Front end intelligence for monitoring back end state
View Patent ↗Apparatus, methods, and other embodiments associated with providing front end intelligence for monitoring back end state are described. One example method includes controlling a first entity to request that a second entity perform a multi-state stateful operation (e.g., file create). The method includes receiving notice from the second entity that the stateful operation has attained a first state (e.g., partial file create complete) and, upon receiving the notice, maintaining, at the first entity, information (e.g., sequence number, metadata) associated with the stateful operation. The method also includes, upon receiving notice that the second entity lost state before the stateful operation attained a second state, selectively providing to the second entity a portion of the information maintained at the first entity, and upon receiving notice from the second entity that the stateful operation has attained the second state, terminating maintaining the information associated with the stateful operation.
1. A non-transitory computer-readable medium storing computer-executable instructions that when executed by an apparatus cause the apparatus to perform a method, the method comprising:
receiving, at a first entity, a first notice from a second entity that a multi-state stateful operation has attained a first state in the second entity, the multi-state stateful operation being a file create operation, the first state being a partial file creation completion state where metadata associated with a file is established by the second entity in a first location that is susceptible to state loss on the second entity;
upon receiving the first notice, beginning maintenance, at the first entity, of information associated with the stateful operation;
upon determining that the second entity lost state before the stateful operation attained a second state, selectively providing from the first entity to the second entity a portion of the information maintained at the first entity, the second state being a total file creation completion state where metadata associated with the file is established by the second entity in a second location that is less susceptible to state loss on the second entity than the first location; and
upon receiving, at the first entity, a second notice from the second entity that the stateful operation has attained the second state in the second entity, terminating maintenance of the information associated with the stateful operation at the first entity.
2. The non-transitory computer-readable medium of claim 1 , the method comprising:
controlling the first entity to request that the second entity perform the multi-state stateful operation.
3. The non-transitory computer-readable medium of claim 1 , the first entity being a client configured to use a shared storage device file system, the second entity being a server configured to use the shared storage device file system and to provide a service for the shared storage device file system, the server being configured to perform the stateful operation.
4. The non-transitory computer-readable medium of claim 1 , the first entity being a front end configured to use a shared storage device file system, the second entity being a back end configured to use the shared storage device file system and to provide a service for the shared storage device file system, the back end being configured to perform the stateful operation.
5. The non-transitory computer-readable medium of claim 1 , the first entity being one of, a front end configured to use a shared storage device file system, a client configured to use the shared storage device file system, and a process configured to use the shared storage device file system, the second entity being one of, a back end configured to use the shared storage device file system, a server configured to use the shared storage device file system, a server process configured to use the shared storage device file system, and a metadata controller configured to manage the shared storage device file system, and to provide a service for the shared storage device file system, the second entity being configured to perform the stateful operation.
6. The non-transitory computer-readable medium of claim 1 , where the first notice received from the second entity comprises an identifier of the stateful operation.
7. The non-transitory computer-readable medium of claim 6 , the identifier being a sequence number.
8. The non-transitory computer-readable medium of claim 6 , where the stateful operation is a file system operation and where the first notice received from the second entity includes metadata describing a file associated with the file system operation.
9. The non-transitory computer-readable medium of claim 6 , where the information associated with the stateful operation that is maintained at the first entity includes the identifier.
10. The non-transitory computer-readable medium of claim 9 , where the stateful operation is a file system operation and where the information associated with the stateful operation that is maintained at the first entity includes one or more of, metadata describing a file associated with the file system operation, and data associated with the file associated with the file system operation.
11. The non-transitory computer-readable medium of claim 1 , where determining that the second entity lost state before the stateful operation attained a second state includes receiving the identity of the last multi-state stateful operation completed by the second entity before the second entity lost state.
12. The non-transitory computer-readable medium of claim 1 , where receiving the second notice from the second entity includes receiving one or more of, the identity of the last multi-state stateful operation performed by the second entity, and an identifier of a multi-state stateful operation completed by the second entity.
13. A non-transitory computer-readable medium storing computer-executable instructions that when executed by an apparatus cause the apparatus to perform a method, the method comprising:
receiving, at a second entity, from a first entity, a request that the second entity perform a multi-state stateful operation, the multi-state stateful operation being a file create operation;
providing first notice to the first entity from the second entity that the stateful operation has attained a first state;
providing second notice to the first entity from the second entity that the stateful operation has attained a second state;
providing failure notice to the first entity from the second entity that the second entity lost state before advancing the stateful operation from the first state to the second state; and
receiving, at the second entity, from the first entity, information from which the second entity can restart the stateful operation,
where the first state is a partial file creation completion state where metadata associated with a file is established in volatile memory associated with the second entity and where the first state is susceptible to state loss on the second entity, and
where the second state is a total file creation completion state where metadata associated with the file is established in a non-volatile storage device associated with the second entity and where the second state is not susceptible to state loss on the second entity.
14. The non-transitory computer-readable medium of claim 13 ,
the first entity being one of, a front end configured to use a shared storage device file system, a client configured to use the shared storage device file system, and a process configured to use the shared storage device file system,
the second entity being one of, a back end configured to use the shared storage device file system, a server configured to use the shared storage device file system, a server process configured to use the shared storage device file system, and a metadata controller configured to manage the shared storage device file system, and to provide a service for the shared storage device file system,
the second entity being configured to perform the stateful operation.
15. An apparatus, comprising:
a processor;
a memory;
a set of logics; and
an interface configured to connect the processor, the memory, and the set of logics,
the set of logics comprising:
a request logic configured to request that a shared storage device file system server perform a multi-step file system operation on a file, where the file system operation is a file create operation, where the multi-step file system operation includes a first state and a second state,
where the first state is a partial file creation completion state where metadata associated with a file is established in a first location associated with the server that is susceptible to a problem on the server, and
where the second state is a total file creation completion state where metadata associated with the file is established in a second location associated with the server that is not susceptible to a problem on the server;
a maintenance logic configured to maintain information suitable for re-establishing state for the multi-step file system operation in the shared storage device file system server, where the information suitable for re-establishing state comprises:
file metadata; and
a sequence number employed by the shared storage device file system server to identify the file and the file system operation; and
a recovery logic configured to provide the information suitable for re-establishing state to the shared storage device file system server upon determining that the shared storage device file system server lost state before the multi-step file system operation achieved a desired state.
16. The apparatus of claim 15 , where maintaining information suitable for re-establishing state for the multi-step file system operation in the shared storage device file system server comprises one or more of, a sequence number associated with the file system operation, metadata describing a file associated with the file system operation, and data associated with the file associated with the file system operation.
17. An apparatus, comprising:
a processor;
a memory;
a set of logics; and
an interface configured to connect the processor, the memory, and the set of logics,
the set of logics comprising:
a metadata control logic configured:
to establish metadata for a file that is being created using a multi-step file creation operation,
to write the metadata to a volatile memory that is susceptible to state loss in the apparatus as part of a first state in the file creation operation,
to write the metadata to a non-volatile storage that is not susceptible to state loss in the apparatus as part of a second state in the file creation operation, and
to report the state of the file and the file creation operation to an entity that requested the file creation operation; and
a restart logic configured to report loss of state in the apparatus and to accept information suitable for restarting the file creation operation from the entity that requested the file creation operation and to which the apparatus reported the state of the file and the file creation operation,
where the multi-step stateful file system operation includes a first state and a second state,
where the first state is a partial file creation completion state, and
where the second state is a total file creation completion state,
where the information suitable for restarting the file creation operation comprises one or more of, file metadata, file data, and a sequence number employed by the apparatus to identify the file and the file create operation.