Method and apparatus for rapid volume reformatting

Patent metadata

Field	Value
Publication number	US-2020174710-A1
Application number	US-202016786802-A
Country	US
Kind code	A1
Filing date	Feb 10, 2020
Priority date	May 13, 2016
Publication date	Jun 4, 2020
Grant date	—

Abstract

A storage controller is provided. The storage controller includes circuitry configured to utilize a format command to change a storage volume coupled to the storage controller from a first format to a second format and memory configured to store a data structure for first and second format indications for the storage volume. The storage controller determines if a selected band is initialized to the second format, and if the selected band is not initialized to the second format, the storage controller initializes the selected band to the second format and updates the data structure to indicate the selected band is initialized to the second format.

First claim

1 . A storage controller, comprising:
circuitry configured to utilize a format command to change a storage volume coupled to the storage controller from a first format to a second format; and memory configured to store the format command and a data structure comprising a single high water mark address variable that always tracks a demarcation between bands in the first format and bands in the second format, the first format command resident in the memory and configured to be invoked by a user or application program configured to control the storage controller:
determining if a selected band is initialized to the second format, and in response to the storage controller determining the selected band is not initialized to the second format, the storage controller initializing the selected band to the second format; and
updating the data structure to indicate the selected band is initialized to the second format.

2 . The storage controller of claim 1 , wherein after determining if the selected band is initialized to the second format, the storage controller:
calculates if there are one or more additional bands of the plurality of bands to initialize to the second format, and in response:
chooses a next band of the plurality of bands to initialize,
wherein the next band was not previously initialized to the second format, wherein the storage controller repeats determines, initializes, updates, calculates, and chooses until all bands of the plurality of bands have been initialized to the second format, wherein if there are not one or more additional bands of the plurality of bands to initialize to the second format, the storage controller creates a notification that the storage volume is in the second format.

3 . The storage controller of claim 1 , wherein prior to issuing the format command to the storage volume, the storage controller:
initializes the data structure to a state identifying all bands of the plurality of bands as one of uninitialized and initialized to the first format.

4 . The storage controller of claim 1 , wherein the notification that the storage volume is in the second format comprises at least one of the storage controller:
creates an event in a management log; and notifies a user that initialization of the storage volume to the second format is complete.

5 . The storage controller of claim 1 , wherein the storage controller allows read and write access to the storage volume while the storage volume is being initialized to the second format.

6 . The storage controller of claim 5 , wherein if the storage controller receives a first write request to the selected band, the storage controller:
determines whether the selected band is either in the first format and initialization to the second format has not been started, currently being initialized to the second format, or previously initialized to the second format, wherein if the storage controller determines the selected band is in the first format and initialization to the second format has not been started, the storage controller:
locks the selected band;
writes data corresponding to the first write request to logical block addresses of the selected band corresponding to the first write request; and
initializes data of the selected band having logical block addresses that do not correspond to the first write request,
wherein in response to the storage controller determining the selected band is currently being initialized to the second format, the storage controller:
delays the first write request to the selected band until the initialization of the selected band to the second format is completed,
wherein if the storage controller determines the selected band was previously initialized to the second format, the storage controller:
completes the first write request to the selected band.

7 . The storage controller of claim 5 , wherein if the storage controller receives a read request to the selected band while the selected band is being initialized to the second format, the storage controller either:
provides predetermined read data in response to the read request; or waits to provide read data until initialization of the selected band to the second format is completed.

8 . The storage controller of claim 1 , wherein one of:
the first format comprises one of unformatted, no Protection Information (PI), and a different type of Protection Information (PI) from the second format, and the second format comprises Protection Information (PI); and the first format comprises Protection Information (PI) and the second format comprises no Protection Information (PI).

9 . A method comprising:
issuing, by a hardware storage controller, a format command changing a storage volume from a first format to a second format; selecting a band of the storage volume to initialize; determining, by the hardware storage controller, if the selected band is initialized to the second format, and if the selected band is not initialized to the second format, initializing the selected band to the second format; and updating a data structure to indicate the selected band is initialized to the second format.

10 . The method of claim 9 , wherein the first format comprises one of unformatted, no Protection Information (PI), and a type of Protection Information (PI), and the second format comprises a different format than the first format.

11 . The method of claim 9 , wherein the data structure comprises a bitmap of the bands in the storage volume, wherein the storage volume comprises a plurality of bands, wherein the data structure indicates that the plurality of bands are formatted to the first format prior to initializing the storage volume.

12 . The method of claim 9 , further comprising:
selecting a band by choosing a band in the first format having one of a lowest and highest starting Logical Block Address.

13 . The method of claim 9 , further comprising:
determining if the selected band is initialized to the second format by observing that an identifier in the data structure corresponding to the selected band reflects the second format.

14 . The method of claim 9 , further comprising:
initializing the selected band by writing all sectors of the selected band with predetermined data reflecting the second format.

15 . A system comprising:
a storage volume comprising a plurality of bands; and a storage controller coupled to the storage volume and operable to issue a format command to the storage volume to change the format from a first format to a second format, select a band of the plurality of bands to initialize, determine if the selected band is initialized to the second format, and in response to the storage controller determining the selected band is not initialized to the second format, the storage controller initializing the selected band to the second format, and updating a data structure to indicate the selected band is initialized to the second format.

16 . The system of claim 15 , wherein the first format comprises one of unformatted, no Protection Information (PI), and a type of Protection Information (PI), and the second format comprises a different format than the first format.

17 . The system of claim 15 , wherein if there is a first write request to the selected band, the storage controller:
determines whether the selected band is either currently initialized to the first format and an initialization to the second format has not been started, currently being initialized to the second format, or previously initialized to the second format.

Assignees

• Seagate Technology Llc

Inventors

• Colline Phillip Raymond
• Wicklund Thomas George

Classifications

• G06F3/0608

  Saving storage space on storage systems · CPC title

• G06F3/0664

  at device level, e.g. emulation of a storage device or system · CPC title

• G06F3/0689 Primary

  Disk arrays, e.g. RAID, JBOD · CPC title

• G06F3/0661

  Format or protocol conversion arrangements · CPC title