Efficient token management in a storage system

Patent metadata

Field	Value
Publication number	US-2022027059-A1
Application number	US-202016938272-A
Country	US
Kind code	A1
Filing date	Jul 24, 2020
Priority date	Jul 24, 2020
Publication date	Jan 27, 2022
Grant date	—

Abstract

At least one processing device receives a create-token command from a host device. Responsive to receipt of the create-token command, the processing device creates the token, generates an in-memory snapshot of data in one or more logical address ranges of one or more source storage volumes, associates the in-memory snapshot with the token, and provides the token to the host device. The processing device receives a write-via token command from the host device, the write-via-token command specifying the token and one or more logical address ranges of one or more target storage volumes. Responsive to receipt of the write-via-token command, the processing device determines whether or not differential metadata of the storage system includes one or more entries for the one or more logical address ranges of the one or more source storage volumes, and controls execution of the write-via-token command based at least in part on the determination.

First claim

1 . An apparatus comprising:
at least one processing device comprising a processor coupled to a memory; the at least one processing device being configured: to receive a create-token command from a host device, the create-token command specifying one or more logical address ranges of one or more source storage volumes of a storage system; responsive to receipt of the create-token command, to create the token, to generate an in-memory snapshot of data in the one or more logical address ranges of the one or more source storage volumes, to associate the in-memory snapshot with the token, and to provide the token to the host device; to receive a write-via token command from the host device, the write-via-token command specifying the token and one or more logical address ranges of one or more target storage volumes; and responsive to receipt of the write-via-token command, to determine whether or not differential metadata of the storage system includes one or more entries for the one or more logical address ranges of the one or more source storage volumes, and to control execution of the write-via-token command based at least in part on the determination; wherein the differential metadata of the storage system comprises at least one metadata delta log comprising one or more delta log buffers each comprising one or more delta log records.

2 . The apparatus of claim 1 wherein the at least one processing device comprises a storage controller of the storage system.

3 . The apparatus of claim 1 wherein the one or more target storage volumes are part of the same storage system that includes the one or more source storage volumes.

4 . The apparatus of claim 1 wherein the create-token command and the write-via-token command comprise respective Offloaded Data Transfer (ODX) commands.

5 . The apparatus of claim 1 wherein the in-memory snapshot is not subsequently persisted in one or more back-end storage devices of the storage system.

6 . (canceled)

7 . The apparatus of claim 1 wherein the storage system implements an in-memory transactional cache in which input-output operations and storage system management operations are persisted as part of a chronological journal.

8 . The apparatus of claim 7 wherein generating the in-memory snapshot of data in the one or more logical address ranges of the one or more source storage volumes comprises generating the in-memory snapshot within the in-memory transactional cache.

9 . The apparatus of claim 1 wherein responsive to receipt of a write operation directed to at least one logical address within the one or more logical address ranges of the one or more source storage volumes for which the token was created, a corresponding entry is generated in a metadata delta log of the differential metadata.

10 . The apparatus of claim 1 wherein controlling execution of the write-via-token command based at least in part on the determination comprises, responsive to the determination being affirmative, utilizing metadata from the one or more entries in the execution of the write-via-token command.

11 . The apparatus of claim 1 wherein determining if differential metadata of the storage system includes one or more entries for the one or more logical address ranges of the one or more source storage volumes comprises:
initiating an operation for copying of metadata for the one or more logical address ranges of the one or more source storage volumes from the in-memory snapshot to the one or more target storage volumes; and
determining in conjunction with the copying whether or not at least a portion of the metadata is in one or more metadata delta logs of the differential metadata.

12 . The apparatus of claim 11 wherein controlling execution of the write-via-token command based at least in part on the determination comprises:
responsive to at least a portion of the metadata being in one or more metadata delta logs of the differential metadata, utilizing that portion of the metadata in the one or more metadata delta logs in the copying; and
copying remaining portions of the metadata from the in-memory snapshot to the one or more target storage volumes.

13 . The apparatus of claim 8 wherein responsive to the transactional cache reaching a designated fullness level, the in-memory snapshot is destaged from the transactional cache to one or more back-end storage devices of the storage system and designated for use only in conjunction with execution of one or more write-via-token commands.

14 . The apparatus of claim 8 wherein responsive to the transactional cache reaching a designated fullness level, the in-memory snapshot is deleted and the token is invalidated.

15 . A computer program product comprising a non-transitory processor-readable storage medium having stored therein program code of one or more software programs, wherein the program code when executed by at least one processing device causes the at least one processing device:
to receive a create-token command from a host device, the create-token command specifying one or more logical address ranges of one or more source storage volumes of a storage system; responsive to receipt of the create-token command, to create the token, to generate an in-memory snapshot of data in the one or more logical address ranges of the one or more source storage volumes, to associate the in-memory snapshot with the token, and to provide the token to the host device; to receive a write-via token command from the host device, the write-via-token command specifying the token and one or more logical address ranges of one or more target storage volumes; and responsive to receipt of the write-via-token command, to determine whether or not differential metadata of the storage system includes one or more entries for the one or more logical address ranges of the one or more source storage volumes, and to control execution of the write-via-token command based at least in part on the determinations wherein the differential metadata of the storage system comprises at least one metadata delta log comprising one or more delta log buffers each comprising one or more delta log records.

16 . The computer program product of claim 15 wherein the storage system implements an in-memory transactional cache, and further wherein generating the in-memory snapshot of data in the one or more logical address ranges of the one or more source storage volumes comprises generating the in-memory snapshot within the in-memory transactional cache.

17 . The computer program product of claim 15 wherein controlling execution of the write-via-token command based at least in part on the determination comprises, responsive to the determination being affirmative, utilizing metadata from the one or more entries in the execution of the write-via-token command.

18 . A method comprising:
receiving a create-token command from a host device, the create-token command specifying one or more logical address ranges of one or more source storage volumes of a storage system; responsive to receipt of the create-token command, creating the token, generating an in-memory snapshot of data in the one or more logical address ranges of the one or more source storage volumes, associating the in-memory snapshot with the token, and providing the token to the host device; receiving a write-via token command from the host device, the write-via-token command specifying the token and one or more logical address ranges of one or more target storage volumes; and responsive to receipt of the write-via-token command, determining whether

Assignees

• Emc Ip Holding Co Llc

Inventors

• Chen Xiangping
• Meiri David

Classifications

• G06F11/1474

  in transactions (updating of structured data in databases G06F16/23) · CPC title

• G06F11/1435

  using file system or storage system metadata · CPC title

• G06F2201/84

  Using snapshots, i.e. a logical point-in-time copy of the data · CPC title

• G06F3/0608

  Saving storage space on storage systems · CPC title

• G06F3/0614

  Improving the reliability of storage systems · CPC title