RESOURCE EFFICIENT SCALE-OUT FILE SYSTEMS

• US 20120254257A1
• Filed: 03/31/2011
• Published: 10/04/2012
• Est. Priority Date: 03/31/2011
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Mitra, Soumyadeb, Hsu, Windsor W.
• Granted Patent: US 9,916,258 B2
• Time in Patent Office: Days
• US Class Current: 707/803
• CPC Class Codes: G06F 12/0846 Cache with multiple tag or data arrays being simultaneously accessible
• CPC Class Codes: G06F 12/12 Replacement control
• CPC Class Codes: G06F 16/17 Details of further file system functions
• CPC Class Codes: G06F 9/5016 the resource being the memory
• CPC Class Codes: G06F 9/5022 Mechanisms to release resources

Abstract

According to one embodiment, a file system (FS) of a storage system is partitioned into a plurality of FS partitions, where each FS partition stores segments of data files. In response to an input and output (IO) request for accessing a first of the FS partitions, a second of the FS partitions is selected that is currently in a ready state for access. The second FS partition is then removed from the ready state for access. The first FS partition is brought into a ready state for access.

Claims

1. A computer-implemented method for providing a file system, the method comprising:

partitioning a file system (FS) of a storage system into a plurality of FS partitions, each FS partition storing segments of data files;

in response to an input and output (IO) request for accessing a first of the FS partitions,

selecting a second of the FS partitions that is currently in a ready state for access;

removing the second FS partition from the ready state for access; and

bringing the first FS partition into a ready state for access.

2. The method of claim 1, wherein removing the second FS partition from the ready state for access includes unloading metadata associated with the second FS partition from a system memory of the storage system, the system memory being shared amongst the FS partitions, and wherein bringing the first FS partition into the ready state for access includes loading metadata associated with the first FS partition into the system memory.

3. The method of claim 1, wherein removing the second FS partition from the ready state for access includes powering down a storage device associated with the second FS partition, and wherein bringing the first FS partition into the ready state for access includes powering up a storage device associated with the first FS partition.

4. The method of claim 1, wherein the segments of data files stored in each FS partition are deduplicated within the FS partition.

5. The method of claim 1, further comprising:

in response to the IO request, determining whether the first FS partition is in a ready state for access; and

enqueuing the request in a pending IO queue of the file system if the first FS partition is not in the ready state for access.

6. The method of claim 5, wherein if the first FS partition is in the ready state for access, the method further comprises:

scheduling an execution of the IO request; and

incrementing a pending IO count associated with the first FS partition, wherein the pending IO count indicates a number of IO requests currently pending for execution in the first FS partition.

7. The method of claim 6, further comprising decrementing the pending IO count in response to a signal indicating that execution of the IO request has been completed.

8. The method of claim 7, further comprising:

assigning a token having an initial value to the first FS partition when the FS partition is being loaded; and

decrementing the value of the token associated with the first FS partition in response to the signal indicating a complete execution of the IO request.

9. The method of claim 8, further comprising periodically decrementing the value of the token associated with the first FS partition.

10. The method of claim 9, further comprising removing the first FS partition from the ready state for access if at least one of the pending IO count and the value of the token reaches a predetermined value.

11. The method of claim 1, wherein the second FS partition is removed from the ready state for access only if there is no IO request pending for the second FS partition and the second FS partition has been in the ready state for access for a predetermined period of time.

12. A computer-readable storage medium having instructions stored therein, which when executed by a computer, cause the computer to perform a method for managing resources of a file system, the method comprising:

partitioning a file system (FS) of a storage system into a plurality of FS partitions, each FS partition storing segments of data files;

in response to an input and output (IO) request for accessing a first of the FS partitions,

selecting a second of the FS partitions that is currently in a ready state for access;

removing the second FS partition from the ready state for access; and

bringing the first FS partition into a ready state for access.

13. The computer-readable storage medium of claim 12, wherein removing the second FS partition from the ready state for access includes unloading metadata associated with the second FS partition from a system memory of the storage system, the system memory being shared amongst the FS partitions, and wherein bringing the first FS partition into the ready state for access includes loading metadata associated with the first FS partition into the system memory.

14. The computer-readable storage medium of claim 12, wherein removing the second FS partition from the ready state for access includes powering down a storage device associated with the second FS partition, and wherein bringing the first FS partition into the ready state for access includes powering up a storage device associated with the first FS partition.

15. The computer-readable storage medium of claim 12, wherein the segments of data files stored in each FS partition are deduplicated within the FS partition.

16. The computer-readable storage medium of claim 15, wherein the method further comprises:

in response to the IO request, determining whether the first FS partition is in a ready state for access; and

enqueuing the request in a pending IO queue of the file system if the first FS partition is not in the ready state for access.

17. The computer-readable storage medium of claim 16, wherein if the first FS partition is in the ready state for access, the method further comprises:

scheduling an execution of the IO request; and

incrementing a pending IO count associated with the first FS partition, wherein the pending IO count indicates a number of IO requests currently pending for execution in the first FS partition.

18. The computer-readable storage medium of claim 17, wherein the method further comprises decrementing the pending IO count in response to a signal indicating that execution of the IO request has been completed.

19. The computer-readable storage medium of claim 17, wherein the method further comprises:

assigning a token having an initial value to the first FS partition when the FS partition is being loaded; and

decrementing the value of the token associated with the first FS partition in response to the signal indicating a complete execution of the IO request.

20. The computer-readable storage medium of claim 18, wherein the method further comprises periodically decrementing the value of the token associated with the first FS partition.

21. The computer-readable storage medium of claim 20, wherein the method further comprises removing the first FS partition from the ready state for access if at least one of the pending IO count and the value of the token reaches a predetermined value.

22. The computer-readable storage medium of claim 12, wherein the second FS partition is removed from the ready state for access only if there is no IO request pending for the second FS partition and the second FS partition has been in the ready state for access for a predetermined period of time.

23. A storage system, comprising:

a system memory;

a file system (FS) executed in the system memory, the file system having a plurality of FS partitions, each FS partition storing segments of data files;

a partition manager coupled to the file system and the system memory, wherein the partition manager is configured to

in response to an input and output (IO) request for accessing a first of the FS partitions, select a second of the FS partitions that is currently in a ready state for access,

remove the second FS partition from the ready state for access, and

bring the first FS partition into a ready state for access.