Methmod to manage nvme multi-namespace in Linux

[jackeichen]

Step 1 Check nvme information, get controller id and namespace id

# pynvme list-subsys
nvme-subsys0 - NQN=nqn.1994-11.com.samsung:nvme:PM9A3:2.5-inch:XXXXXXXXXXXXX
\
 +- nvme0 pcie 0000:02:00.0 live - cntlid=6
 \
  +- nvme0n1 - path=/dev/nvme0n1 nsid=1 wwid=eui.xxxxxxxxxxxxxxxxxxx5384500000006

Step 2 Detach the namespace, "Command success" means success to detach

# pynvme nvme-detach-ns /dev/nvme0 -n 1 -c 6
Command Success

Step 3 Delete the namespace

# pynvme nvme-delete-ns /dev/nvme0 -n 1
Command Success

Step 4 Create one or more Namespace

Typical Capacity Table

Capacity	LBA Format	Namespace Capacity
960G	512B + 0 B	1875385008
1.6T	512B + 0 B	3125627568
1.92T	512B + 0 B	3750748848
3.2T	512B + 0 B	6251233968
3.84T	512B + 0 B	7501476528
6.4T	512B + 0 B	12502446768
7.68T	512B + 0 B	15002931888

# pynvme nvme-create-ns /dev/nvme0 -s 1875385008 -c 1875385008 -f 0
Command Success

Namespace Identifier is: 1
# pynvme nvme-create-ns /dev/nvme0 -s 3125627568 -c 3125627568 -f 0
Command Success

Namespace Identifier is: 2
# pynvme list-ns /dev/nvme0 -a
[   0]:1
[   1]:2

Step 5 Attach the namespace

# pynvme nvme-attach-ns /dev/nvme0 -n 1 -c 6
Command Success

# pynvme nvme-attach-ns /dev/nvme0 -n 2 -c 6
Command Success

# pynvme list-ns /dev/nvme0
[   0]:1
[   1]:2
#
# pynvme list
Node                 SN                   Model                                    Namespace Usage                      Format           FW Rev
-------------------- -------------------- ---------------------------------------- --------- -------------------------- ---------------- --------
/dev/nvme0n1         XXXXXXXXXXXXXX       SAMSUNG MZQL23T8HCLS-00B7C               1         960.20 GB / 960.20 GB      512   B + 0  B   GDC56C2Q
/dev/nvme0n2         XXXXXXXXXXXXXX       SAMSUNG MZQL23T8HCLS-00B7C               2         1.60 TB / 1.60 TB          512   B + 0  B   GDC56C2Q
#
# pynvme list-subsys
nvme-subsys0 - NQN=nqn.1994-11.com.samsung:nvme:PM9A3:2.5-inch:XXXXXXXXXXXXX
\
 +- nvme0 pcie 0000:02:00.0 live - cntlid=6
 \
  +- nvme0n1 - path=/dev/nvme0n1 nsid=1 wwid=eui.xxxxxxxxxxxxxxxxxxx5384500000007
  +- nvme0n2 - path=/dev/nvme0n2 nsid=2 wwid=eui.xxxxxxxxxxxxxxxxxxx5384500000008

[jackeichen]

By JEDEC spec:

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Per the definition of SSD in this specification, the SSD may replace or co-exist with hard disk drives(HDD's) in an application. To be consistent with the established IDEMA calculation for HDD capacitySSD capacity shall be defined as user-addressable capacity as calculated using the following formulasnonvolatile memory areas reserved for device use are not included in this calculation):

For a logical block size of 512 bytes:
User-addressable logical block count = 21168 +(1953504 x SSD Capacity in Gbytes); or
SSD Capacity in Gbytes = (User-addressable logical block count - 21168) /1953504.

For a logical block size of 4096 bytes:
User-addressable logical block count = 2646 +(244188 x Capacity in Gbytes); or
Capacity in Gbytes=(User-addressable logical block count -2646)/ 244188

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