Storage apparatus, data management method, and non-transitory computer readable medium
A server including a memory unit, a processor unit, and a storage device, wherein the memory unit has: a CM; an SM which stores management information; and a log buffer for storing log data indicating contents of change to the CM and the SM. The storage device has a log chunk for storing the log data, and the processor unit is configured to: store target data corresponding to an I/O request in the CM; generate log data of contents of change with respect to the CM and the SM, and to store the pieces of the generated log data in the log buffer; write a plurality of pieces of log data stored in the log buffer into the log chunk; and transmit, after all of the pieces of log data corresponding to the I/O request are written into the log chunk, a response of good to a request source.
1. A storage apparatus which receives an I/O request and manages target data being a target of the I/O request, the storage apparatus comprising:
a memory unit, a processor unit, and a non-volatile storage device, wherein
the memory unit has:
a cache area for temporarily storing the target data;
a management area for storing management information for managing the target data in the cache area; and
a log buffer for storing log data indicating contents of change with respect to the cache area and log data indicating contents of change with respect to the management area,
the non-volatile storage device has
a log chunk for storing the log data, and
the processor unit is configured to:
store, when receiving the I/O request, target data corresponding to the I/O request in the cache area;
generate, when the target data corresponding to the I/O request is stored in the cache area, log data of contents of change with respect to the cache area and log data of contents of change with respect to the management area, and store the pieces of the generated log data in the log buffer;
collectively write a plurality of the pieces of log data stored in the log buffer into the log chunk; and
transmit, after all of the pieces of log data corresponding to the I/O request are written into the log chunk, a response of good indicating that the I/O request was properly processed to a request source of the I/O request.
2. The storage apparatus according to claim 1 , wherein
the processor unit is configured to
transmit, when an amount of log data stored in the log buffer becomes equal to or larger than a prescribed amount of data, a plurality of the pieces of log data stored in the log buffer to the log chunk.
3. The storage apparatus according to claim 1 , wherein
the processor unit is configured to
transmit, to the log chunk, only a latest piece of log data in a plurality of pieces of log data indicating a change with respect to a same address and range in the memory unit among the plurality of the pieces of log data in the log buffer.
4. The storage apparatus according to claim 1 , wherein
the processor unit is configured to
write the log data into the log chunk when a process of writing log data previously stored in the log buffer into the log chunk is not being executed.
5. The storage apparatus according to claim 1 , wherein
the processor unit is configured to
generate, based on log data written into the log chunk, a memory image of the cache area and the management area at a time point when a change corresponding to the log data has been performed in a memory chunk of the non-volatile storage device.
6. The storage apparatus according to claim 5 , wherein
the processor unit is configured to
generate a memory image of the cache area and the management area by using only a latest piece of log data with respect to a plurality of pieces of log data indicating a change with respect to a same address and range in the memory unit among the log data written into the log chunk.
7. The storage apparatus according to claim 5 , wherein
the processor unit is configured to
update, when it is necessary to recover a state of the memory unit, the memory image generated in the memory chunk of the non-volatile storage device based on the log data written into the log chunk, and
reflect the memory image on the memory unit.
8. The storage apparatus according to claim 1 , wherein
the processor unit is configured to
transmit log data of contents of change with respect to the cache area and at least a part of log data of contents of change with respect to the management area to another storage apparatus configured to manage a copy of data managed by the storage apparatus.
9. A data management method used by a storage apparatus which receives an I/O request and manages target data being a target of the I/O request,
the storage apparatus including a memory unit, a processor unit, and a non-volatile storage device,
the memory unit having:
a cache area which temporarily stores the target data;
a management area which stores management information for managing the target data in the cache area; and
a log buffer for storing log data indicating contents of change with respect to the cache area and log data indicating contents of change with respect to the management area,
the non-volatile storage device having
a log chunk for storing the log data,
the data management method comprising the steps of:
storing, when receiving the I/O request, target data corresponding to the I/O request in the cache area;
generating, when the target data corresponding to the I/O request is stored in the cache area, log data of contents of change with respect to the cache area and log data of contents of change with respect to the management area, and storing the pieces of the generated log data in the log buffer;
collectively writing a plurality of the pieces of log data stored in the log buffer into the log chunk; and
transmitting, after all of the pieces of log data corresponding to the I/O request are written into the log chunk, a response of good indicating that the I/O request was properly processed to a request source of the I/O request.
10. A non-transitory computer readable medium storing data management program to be executed by a computer constituting a storage apparatus which receives an I/O request, and stores and manages target data being a target of the I/O request,
the computer including a memory unit, a processor unit, and a non-volatile storage device,
the memory unit having:
a cache area which temporarily stores the target data;
a management area which stores management information for managing the target data in the cache area; and
a log buffer for storing log data indicating contents of change with respect to the cache area and log data indicating contents of change with respect to the management area,
the non-volatile storage device having
a log chunk for storing the log data,
the data management program causing the computer to:
store, when receiving the I/O request, target data corresponding to the I/O request in the cache area;
generate, when the target data corresponding to the I/O request is stored in the cache area, log data of contents of change with respect to the cache area and log data of contents of change with respect to the management area, and store the pieces of the generated log data in the log buffer;
collectively write a plurality of the pieces of log data stored in the log buffer into the log chunk; and
transmit, after all of the pieces of log data corresponding to the I/O request are written into the log chunk, a response of good indicating that the I/O request was properly processed to a request source of the I/O request.