Fragment filling for storage system with in-line compression
Methods and apparatus are provided for reporting fragment filling in storage systems. An exemplary method comprises obtaining at least one compressed allocation unit of data in a storage system; reserving space for the at least one compressed allocation unit in a compressed segment based on a greater of (i) a size of the at least one compressed allocation unit, and (ii) a minimum target fragment length specified for at least one write operation class; and writing the at least one compressed allocation unit to the reserved space. An attempt is optionally first made to fill the at least one compressed allocation unit of data in a free extent and/or a hidden fragment of at least one compressed segment prior to reserving the space. The reserving the space is optionally only performed if the attempt to fill the at least one compressed allocation unit of data is not successful.
1. A method, comprising:
obtaining a plurality of minimum target fragment lengths, each minimum target fragment length specified for a respective one of a plurality of classes of write operations;
compressing one or more allocation units of data associated with a write operation to obtain at least one compressed allocation unit of data in a storage system, wherein the write operation corresponds to one of the classes of write operations;
determining that at least one existing allocation unit of at least one compressed segment of said storage system cannot be filled with said at least one compressed allocation unit of data, wherein said at least one existing allocation unit comprises at least one of a free fragment and a hidden fragment; and
in response to said determining:
reserving space for said at least one compressed allocation unit in a compressed segment of said storage system, wherein a size of said reserved space is a greater of (i) a size of said at least one compressed allocation unit, and (ii) the minimum target fragment length specified for the write operation class corresponding to said write operation, wherein the plurality of minimum target fragment lengths comprises a first minimum target fragment length specified for a class of full write operations and a second minimum target fragment length specified for a class of partial write operations, wherein said first minimum target fragment length is different than said second minimum target fragment length; and
writing said at least one compressed allocation unit of data to at least a portion of said reserved space in the compressed segment.
2. The method of claim 1 , wherein a third minimum target fragment length is specified for a class of allocated write operations.
3. The method of claim 2 , wherein the third minimum target fragment length is different from both the first minimum target fragment length and the second minimum target fragment length.
4. The method of claim 1 , wherein the step of compressing one or more allocation units associated with said write operation is selectively performed based on one or more heuristics.
5. The method of claim 1 , wherein the step of reserving space is only performed if it is determined that the at least one existing allocation unit of at least one compressed segment of said storage system cannot be filled.
6. The method of claim 1 , wherein the storage system is enabled with inline compression.
7. The method of claim 1 , wherein the compressed segment comprises a set of contiguous allocation units having at least two different sizes.
8. The method of claim 1 , wherein each of the first minimum target fragment length and the second minimum target fragment length have a fixed size.
9. A computer program product, comprising a non-transitory machine-readable storage medium having encoded therein executable code of one or more software programs, wherein the one or more software programs when executed by at least one processing device perform the following steps:
obtaining a plurality of minimum target fragment lengths, each minimum target fragment length specified for a respective one of a plurality of classes of write operations;
compressing one or more allocation units of data associated with a write operation to obtain at least one compressed allocation unit of data in a storage system, wherein the write operation corresponds to one of the classes of write operations;
determining that at least one existing allocation unit of at least one compressed segment of said storage system cannot be filled with said at least one compressed allocation unit of data, wherein said at least one existing allocation unit comprises at least one of a free fragment and a hidden fragment; and
in response to said determining:
reserving space for said at least one compressed allocation unit in a compressed segment of said storage system, wherein a size of said reserved space is a greater of (i) a size of said at least one compressed allocation unit, and (ii) the minimum target fragment length specified for the write operation class corresponding to said write operation, wherein the plurality of minimum target fragment lengths comprises a first minimum target fragment length specified for a class of full write operations and a second minimum target fragment length specified for a class of partial write operations, wherein said first minimum target fragment length is different than said second minimum target fragment length; and
writing said at least one compressed allocation unit of data to at least a portion of said reserved space in the compressed segment.
10. The computer program product of claim 9 , wherein the step of compressing one or more allocation units associated with said write operation is selectively performed based on one or more heuristics.
11. The computer program product of claim 9 , wherein the step of reserving space is only performed if it is determined that the at least one existing allocation unit of at least one compressed segment of said storage system cannot be filled.
12. The computer program product of claim 9 , wherein the storage system is enabled with inline compression.
13. The computer program product of claim 9 , wherein a third minimum target fragment length is specified for a class of allocated write operations.
14. The computer program product of claim 9 , wherein the compressed segment comprises a set of contiguous allocation units having at least two different sizes.
15. A system, comprising:
a memory; and
at least one processing device, coupled to the memory, operative to implement the following steps:
obtaining a plurality of minimum target fragment lengths, each minimum target fragment length specified for a respective one of a plurality of classes of write operations;
compressing one or more allocation units of data associated with a write operation to obtain at least one compressed allocation unit of data in a storage system, wherein the write operation corresponds to one of the classes of write operations;
determining that at least one existing allocation unit of at least one compressed segment of said storage system cannot be filled with said at least one compressed allocation unit of data, wherein said at least one existing allocation unit comprises at least one of a free fragment and a hidden fragment; and
in response to said determining:
reserving space for said at least one compressed allocation unit in a compressed segment of said storage system, wherein a size of said reserved space is a greater of (i) a size of said at least one compressed allocation unit, and (ii) the minimum target fragment length specified for the write operation class corresponding to said write operation, wherein the plurality of minimum target fragment lengths comprises a first minimum target fragment length specified for a class of full write operations and a second minimum target fragment length specified for a class of partial write operations, wherein said first minimum target fragment length is different than said second minimum target fragment length; and
writing said at least one compressed allocation unit of data to at least a portion of said reserved space in the compressed segment.
16. The system of claim 15 , wherein a third minimum target fragment length is specified for a class of operations.
17. The system of claim 16 , wherein the third minimum target fragment length is different from both the first minimum target fragment length and the second minimum target fragment length.
18. The system of claim 15 , wherein the step of compressing one or more allocation units associated with said write operation is selectively performed based on one or more heuristics.
19. The system of claim 15 , wherein the step of reserving space is only performed if it is determined that the at least one existing allocation unit of at least one compressed segment of said storage system cannot be filled.
20. The system of claim 15 , wherein the storage system is enabled with inline compression.