of a set of allocation units in the compressed format. Based on the determination, the data is written to the segment in the compressed format.

