NVMe: Difference between revisions

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*[https://www.computerweekly.com/feature/NVMe-over-TCP-brings-super-fast-flash-over-standard-IP-networks NVMe over TCP]
*[https://www.computerweekly.com/feature/NVMe-over-TCP-brings-super-fast-flash-over-standard-IP-networks NVMe over TCP]
*https://tekdeeps.com/what-is-nvme-over-tcp-how-to-use/
*https://tekdeeps.com/what-is-nvme-over-tcp-how-to-use/
*https://www.linuxjournal.com/content/data-flash-part-iii-nvme-over-fabrics-using-tcp
*[https://www.linuxjournal.com/content/data-flash-part-iii-nvme-over-fabrics-using-tcp Data in a Flash, Part III: NVMe over Fabrics Using TCP]
*[https://infohub.delltechnologies.com/l/nvme-nvme-tcp-and-dell-smartfabric-storage-software-overview-ip-san-solution-primer-1/nvme-tcp-storage-operations nvme-tcp storage operations]
*[https://infohub.delltechnologies.com/l/nvme-nvme-tcp-and-dell-smartfabric-storage-software-overview-ip-san-solution-primer-1/nvme-tcp-storage-operations nvme-tcp storage operations]
 
*[https://www.techtarget.com/searchstorage/post/NVMe-oF-over-IP-A-complete-SAN-platform NVMe-oF over IP: A complete SAN platform]
==Qemu and NVMe==
==Qemu and NVMe==
*[https://qemu-project.gitlab.io/qemu/system/devices/nvme.html Qemu and nvme]
*[https://qemu-project.gitlab.io/qemu/system/devices/nvme.html Qemu and nvme]
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===Slots===
===Slots===
====M.2====  
====M.2====  
The old way, on standard motherboards
The old way, on standard motherboards.
 
https://arstechnica.com/gadgets/2015/02/understanding-m-2-the-interface-that-will-speed-up-your-next-ssd/
 
====U.2====
====U.2====
*https://www.drewthorst.com/posts/nvme/namespaces/readme/
*https://www.drewthorst.com/posts/nvme/namespaces/readme/
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=Tools=
=Tools=
==nvme-cli==
==nvme-cli==
==nvmet-cli==
==nvmetcli==
NVMe target admin tool
 
https://github.com/JunxiongGuan/nvmetcli
https://github.com/JunxiongGuan/nvmetcli


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Means nvme device 0, namespace 2, partition 3
Means nvme device 0, namespace 2, partition 3
The first namespace, '''n1''', will always exist
The first namespace, '''n1''', will always exist
==NVMe multipathing==
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/managing_storage_devices/enabling-multipathing-on-nvme-devices_managing-storage-devices


==Namespaces==
==Namespaces==
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*[https://www.drewthorst.com/posts/nvme/namespaces/readme/ Drew Thorstensen - NVME namespaces]
*[https://www.drewthorst.com/posts/nvme/namespaces/readme/ Drew Thorstensen - NVME namespaces]
*https://narasimhan-v.github.io/2020/06/12/Managing-NVMe-Namespaces.html
*https://narasimhan-v.github.io/2020/06/12/Managing-NVMe-Namespaces.html
==NVMe over Fiber==
*[https://spdk.io/doc/nvmf.html NVMe-oF Target Getting Started Guide]


=HOWTO=
=HOWTO=
==On NVMe target==
===Deleting an nvme target===
NAME=nvmetest
PORT=1
NODENUM=1
cd /sys/kernel/config/nvmet
rm -rf ports/1/subsystems/$NAME
rmdir ports/$PORT
rmdir subsystems/$NAME-$NODENUM/namespaces/$PORT/
rmdir subsystems/$NAME-$NODENUM/
==List devices==
==List devices==
  nvme list
  nvme list
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get details
get details
  nvme id-ctrl /dev/nvme0
  nvme id-ctrl /dev/nvme0
if you want to find for example IP of a device:
if you want to find for example IP and NQN of a device:
  nvme list-subsys /dev/nvme2n1
  nvme list-subsys /dev/nvme2n1
of just
nvme list-subsys
==Show subnqn of device==
nvme id-ctrl /dev/nvme1n2 | grep subnqn


==Namespaces==
==Namespaces==


===Difference between size and capacity===
nsze vs ncap
flbas = blocksize
To check them in a namespace:
nvme id-ns /dev/nvme1n3 | egrep "nsze|ncap|flbas"
Get block size:
nvme id-ns /dev/nvme1n3 | grep "in use"
which gives like
lbaf  1 : ms:0  lbads:12 rp:0 (in use)
where lbads is the blocksize in 2^lbads, so in this case 2^12 = 4096
===Create namespace===
*[https://narasimhan-v.github.io/2020/06/12/Managing-NVMe-Namespaces.html Managing NVMe namespaces]
Get controller id
nvme id-ctrl /dev/nvme1 | grep cntlid
gives like
cntlid    : 0x1
Create 100G namespace, -s (--nsze) and -c (--ncap) is number of blocks -b, --blocksize
nvme create-ns /dev/nvme1 -s 26214387 -c 26214387 -b 4096
TODO: what about --flbas instead of blocksize?


To actually use the namespace you need to to attach it first
nvme attach-ns /dev/nvme1




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===Show unallocated capacity===
===Show unallocated capacity===
  nvme id-ctrl /dev/nvme1|grep '''unvmcap'''
  nvme id-ctrl /dev/nvme1|grep '''unvmcap'''


==NVMe over fabrics==
==NVMe over fabrics==
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Dependencies: python3-configshell-fb
Dependencies: python3-configshell-fb
===NVMe-oF target===
/bin/mount -t configfs none /sys/kernel/config/
====Show active targets====
?


===NVMe/TCP Host===
===NVMe/TCP Host===
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See [https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/9/html/managing_storage_devices/configuring-nvme-over-fabrics-using-nvme-tcp_managing-storage-devices#configuring-an-nvme-tcp-host_configuring-nvme-over-fabrics-using-nvme-tcp Configuring an NVMe/TCP host]
See [https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/9/html/managing_storage_devices/configuring-nvme-over-fabrics-using-nvme-tcp_managing-storage-devices#configuring-an-nvme-tcp-host_configuring-nvme-over-fabrics-using-nvme-tcp Configuring an NVMe/TCP host]


===Client===
==On Client==
Modules:
===Modules===
  nvme_rdma nvme_core nvme_fabrics and more
  nvme_rdma nvme_core nvme_fabrics and more


===Find shares on target===
nvme discover -t rdma -a 192.168.100.8 -s 4420
===Connect target===
nvme connect -t rdma -n "nqn.2016-06.io.spdk:cnode1" -a 192.168.100.8 -s 4420




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*[https://github.com/narbehaj/zabbix-nvme Monitoring nvme with zabbix]
*[https://github.com/narbehaj/zabbix-nvme Monitoring nvme with zabbix]
=Terms and acronyms=
==flbas==
Formatted LBA Sizes
==nlbaf==




=FAQ=
=FAQ=
==Failed to open /dev/nvme-fabrics: No such file or directory==
==Errors on client/host==
 
===Failed to open /dev/nvme-fabrics: No such file or directory===
  modprobe nvme-tcp
  modprobe nvme-tcp
or maybe rdma
or maybe rdma


==Failed to write to /dev/nvme-fabrics: Connection refused==
===Failed to write to /dev/nvme-fabrics: Connection refused===
dmesg will probably show
dmesg will probably show
  nvme0: failed to connect socket: -111
  nvme0: failed to connect socket: -111
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  nvme discover -t rdma ...
  nvme discover -t rdma ...


===Failed to write to /dev/nvme-fabrics: Input/output error===
Mayve you're trying to connect to a nonexisting nqn


==Failed to write to /dev/nvme-fabrics: Invalid argument==
==Failed to write to /dev/nvme-fabrics: Invalid argument==
 
Check dmesg
===nvme nvme0: Invalid MNAN value 1024===
===nvme nvme0: Invalid MNAN value 1024===
Try
Try
  modprobe nvme_core multipath=N
  modprobe nvme_core multipath=N
(remember to rmmod first :)
(remember to rmmod first :)




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Check your /etc/nvme/discover.conf, it should be '''rdma''' :)
Check your /etc/nvme/discover.conf, it should be '''rdma''' :)


==nvmet_tcp: malformed ip/port passed: :4420==
Maybe forgot to set addr_traddr ?
==Duplicate cntlid 1 with nvme0==
Make sure next connection is on new control id, /dev/nvme0x vs /dev/nvme1x
TODO ??
==IDs don't match for shared namespace 1==
??


[[Category:Storage]]
[[Category:Storage]]

Latest revision as of 10:56, 24 September 2024

NVM Express

Links

NVMe/TCP

Qemu and NVMe


Hardware

Slots

M.2

The old way, on standard motherboards.

https://arstechnica.com/gadgets/2015/02/understanding-m-2-the-interface-that-will-speed-up-your-next-ssd/

U.2

Hotplug

Tools

nvme-cli

nvmetcli

NVMe target admin tool

https://github.com/JunxiongGuan/nvmetcli

Documentation

NVMe device names

Example: /dev/nvme0n2p3

Means nvme device 0, namespace 2, partition 3 The first namespace, n1, will always exist

NVMe multipathing

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/managing_storage_devices/enabling-multipathing-on-nvme-devices_managing-storage-devices

Namespaces

MNAM: Maximum Number of Allowed Namespaces

NVMe over Fiber

HOWTO

On NVMe target

Deleting an nvme target

NAME=nvmetest
PORT=1
NODENUM=1
cd /sys/kernel/config/nvmet
rm -rf ports/1/subsystems/$NAME
rmdir ports/$PORT
rmdir subsystems/$NAME-$NODENUM/namespaces/$PORT/
rmdir subsystems/$NAME-$NODENUM/

List devices

nvme list

get details 

nvme id-ctrl /dev/nvme0

if you want to find for example IP and NQN of a device: 

nvme list-subsys /dev/nvme2n1

of just 

nvme list-subsys

Show subnqn of device

nvme id-ctrl /dev/nvme1n2 | grep subnqn

Namespaces

Difference between size and capacity

nsze vs ncap flbas = blocksize


To check them in a namespace: 

nvme id-ns /dev/nvme1n3 | egrep "nsze|ncap|flbas"

Get block size: 

nvme id-ns /dev/nvme1n3 | grep "in use"

which gives like 

lbaf  1 : ms:0   lbads:12 rp:0 (in use)

where lbads is the blocksize in 2^lbads, so in this case 2^12 = 4096

Create namespace

Get controller id 

nvme id-ctrl /dev/nvme1 | grep cntlid

gives like 

cntlid    : 0x1


Create 100G namespace, -s (--nsze) and -c (--ncap) is number of blocks -b, --blocksize 

nvme create-ns /dev/nvme1 -s 26214387 -c 26214387 -b 4096

TODO: what about --flbas instead of blocksize?

To actually use the namespace you need to to attach it first 

nvme attach-ns /dev/nvme1


List namespaces

nvme list-ns /dev/nvme1

Show info about namespace

nvme id-ns /dev/nvme1n1

Show number of available namespaces

nvme id-ctrl /dev/nvme1|grep nn


Show total capacity

nvme id-ctrl /dev/nvme1|grep tnvmcap

Show unallocated capacity

nvme id-ctrl /dev/nvme1|grep unvmcap

NVMe over fabrics

https://www.linuxjournal.com/content/data-flash-part-iii-nvme-over-fabrics-using-tcp

You might want to use nvmetcli on the target:

https://github.com/JunxiongGuan/nvmetcli

Dependencies: python3-configshell-fb

NVMe-oF target

/bin/mount -t configfs none /sys/kernel/config/

Show active targets

?

NVMe/TCP Host

In this context Host means client/initiator

See Configuring an NVMe/TCP host

On Client

Modules

nvme_rdma nvme_core nvme_fabrics and more


Find shares on target

nvme discover -t rdma -a 192.168.100.8 -s 4420


Connect target

nvme connect -t rdma -n "nqn.2016-06.io.spdk:cnode1" -a 192.168.100.8 -s 4420


Connect on boot

Check /etc/nvme/discovery.conf 

systemctl enable nvmf-autoconnect.service

Show remote connections

nvme list-subsys

Monitoring nvme

Terms and acronyms

flbas

Formatted LBA Sizes

nlbaf

FAQ

Errors on client/host

Failed to open /dev/nvme-fabrics: No such file or directory

modprobe nvme-tcp

or maybe rdma

Failed to write to /dev/nvme-fabrics: Connection refused

dmesg will probably show 

nvme0: failed to connect socket: -111

Maybe you're using something like infiniband, try 

nvme discover -t rdma ...


Failed to write to /dev/nvme-fabrics: Input/output error

Mayve you're trying to connect to a nonexisting nqn

Failed to write to /dev/nvme-fabrics: Invalid argument

Check dmesg

nvme nvme0: Invalid MNAN value 1024

Try 

modprobe nvme_core multipath=N

(remember to rmmod first :)


nvme_fabrics: no handler found for transport drma.

Check your /etc/nvme/discover.conf, it should be rdma :)

nvmet_tcp: malformed ip/port passed: :4420

Maybe forgot to set addr_traddr ?


Duplicate cntlid 1 with nvme0

Make sure next connection is on new control id, /dev/nvme0x vs /dev/nvme1x TODO ??

IDs don't match for shared namespace 1

??

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