Dispersed storage write process
View Patent ↗A dispersed storage (DS) method begins by issuing a plurality of write commands to a plurality of DS storage units. The method continues by receiving a write acknowledgement from one of the plurality of DS storage units to produce a received write acknowledgement. The method continues by issuing a plurality of commit commands to the plurality of DS storage units when a write threshold number of the received write acknowledgements have been received. The method continues by receiving a commit acknowledgement from a DS storage unit of the plurality of DS storage units to produce a received commit acknowledgement. The method continues by issuing a plurality of finalize commands to the plurality of DS storage units when a write threshold number of the received commit acknowledgements have been received.
1. A method for execution by a dispersed storage (DS) storage unit, the method comprises:
receiving a write command regarding a data slice;
in response to receiving the write command, storing a new version of the data slice in a non-visible manner;
maintaining an old version of the data slice in a visible manner;
transmitting a write acknowledgement in response to receiving the write command;
receiving a commit command regarding the data slice within a commit time period;
transmitting a commit acknowledgement in response to receiving the commit command; and
receiving a finalize command regarding the data slice within a finalize time period.
2. The method of claim 1 further comprises:
in response to receiving the commit command, making the new version of the data slice visible; and
making the older version of the data slice not visible.
3. The method of claim 2 further comprises:
when the finalize command is not received within the finalize time period, deleting a new version of the data slice; and
making the older version of the data slice visible.
4. The method of claim 2 further comprises:
in response to receiving the finalize command, deleting the old version of data slice.
5. The method of claim 1 further comprises:
when the commit command is not received within the commit time period, deleting a new version of the data slice.
6. The method of claim 1 further comprises:
prior to receiving the finalize command, receiving a rollback command; and
in response to the rollback command, deleting a new version of the data slice.
7. The method of claim 1 further comprises:
after receiving the finalize command, receiving an undo command; and
in response to the undo command, deleting a new version of the data slice; and
making the older version of the data slice visible.
8. A dispersed storage (DS) storage unit comprises:
an interface module;
memory; and
a processing module operable to:
receive, via the interface module, a write command regarding a data slice;
in response to receiving the write command, facilitate storing a new version of the data slice in the memory in a non-visible manner; and
facilitate maintaining an old version of the data slice visible in the memory;
transmit, via the interface module, a write acknowledgement in response to receiving the write command;
receive, via the interface module, a commit command regarding the data slice within a commit time period;
transmit, via the interface module, a commit acknowledgement in response to receiving the commit command; and
receive, via the interface module, a finalize command regarding the data slice within a finalize time period.
9. The apparatus of claim 8 wherein the processing module is further operable to:
in response to commit command, facilitate making the new version of the data slice visible in the memory; and
facilitate making the old version of the data slice not visible in the memory.
10. The apparatus of claim 9 wherein the processing module is further operable to:
when the finalize command is not received within the finalize time period, facilitate deleting a new version of the data slice from the memory; and
facilitate making the older version of the data slice visible in the memory.
11. The apparatus of claim 9 wherein the processing module is further operable to:
in response to receiving the finalize command, facilitate deleting the old version of data slice from the memory.
12. The apparatus of claim 8 wherein the processing module is further operable to:
when the commit command is not received within the commit time period, facilitate deleting a new version of the data slice from the memory.
13. The apparatus of claim 8 wherein the processing module is further operable to:
prior to receiving the finalize command, receive a rollback command; and
in response to the rollback command, facilitate deleting a new version of the data slice from the memory.
14. The apparatus of claim 8 wherein the processing module is further operable to:
after receiving the finalize command, receive an undo command; and
in response to the undo command, facilitate deleting a new version of the data slice from the memory; and
facilitate making the older version of the data slice visible in the memory.