System and method for providing space availability notification in a distributed striped volume set

• US 8,095,730 B1
• Filed: 07/20/2010
• Issued: 01/10/2012
• Est. Priority Date: 06/01/2007
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Jernigan, Richard P. IV, Hamilton, Eric, Jiang, Tianyu
• Primary Examiner(s): Bragdon, Reginald G
• Assistant Examiner(s): Talukdar, Arvind
• Application Number:
  US12/839,530
• Time in Patent Office: 539 Days
• Field of Search: None
• US Class Current: 711/114
• CPC Class Codes: G06F 3/0617 in relation to availability
• CPC Class Codes: G06F 3/0644 Management of space entities, e.g. partitions, extents, pools
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

A computer data storage system is described. A processor maintains a striped volume set by striping a data container over a plurality of storage nodes. A storage node determines whether space available on that node is below a predetermined threshold, the predetermined threshold indicating a low-in-space state. The storage node sends a message indicating that the storage node is in a low-in-space state. The processor accepts no further write messages to the data container as long as the storage node is in a low-in-space state.

Claims

1. A method for operating a computer data storage system, comprising:

maintaining a striped volume set by striping a data container over a plurality of storage nodes of the storage system;

determining by a first storage node of the plurality of storage nodes whether space available on the first storage node is below a predetermined threshold, the predetermined threshold indicating a low-in-space state;

sending a first message to a master data server of the storage system from the first storage node indicating that the first storage node is in a low-in-space state; and

sending a second message from said master data server to the plurality of nodes to set a low-in-space state identifier so that no further write operations are accepted for the striped volume set by the plurality of storage nodes.

2. The method as in claim 1, further comprising:

determining if a write data in a write request will fit into a selected stripe of the striped volume set, and if the write data requires more space than is available in the selected stripe, then obtaining a lock on space in a next stripe of the striped volume set to hold any data remaining after writing the data to the selected stripe, and writing the remaining data to the next stripe.

3. The method as in claim 2, further comprising:

if the write data is too much data to fit into the next stripe, then writing a further remaining data of the write data into a further next stripe.

4. The method as in claim 1, further comprising:

after detecting that a write request will place a storage node into a low-in-space state, writing a data of the write request into a reserved space of a storage node of the plurality of storage nodes.

5. The method as in claim 1, further comprising:

configuring the master data server to periodically send a space availability detection message to each storage node of the plurality of storage nodes.

6. The method as in claim 5, further comprising:

in response to receiving the space availability detection message, a storage node determining whether space available on that node is below a predetermined threshold, the predetermined threshold indicating a low-in-space state.

7. The method as in claim 6, further comprising:

returning a response from each storage node indicating whether the each storage node is in a low-in-space state.

8. The method as in claim 7, further comprising:

in response to said master data server receiving a response message from a responding node of the plurality of nodes indicating that the responding node is in a low-in-space state, setting a status of the plurality of nodes to indicate that the plurality of nodes is in a low-in-space state.

9. The method as in claim 8, further comprising:

sending, in response to the message from the responding node, a third message from said master data server to all nodes of the plurality of nodes to set a low-in-space state identifier.

10. The method as in claim 9, further comprising:

accepting no further write operations in the data container while one or more of the storage node is in a low-in space state.

11. The method as in claim 10, further comprising:

accepting write operations for the data container after each storage node of the plurality of storage nodes has transitioned to a state indicating that it is not in a low-in space state.

12. A computer data storage system apparatus, comprising:

a processor to maintain a striped volume set by striping a data container over a plurality of storage nodes of the storage system;

a first storage node of the plurality of storage nodes to determine whether space available on the first storage node is below a predetermined threshold, the predetermined threshold indicating a low-in-space state;

the first storage node to send a message to a master data server of the storage system indicating that the first storage node is in a low-in-space state; and

sending a second message by the master data server to the plurality of nodes to set a low-in-space state identifier so that no further write operations are accepted for the striped volume set by the plurality of storage nodes.

13. The apparatus as in claim 12, further comprising:

the processor to determine if a write data in a write request will fit into a selected stripe of the striped volume set, and if the write data requires more space than is available in the selected stripe, then obtaining a lock on space in a next stripe of the striped volume set to hold any data remaining after writing the data to the selected stripe, and writing the remaining data to the next stripe.

14. The apparatus as in claim 13, further comprising:

if the write data is too much data to fit into the next stripe, then writing a further remaining data of the write data into a further next stripe.

15. The apparatus as in claim 12, further comprising:

the processor, after detecting that a write request will place a storage node into a low-in-space state, to write a data of the write request into a reserved space of a storage node of the plurality of storage nodes.

16. The apparatus as in claim 12, further comprising:

a master data server to periodically send a space availability detection message to each storage node of the plurality of storage nodes.

17. The apparatus as in claim 12, further comprising:

in response to receiving the space availability detection message, a storage node to determine whether space available on that node is below a predetermined threshold, the predetermined threshold indicating a low-in-space state.

18. The apparatus as in claim 17, further comprising:

each storage node to return a third message to the master data server indicating whether the each storage node is in a low-in-space state.

19. The apparatus as in claim 18, further comprising:

the master data server, in response to receiving the third message, to set a status of the plurality of nodes to indicate that the plurality of nodes is in a low-in-space state.

20. The apparatus as in claim 18, further comprising:

said master data server, in response to the third message, sending a message to all nodes of the plurality of nodes to set a low-in-space state identifier.

21. The apparatus as in claim 20, further comprising:

the processor to accept no further write operations in the data container while one or more of the storage nodes of the plurality of nodes is in a low-in space state.

22. The apparatus as in claim 21, further comprising:

the processor to accept write operations for the data container after each storage node of the plurality of storage nodes has transitioned to a state indicating that it is not in a low-in-space state.

23. A computer readable nontransitory storage media, comprising:

said computer readable storage media containing program instructions for execution on a processor for a method of operating a computer data storage system, the program instructions for,

maintaining a striped volume set by striping a data container over a plurality of storage nodes of the storage system;

determining by a first storage node of the plurality of storage nodes whether space available on the first storage node is below a predetermined threshold, the predetermined threshold indicating a low-in-space state;

sending a first message from a storage node to a master data server of the storage system indicating that the storage node is in a low-in-space state; and

sending a second message from said master data server to the plurality of nodes to is set a low-in-space state identifier so that no further write operations are accepted for the striped volume set by the plurality of storage nodes.