Storage device including nonvolatile memory device and method of performing backup based on zone features
A storage device, including: a nonvolatile memory device including memory cells; and a controller configured to: allocate zones to a storage space in response to a request of an external host device, select two or more erase units among erase units to be allocated to each of the zones based on a zone map table, and fixedly and sequentially manage logical addresses of data written in the zones. The controller may include an internal buffer configured to store first data to be written in a first zone, and may be further configured to perform a backup operation for the first data by selecting an erase unit in which the first data is to be written, and a cell type of the erase unit based on a feature of the first zone.
1 . A storage device comprising:
a nonvolatile memory device comprising a plurality of memory cells; and
a controller configured to perform a write operation on at least one write unit included in the plurality of memory cells, and to perform an erase operation on at least one erase unit included in the plurality of memory cells,
wherein the controller is further configured to:
allocate a plurality of zones to a storage space of the nonvolatile memory device in response to a request of an external host device,
select two or more erase units among a plurality of erase units of the plurality of memory cells to be allocated to each of the plurality of zones based on a zone map table, and
fixedly and sequentially manage logical addresses of data written in the plurality of zones,
wherein the controller comprises an internal buffer configured to store first data to be written in a first zone from among the plurality of zones,
wherein the controller is further configured to perform a backup operation for the first data by selecting an erase unit in which the first data is to be written, and a cell type of the erase unit based on a comparison between at least one target feature corresponding to the first data and at least one feature of the first zone,
wherein the internal buffer comprises zone buffers,
wherein a number of the zone buffers is less than a number of the plurality of zones, and
wherein, based on a write request for a new zone being received from the external host device while all of the zone buffers are used, the controller is further configured to:
write buffer data stored in a zone buffer among the zone buffers in the erase unit; and
allocate the zone buffer to the new zone.
2 . The storage device of claim 1 , wherein the nonvolatile memory device comprises a user area to which the plurality of zones are allocated, and a reserved area, and
wherein the controller is further configured to select the cell type of the erase unit from among cell types of erase units included in the reserved area.
3 . The storage device of claim 1 , wherein the at least one feature of the first zone comprises a cell type of the first zone, and
wherein the controller is further configured to select the erase unit based on a number of bits per memory cell of the erase unit being smaller than a number of bits per memory cell of the first zone.
4 . The storage device of claim 1 , wherein the controller is further configured to select the erase unit based on a target reliability corresponding to the internal buffer, and
wherein a number of bits written per memory cell of the erase unit decreases as the target reliability increases.
5 . The storage device of claim 1 , wherein the controller is further configured to select the erase unit based on an endurance of the nonvolatile memory device, and
wherein a number of bits written per memory cell of the erase unit decreases as the endurance decreases.
6 . The storage device of claim 1 , wherein the controller is further configured to select the erase unit based on a target performance requested by the external host device, and
wherein a number of bits written per memory cell of the erase unit decreases as the target performance increases.
7 . The storage device of claim 1 , wherein the controller is further configured to select the erase unit based on a size of the first data, and
wherein a number of bits written per memory cell of the erase unit decreases as the size increases.
8 . The storage device of claim 1 , wherein the controller is further configured to select the erase unit based on an update frequency of the first data, and
wherein a number of bits written per memory cell of the erase unit decreases as the update frequency increases.
9 . The storage device of claim 1 , wherein the controller is further configured to select the erase unit based on a factor corresponding to the backup operation.
10 . The storage device of claim 1 , wherein the backup operation is performed based on receiving at least one of a force unit access (FUA) request, a power off notification (PON), and a flush request.
11 . The storage device of claim 10 , wherein, based on the PON being received, the controller is further configured to select the erase unit based on the erase unit having a single level cell (SLC) type.
12 . The storage device of claim 10 , wherein, based on the PON being received, the controller is further configured to write buffer data corresponding to all zones stored in the internal buffer in the erase unit.
13 . The storage device of claim 12 , wherein, at a next power-on time, the controller is further configured to trigger migration of the data written in the erase unit.
14 . The storage device of claim 10 , wherein, after the first data is written in the erase unit based on receiving the FUA request or the flush request, the controller is further configured to trigger migration of the data written in the erase unit.
15 . A storage device comprising:
a nonvolatile memory device comprising a plurality of memory cells; and
a controller configured to perform a write operation on at least one write unit included in the plurality of memory cells, and to perform an erase operation on at least one erase unit included in the plurality of memory cells,
wherein the controller is further configured to:
allocate a plurality of zones to a storage space of the nonvolatile memory device in response to a request of an external host device,
select two or more erase units among a plurality of erase units of the plurality of memory cells to be allocated to each of the plurality of zones based on a zone map table, and
fixedly and sequentially manage logical addresses of data written in the plurality of zones,
wherein the controller comprises an internal buffer comprising zone buffers,
wherein the controller is further configured to perform a backup operation for buffer data stored in the internal buffer by collecting the buffer data corresponding to each zone buffer of the zone buffers to be written in an erase unit,
wherein the erase unit is selected based on a comparison between at least one target feature corresponding to the buffer data and at least one feature of a zone corresponding to the erase unit,
wherein a number of the zone buffers is less than a number of the plurality of zones, and
wherein, based on a write request for a new zone being received from the external host device while all of the zone buffers are used, the controller is further configured to:
write buffer data stored in a zone buffer among the zone buffers in the erase unit; and
allocate the zone buffer to the new zone.
16 . The storage device of claim 15 , wherein the nonvolatile memory device comprises a user area to which the plurality of zones are allocated, and a reserved area, and
wherein the controller is further configured to select a first erase unit, in which first data corresponding to a first zone are to be written, from among erase units of the reserved area.
17 . The storage device of claim 15 , wherein the controller is further configured to write the buffer data in the erase unit using a sequence of logical addresses.
18 . The storage device of claim 15 , wherein the backup operation is requested using at least one of a force unit access (FUA) request, a flush request, and a power off notification (PON).
19 . A storage device comprising:
a nonvolatile memory device comprising a plurality of memory cells; and
a controller configured to perform a write operation on at least one write unit included in the plurality of memory cells, and to perform an erase operation on at least one erase unit included in the plurality of memory cells,
wherein the controller is further configured to:
allocate a plurality of zones to a storage space of the nonvolatile memory device in response to a request of an external host device,
select two or more erase units among a plurality of erase units of the plurality of memory cells to be allocated to each of the plurality of zones based on a zone map table, and
fixedly and sequentially manage logical addresses of data written in the plurality of zones,
wherein the controller comprises an internal buffer comprising zone buffers,
wherein the controller is further configured to:
perform a first backup operation for first data corresponding to a first zone, which are stored in a zone buffer corresponding to the first zone from among the zone buffers, by selecting a cell type of a first erase unit, in which the first data are to be written, based on a comparison between at least one target feature corresponding to the first data and at least one feature of the first zone, and
perform a second backup operation for buffer data stored in the zone buffers by collecting the buffer data for each zone buffer to be written in a second first erase unit,
wherein a number of the zone buffers is less than a number of the plurality of zones, and
wherein, based on a write request for a new zone being received from the external host device while all of the zone buffers are used, the controller is further configured to:
write buffer data stored in the zone buffer among the zone buffers in the first erase unit; and
allocate the zone buffer to the new zone.