METHOD AND SYSTEM FOR TRANSFORMATION OF LOGICAL DATA OBJECTS FOR STORAGE

• US 20120117341A1
• Filed: 07/27/2010
• Published: 05/10/2012
• Est. Priority Date: 07/27/2009
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: Storwize Limited
• Inventors: AMIT, Jonathan, KOIFMAN, Chaim, MARENKOV, Sergey
• Granted Patent: US 9,218,349 B2
• Time in Patent Office: Days
• US Class Current: 711/159
• CPC Class Codes: G06F 16/116 Details of conversion of file system types or formats
• CPC Class Codes: G06F 3/0661 Format or protocol conversion arrangements
• CPC Class Codes: G06F 9/30025 Format conversion instructions, e.g. Floating-Point to Integer, decimal conversion

Abstract

There are provided a method of transforming a non-transformed stored logical data object (LO) device into a transformed LO and system thereof. The method comprises: a) in response to a respective transformation request, logically dividing the non-transformed LO in a first segment and one or more non-transformed subsequent segments, the segments having predefined size; b) generating a header for the respective transformed LO; c) processing said first segment; d) overwriting said first segment by said generated header and said transformed first segment; e) indexing said first transformed segment and said one or more non-transformed subsequent segments as constituting a part of said transformed LO; f) generating at least one index section; and g) updating the indication in the header to point that the non-transformed LO has been transformed in the transformed LO comprising said generated header, said first transformed segment, said one or more subsequent segments comprising data in non-transformed form and said at least one index section.

Claims

1. A method of transforming a non-transformed logical data object (LO) stored in a storage device into a transformed LO stored in the storage device, the storage device operable with at least one storage protocol, said method comprising:

a) in response to a respective transformation request, logically dividing the non-transformed LO into a first segment and one or more non-transformed subsequent segments, the segments having a predefined size;

b) generating a header for the respective transformed LO, said header comprising an indication that the transformation process is “

in progress”

;

c) processing said first segment to generate a transformed first segment comprising data in a transformed form;

d) if a total size of said generated header and said transformed first segment matches a predefined size criteria, overwriting said first segment with said generated header and said transformed first segment;

e) indexing said first transformed segment and said one or more non-transformed subsequent segments as constituting a portion of said transformed LO to generate indexed segments;

f) generating at least one index section comprising at least one entry holding at least information related to said indexed segments, said information comprising an offset of each segment in said non-transformed LO, indication of a storage location of each respective indexed segment, and an indication if said indexed segment comprises data in original or transformed form; and

g) updating the indication in the header to indicate that the non-transformed LO has been transformed in the transformed LO comprising said generated header, said first transformed segment, said one or more subsequent segments comprising data in non-transformed form, and said at least one index section.

2. The method of claim 1, wherein a size of the first segment is equal to the sum of a predefined size of the header and the maximum size of data in a single I/O operation in accordance with said at least one storage protocol.

3. The method of claim 1, wherein a size of each non-transformed subsequent segment is configured as equal to the maximal size of data in a single I/O operation in accordance with said at least one storage protocol.

4. The method of claim 1, wherein the predefined size criteria is characterized, at least, by a sum of predefined size of the header and a predefined maximum size of the transformed first segment.

5. The method of claim 1, wherein the transformation request is obtained by intercepting an access request to the non-transformed LO, and generating a request for transforming the non-transformed LO if said non-transformed LO matches a predefined transformation criteria.

6. The method of claim 5, wherein the predefined transformation criteria is selected from a group comprising criteria related to characteristics of the logical data object, a predefined time schedule, one or more predefined events, and combinations thereof.

7. The method of claim 1, wherein the transformation request is received from a maintenance unit configured to recognize a non-transformed LO among the stored LOs and to generate a request for transforming said recognized non-transformed LO.

8. The method of claim 1, wherein said first transformed segment and one or more subsequent non-transformed segments are indexed as data chunks sequentially stored into one or more storage blocks comprising a predefined size, wherein a storage sequence corresponds to a sequence of the segments in the non-transformed LO.

9. The method of claim 1, further comprising:

a) responsive to a request for further transformation, recognizing, via the index section, at least one subsequent non-transformed segment comprising a range comprising live data and matching predefined further transformation criteria;

b) processing the range and sequentially storing a resulting data chunk with transformed data as a new log in an allocated storage block with a predefined size; and

c) updating the index section in a manner facilitating a one-to-one relationship between each point in the data range in the non-transformed LO and the live data to be read from the transformed LO.

10. The method of claim 9, wherein the request for further transformation is obtained by intercepting a write request to the non-transformed LO, analyzing whether each respective transformed LO comprises data in original form, and, if each respective transformed LO comprises data in original form, generating a request for transforming data stored in said transformed LO in original form.

11. The method of claim 9, wherein the request for further transformation is received from a maintenance unit configured to scan the transformed LOs stored at the storage device, recognize LOs comprising data in original form, and, in accordance with predefined further transformation criteria, generate requests for transforming such data.

12. The method of claim 9, wherein the predefined further transformation criteria is selected from a group comprising criteria related to characteristics of the logical data object, a predefined time schedule, one or more predefined events, and combinations thereof.

13. The method of claim 9, further comprising writing a data range to the transformed LO, the writing further comprising:

a) in response to a respective write request, processing one or more sequentially obtained chunks of data corresponding to said data range, wherein at least one of the processed data chunks comprises data in transformed form resulting from said processing;

b) sequentially storing the processed data chunks in an allocated storage block with a predefined size, wherein storing is provided in accordance with an order of receiving the data chunks; and

c) updating the index section in a manner facilitating a one-to-one relationship between the data in the range and respective data to be read from the transformed LO.

14. The method of claim 13, wherein a response to a write request has a priority higher than a response to the request for further transformation.

15. The method of claim 1, further comprising writing a data range to the transformed LO, said writing comprising:

a) in response to a respective write request, processing one or more sequentially obtained chunks of data corresponding to said data range, wherein at least one of the processed data chunks comprises data in transformed form resulting from said processing;

b) sequentially storing the processed data chunks in an allocated storage block with a predefined size, wherein storing is provided in accordance with an order of receiving the data chunks; and

c) updating the index section in a manner facilitating a one-to-one relationship between the data in the range and respective data to be read from the transformed LO.

16. The method of claim 1 further comprising reading a data range from a transformed LO, said reading comprising:

a) in response to a respective read request, discovering all created and/or last-updated entries in the index section related to the data within the range;

b) extracting the data to be read in accordance with the mapping provided by the last-updated entries as follows;

i) for data to be read stored in the first segment, de-transforming the segment and extracting any required data;

ii) for data to be read stored in one or more subsequent non-transformed segments, reading the respective segments and extracting any required data;

iii) for otherwise stored data to be read, de-transforming the respective one or more storage blocks and extracting any required data; and

c) arranging the extracted data in accordance with their order in the range.

17. A communication device operable in a storage network and being configured to perform the method of claim 1.

18. A storage device operable in a storage network and being configured to perform the method of claim 1.

19. The storage device of claim 18, wherein the header constitutes a portion of the file system.

20. A system capable of transforming a non-transformed LO stored in a storage device into a transformed LO stored in the storage device, said storage device operatively coupled to the system in a serial manner, said system acting as a transparent bridge with respect to the stored data and being configured to perform the method of claim 1.

29. A computer program comprising computer program code means for performing the method of claim 1 when said program is operating on a computing device.

21. A system capable of transforming a non-transformed stored logical data object (LO) into a transformed LO, said system comprising:

a) means for logically dividing the non-transformed LO into a first segment and one or more non-transformed subsequent segments, the segments comprising a predefined size;

b) means for generating a header for the respective transformed LO, said header comprising an indication that the transformation process is “

in progress”

;

c) means for processing said first segment to generate a transformed first segment comprising data in transformed form;

d) means for enabling overwriting said first segment by said generated header and said transformed first segment if a total size of said generated header and said transformed first segment matches a predefined size criteria,

e) means for indexing said first transformed segment and said one or more non-transformed subsequent segments as constituting a portion of said transformed LO to generate indexed segments;

f) means for generating at least one index section comprising at least one entry holding at least information related to said indexed segments, said information comprising an offset of each segment in said non-transformed LO, an indication of a storage location of each respective indexed segment, and an indication whether said indexed segment comprises data in original or transformed form; and

g) means for updating the indication in the header to indicate that the non-transformed LO has been transformed in the transformed LO comprising said generated header, said first transformed segment, said one or more subsequent segments comprising data in non-transformed form, and said at least one index section.

22. The system of claim 21, further comprising means for intercepting an access request to the non-transformed LO, and generating a request for transforming the non-transformed LO if said non-transformed LO matches a predefined transformation criteria.

23. The system of claim 21, further comprising a maintenance unit configured to recognize a non-transformed LO among stored LOs and to generate a request for transforming said recognized non-transformed LO.

24. The system of claim 21, further comprising:

a) means for recognizing, via the index section, at least one subsequent non-transformed segment comprising a range comprising live data and matching a predefined further transformation criteria;

b) means for processing the respective range and sequentially storing the resulting data chunk with transformed data as a new log in an allocated storage block with a predefined size; and

c) means for updating the index section in a manner facilitating a one-to-one relationship between each point in the data range in the non-transformed LO and the live data to be read from the transformed LO.

25. The system of claim 24, further comprising means for intercepting a write request to the non-transformed LO, analyzing whether each respective transformed LO comprises data in original form, and, if comprising data in original form, generating a request for transforming data stored in said transformed LO in original form.

26. The system of claim 24, further comprising a maintenance unit configured to scan the transformed LOs stored at the storage device, recognize LOs comprising data in original form, and, in accordance with a predefined further transformation criteria, generate requests for transforming such data.

27. A maintenance unit configured to work in conjunction with a system capable of transforming a non-transformed stored logical data object (LO) into a transformed LO, the maintenance unit further configured to recognize a non-transformed LO among stored LOs and to generate one or more requests to the system for transforming said recognized non-transformed LO.

28. The maintenance unit of claim 27, further configured to scan the stored transformed LOs, to recognize LOs comprising data in original form, and, in accordance with predefined further transformation criteria, to generate one or more requests to the system for transforming such data.

30. A computer program as claimed in claim 27 embodied on a physical computer-readable storage medium.