Apparatus and method for managing storage of data blocks
View Patent ↗A data block storage management capability is presented. A cloud file system management capability manages storage of data blocks of a file system across multiple cloud storage services (e.g., including determining, for each data block to be stored, a storage location and a storage duration for the data block). A cloud file system management capability manages movement of data blocks of a file system between storage volumes of cloud storage services. A cloud file system management capability provides a probabilistic eviction scheme for evicting data blocks from storage volumes of cloud storage services in advance of storage deadlines by which the data blocks are to be removed from the storage volumes. A cloud file system management capability enables dynamic adaptation of the storage volume sizes of the storage volumes of the cloud storage services.
1. An apparatus, comprising:
a processor configured to:
determine a storage duration for storage of a data block in a memory, the storage duration configured to indicate a time at which the data block is scheduled to be removed from the memory;
compute a data block eviction time for the data block based on a probability density function configured to describe a probability of removing the data block from the memory at a time, within a range of time from an initial time to the time at which the data block is scheduled to be removed from the memory, since a last access time of the data block; and
evict the data block from the memory when the data block eviction time elapses without a subsequent access to the data block.
2. The apparatus of claim 1 , wherein the processor is configured to:
compute the data block eviction time when the data block is stored in the memory or accessed from the memory.
3. The apparatus of claim 1 , wherein the processor is configured to compute the probability density function as:
p
(
t
)
=
1
T
(
e
-
1
)
ⅇ
t
/
T
,
wherein T is the storage duration for the data block and t is the time since the last access time of the data block.
4. The apparatus of claim 1 , wherein, to compute the data block eviction time, the processor is configured to:
generate a uniformly distributed random variable U in the range [0:1]; and
compute the data block eviction time from a current time as T log [(e−1)U+1], wherein T is the storage duration for the data block.
5. The apparatus of claim 1 , wherein the processor is configured to determine the storage duration for the data block by computing the storage duration for the data block using cost information associated with each of a plurality of memories available for storing the data block.
6. The apparatus of claim 1 , wherein the memory is configured to host a storage volume of a cloud storage service.
7. The apparatus of claim 1 , wherein the memory is a memory of an end user computer.
8. A method, comprising:
determining, by a processor, a storage duration for storage of a data block in a memory, the storage duration configured to indicate a time at which the data block is scheduled to be removed from the memory;
computing a data block eviction time for the data block based on a probability density function configured to describe a probability of removing the data block from the memory at a time, within a range of time from an initial time to the time at which the data block is scheduled to be removed from the memory, since a last access time of the data block; and
evicting the data block from the memory when the data block eviction time elapses without a subsequent access to the data block.
9. The method of claim 8 , wherein the data block eviction time is computed when the data block is stored in the memory or accessed from the memory.
10. The method of claim 8 , further comprising:
computing the probability density function as:
p
(
t
)
=
1
T
(
e
-
1
)
ⅇ
t
/
T
,
wherein T is the storage duration for the data block and t is the time since the last access time of the data block.
11. The method of claim 8 , wherein computing the data block eviction time comprises:
generating a uniformly distributed random variable U in the range [0:1]; and
computing the data block eviction time from a current time as T log [(e−1)U+1], wherein T is the storage duration for the data block.
12. The method of claim 8 , wherein determining the storage duration for the data block comprises:
computing the storage duration for the data block using cost information associated with each of a plurality of memories available for storing the data block.
13. The method of claim 8 , wherein the memory is configured to host a storage volume of a cloud storage service.
14. The method of claim 8 , wherein the memory is a memory of an end user computer.
15. A non-transitory computer-readable storage medium storing instructions which, when executed by a computer, cause the computer to perform a method, the method comprising:
determining a storage duration for storage of a data block in a memory, the storage duration configured to indicate a time at which the data block is scheduled to be removed from the memory;
computing a data block eviction time for the data block based on a probability density function configured to describe a probability of removing the data block from the memory at a time, within a range of time from an initial time to the time at which the data block is scheduled to be removed from the memory, since a last access time of the data block; and
evicting the data block from the memory when the data block eviction time elapses without a subsequent access to the data block.
16. The non-transitory computer-readable storage medium of claim 15 , wherein the data block eviction time is computed when the data block is stored in the memory or accessed from the memory.
17. The non-transitory computer-readable storage medium of claim 15 , the method further comprising:
computing the probability density function as:
p
(
t
)
=
1
T
(
e
-
1
)
ⅇ
t
/
T
,
wherein T is the storage duration for the data block and t is the time since the last access time of the data block.
18. The non-transitory computer-readable storage medium of claim 15 , wherein computing the data block eviction time comprises:
generating a uniformly distributed random variable U in the range [0:1]; and
computing the data block eviction time from a current time as T log [(e−1)U+1], wherein T is the storage duration for the data block.
19. The non-transitory computer-readable storage medium of claim 15 , wherein determining the storage duration for the data block comprises:
computing the storage duration for the data block using cost information associated with each of a plurality of memories available for storing the data block.
20. The non-transitory computer-readable storage medium of claim 15 , wherein the memory is configured to host a storage volume of a cloud storage service.
21. The non-transitory computer-readable storage medium of claim 15 , wherein the memory is a memory of an end user computer.