NVMe-oF host configuration for RHEL 9.1 with ONTAP

12/19/2023 Contributors

NVMe over Fabrics or NVMe-oF (including NVMe/FC and NVMe/TCP) is supported with RHEL 9.1 with Asymmetric Namespace Access (ANA) that is required for surviving storage failovers (SFOs) on the ONTAP array. ANA is the asymmetric logical unit access (ALUA) equivalent in the NVMe-oF environment, and is currently implemented with in-kernel NVMe Multipath. This document contains the details for enabling NVMe-oF with in-kernel NVMe Multipath using ANA on RHEL 9.1 and ONTAP as the target.

The following support is available for the NVMe-oF host configuration for RHEL 9.1 with ONTAP:

Support for NVMe over TCP (NVMe/TCP) in addition to NVMe/FC. The NetApp plug-in in the native nvme-cli package displays ONTAP details for both NVMe/FC and NVMe/TCP namespaces.
Use of NVMe and SCSI co-existent traffic on the same host on a given host bus adapter (HBA), without the explicit dm-multipath settings to prevent claiming NVMe namespaces.

Refer to the NetApp Interoperability Matrix Tool for accurate details regarding supported configurations.

Features

RHEL 9.1 includes support for in-kernel NVMe multipath for NVMe namespaces enabled by default, without the need for explicit settings.

Known limitations

SAN booting using the NVMe-oF protocol is currently not supported.

Enable in-kernel NVMe multipath

You can use the following procedure to enable in-kernel NVMe multipath.

Steps

Install RHEL 9.1 on the server.
After the installation is complete, verify that you are running the specified RHEL 9.1 kernel. See the NetApp Interoperability Matrix Tool for the most current list of supported versions.

Example:
```
# uname -r
 5.14.0-162.6.1.el9_1.x86_64
```

Install the nvme-cli package:

Example:

# rpm -qa|grep nvme-cli
nvme-cli-2.0-4.el9.x86_64

On the host, check the host NQN string at /etc/nvme/hostnqn and verify that it matches the host NQN string for the corresponding subsystem on the ONTAP array. Example:

# cat /etc/nvme/hostnqn
nqn.2014-08.org.nvmexpress:uuid:325e7554-1f9b-11ec-8489-3a68dd61a4df


::> vserver nvme subsystem host show -vserver vs_nvme207
Vserver     Subsystem       Host NQN
----------- --------------- ----------------------------------------------------------
vs_nvme207 rhel_207_LPe32002     nqn.2014-08.org.nvmexpress:uuid:325e7554-1f9b-11ec-8489-3a68dd61a4df

If the host NQN strings do not match, you should use the vserver modify command to update the host NQN string on your corresponding ONTAP NVMe subsystem to match the host NQN string /etc/nvme/hostnqn on the host.

Reboot the host.

Configure NVMe/FC

You can configure NVMe/FC for Broadcom/Emulex or Marvell/Qlogic adapters.

Broadcom/Emulex

Steps

Verify that you are using the supported adapter. See the NetApp Interoperability Matrix Tool for the most current list of supported adapters.

# cat /sys/class/scsi_host/host*/modelname
LPe32002-M2
LPe32002-M2

# cat /sys/class/scsi_host/host*/modeldesc

Emulex LightPulse LPe32002-M2 2-Port 32Gb Fibre Channel Adapter
Emulex LightPulse LPe32002-M2 2-Port 32Gb Fibre Channel Adapter

Verify that you are using the recommended Broadcom lpfc firmware and inbox driver. See the NetApp Interoperability Matrix Tool for the most current list of supported adapter driver and firmware versions.
```
# cat /sys/class/scsi_host/host*/fwrev
14.0.505.11, sli-4:2:c
14.0.505.11, sli-4:2:c
```
```
# cat /sys/module/lpfc/version
0:14.2.0.5
```

Verify that lpfc_enable_fc4_type is set to 3

# cat /sys/module/lpfc/parameters/lpfc_enable_fc4_type
3

Verify that the initiator ports are up and running, and that you can see the target LIFs.

# cat /sys/class/fc_host/host*/port_name
0x100000109b1b95ef
0x100000109b1b95f0

# cat /sys/class/fc_host/host*/port_state
Online
Online

# cat /sys/class/scsi_host/host*/nvme_info
NVME Initiator Enabled
XRI Dist lpfc0 Total 6144 IO 5894 ELS 250
NVME LPORT lpfc0 WWPN x100000109b1b95ef WWNN x200000109b1b95ef DID x061700 ONLINE
NVME RPORT       WWPN x2035d039ea1308e5 WWNN x2082d039ea1308e5 DID x062f05 TARGET DISCSRVC ONLINE
NVME RPORT       WWPN x2083d039ea1308e5 WWNN x2082d039ea1308e5 DID x062407 TARGET DISCSRVC ONLINE

NVME Statistics
LS: Xmt 000000000e Cmpl 000000000e Abort 00000000
LS XMIT: Err 00000000  CMPL: xb 00000000 Err 00000000
Total FCP Cmpl 000000000001df6c Issue 000000000001df6e OutIO 0000000000000002
        abort 00000000 noxri 00000000 nondlp 00000000 qdepth 00000000 wqerr 00000000 err 00000000
FCP CMPL: xb 00000000 Err 00000004

NVME Initiator Enabled
XRI Dist lpfc1 Total 6144 IO 5894 ELS 250
NVME LPORT lpfc1 WWPN x100000109b1b95f0 WWNN x200000109b1b95f0 DID x061400 ONLINE
NVME RPORT       WWPN x2036d039ea1308e5 WWNN x2082d039ea1308e5 DID x061605 TARGET DISCSRVC ONLINE
NVME RPORT       WWPN x2037d039ea1308e5 WWNN x2082d039ea1308e5 DID x062007 TARGET DISCSRVC ONLINE

NVME Statistics
LS: Xmt 000000000e Cmpl 000000000e Abort 00000000
LS XMIT: Err 00000000  CMPL: xb 00000000 Err 00000000
Total FCP Cmpl 000000000001dd28 Issue 000000000001dd29 OutIO 0000000000000001
        abort 00000000 noxri 00000000 nondlp 00000000 qdepth 00000000 wqerr 00000000 err 00000000
FCP CMPL: xb 00000000 Err 00000004

Marvell/QLogic FC adapter for NVMe/FC

The native inbox qla2xxx driver included in the RHEL 9.1 kernel has the latest fixes which are essential for ONTAP support.

Steps

Verify that you are running the supported adapter driver and firmware versions using the following command:

# cat /sys/class/fc_host/host*/symbolic_name
QLE2772 FW:v9.08.02 DVR:v10.02.07.400-k-debug
QLE2772 FW:v9.08.02 DVR:v10.02.07.400-k-debug

Verify ql2xnvmeenable is set which enables the Marvell adapter to function as an NVMe/FC initiator using the following command:
```
# cat /sys/module/qla2xxx/parameters/ql2xnvmeenable
1
```

Enable 1MB I/O (Optional)

ONTAP reports an MDTS (Max Data Transfer Size) of 8 in the Identify Controller data which means the maximum I/O request size can be up to 1MB. However, to issue I/O requests of size 1 MB for a Broadcom NVMe/FC host, you must increase the lpfc value of the lpfc_sg_seg_cnt parameter to 256 from the default value of 64.

Steps

Set the lpfc_sg_seg_cnt parameter to 256.

# cat /etc/modprobe.d/lpfc.conf
options lpfc lpfc_sg_seg_cnt=256

Run a dracut -f command, and reboot the host.

Verify that lpfc_sg_seg_cnt is 256.

# cat /sys/module/lpfc/parameters/lpfc_sg_seg_cnt
256

This is not applicable to Qlogic NVMe/FC hosts.

Configure NVMe/TCP

NVMe/TCP does not have auto-connect functionality. Therefore, if a path goes down and is not reinstated within the default time out period of 10 minutes, NVMe/TCP cannot automatically reconnect. To prevent a time out, you should set the retry period for failover events to at least 30 minutes.

Steps

Verify whether the initiator port can fetch the discovery log page data across the supported NVMe/TCP LIFs:

# nvme discover -t tcp -w 192.168.1.8 -a 192.168.1.51

Discovery Log Number of Records 10, Generation counter 119
=====Discovery Log Entry 0======
trtype: tcp
adrfam: ipv4
subtype: nvme subsystem
treq: not specified
portid: 0
trsvcid: 4420
subnqn: nqn.1992-08.com.netapp:sn.56e362e9bb4f11ebbaded039ea165abc:subsystem.nvme_118_tcp_1
traddr: 192.168.2.56
sectype: none
=====Discovery Log Entry 1======
trtype: tcp
adrfam: ipv4
subtype: nvme subsystem
treq: not specified
portid: 1
trsvcid: 4420
subnqn: nqn.1992-08.com.netapp:sn.56e362e9bb4f11ebbaded039ea165abc:subsystem.nvme_118_tcp_1
traddr: 192.168.1.51
sectype: none
=====Discovery Log Entry 2======
trtype: tcp
adrfam: ipv4
subtype: nvme subsystem
treq: not specified
portid: 0
trsvcid: 4420
subnqn: nqn.1992-08.com.netapp:sn.56e362e9bb4f11ebbaded039ea165abc:subsystem.nvme_118_tcp_2
traddr: 192.168.2.56
sectype: none
...

Verify that the other NVMe/TCP initiator-target LIF combos can successfully fetch discovery log page data. For example:

# nvme discover -t tcp -w 192.168.1.8 -a 192.168.1.51
# nvme discover -t tcp -w 192.168.1.8 -a 192.168.1.52
# nvme discover -t tcp -w 192.168.2.9 -a 192.168.2.56
# nvme discover -t tcp -w 192.168.2.9 -a 192.168.2.57

Run nvme connect-all command across all the supported NVMe/TCP initiator-target LIFs across the nodes. Make sure you set a longer ctrl_loss_tmo timer retry period (for example, 30 minutes, which can be set through -l 1800) while running the connect-all command so that it would retry for a longer period of time in the event of a path loss. For example:
```
# nvme connect-all -t tcp -w 192.168.1.8 -a 192.168.1.51 -l 1800
# nvme connect-all -t tcp -w 192.168.1.8 -a 192.168.1.52 -l 1800
# nvme connect-all -t tcp -w 192.168.2.9 -a 192.168.2.56 -l 1800
# nvme connect-all -t tcp -w 192.168.2.9 -a 192.168.2.57 -l 1800
```

Validate NVMe-oF

You can use the following procedure to validate NVMe-oF.

Steps

Verify that in-kernel NVMe multipath is indeed enabled by checking:
```
# cat /sys/module/nvme_core/parameters/multipath
Y
```
Verify that the appropriate NVMe-oF settings (such as, model set to NetApp ONTAP Controller and load balancing iopolicy set to round-robin) for the respective ONTAP namespaces properly reflect on the host:
```
# cat /sys/class/nvme-subsystem/nvme-subsys*/model
NetApp ONTAP Controller
NetApp ONTAP Controller
```
```
# cat /sys/class/nvme-subsystem/nvme-subsys*/iopolicy
round-robin
round-robin
```

Verify that the ONTAP namespaces properly reflect on the host. For example:

# nvme list
Node           SN                    Model                   Namespace
------------   --------------------- ---------------------------------
/dev/nvme0n1   81CZ5BQuUNfGAAAAAAAB   NetApp ONTAP Controller   1

Usage                Format         FW Rev
-------------------  -----------    --------
85.90 GB / 85.90 GB  4 KiB + 0 B    FFFFFFFF

Verify that the controller state of each path is live and has proper ANA status. For example:

Example (a):

# nvme list-subsys /dev/nvme0n1
nvme-subsys10 - NQN=nqn.1992-08.com.netapp:sn.82e7f9edc72311ec8187d039ea14107d:subsystem.rhel_131_QLe2742
\
 +- nvme2 fc traddr=nn-0x2038d039ea1308e5:pn-0x2039d039ea1308e5,host_traddr=nn-0x20000024ff171d30:pn-0x21000024ff171d30 live non-optimized
 +- nvme3 fc traddr=nn-0x2038d039ea1308e5:pn-0x203cd039ea1308e5,host_traddr=nn-0x20000024ff171d31:pn-0x21000024ff171d31 live optimized
 +- nvme4 fc traddr=nn-0x2038d039ea1308e5:pn-0x203bd039ea1308e5,host_traddr=nn-0x20000024ff171d30:pn-0x21000024ff171d30 live optimized
 +- nvme5 fc traddr=nn-0x2038d039ea1308e5:pn-0x203ad039ea1308e5,host_traddr=nn-0x20000024ff171d31:pn-0x21000024ff171d31 live non-optimized

Example (b):

# nvme list-subsys /dev/nvme0n1
nvme-subsys1 - NQN=nqn.1992-08.com.netapp:sn.bf0691a7c74411ec8187d039ea14107d:subsystem.rhel_tcp_133
\
 +- nvme1 tcp traddr=192.168.166.21,trsvcid=4420,host_traddr=192.168.166.5 live non-optimized
 +- nvme2 tcp traddr=192.168.166.20,trsvcid=4420,host_traddr=192.168.166.5 live optimized
 +- nvme3 tcp traddr=192.168.167.21,trsvcid=4420,host_traddr=192.168.167.5 live non-optimized
 +- nvme4 tcp traddr=192.168.167.20,trsvcid=4420,host_traddr=192.168.167.5 live optimized

Verify that the NetApp plug-in displays proper values for each ONTAP namespace device.

Example (a):

# nvme netapp ontapdevices -o column
Device       Vserver          Namespace Path
---------    -------          --------------------------------------------------
/dev/nvme0n1 vs_tcp79     /vol/vol1/ns1 

NSID  UUID                                   Size
----  ------------------------------         ------
1     79c2c569-b7fa-42d5-b870-d9d6d7e5fa84  21.47GB


# nvme netapp ontapdevices -o json
{

  "ONTAPdevices" : [
  {

      "Device" : "/dev/nvme0n1",
      "Vserver" : "vs_tcp79",
      "Namespace_Path" : "/vol/vol1/ns1",
      "NSID" : 1,
      "UUID" : "79c2c569-b7fa-42d5-b870-d9d6d7e5fa84",
      "Size" : "21.47GB",
      "LBA_Data_Size" : 4096,
      "Namespace_Size" : 5242880
    },

]

}

Example (b):

# nvme netapp ontapdevices -o column

Device           Vserver                   Namespace Path
---------------- ------------------------- -----------------------------------
/dev/nvme1n1     vs_tcp_133                /vol/vol1/ns1

NSID UUID                                   Size
-------------------------------------------------------
1    1ef7cb56-bfed-43c1-97c1-ef22eeb92657   21.47GB

# nvme netapp ontapdevices -o json
{
  "ONTAPdevices":[
    {
      "Device":"/dev/nvme1n1",
      "Vserver":"vs_tcp_133",
      "Namespace_Path":"/vol/vol1/ns1",
      "NSID":1,
      "UUID":"1ef7cb56-bfed-43c1-97c1-ef22eeb92657",
      "Size":"21.47GB",
      "LBA_Data_Size":4096,
      "Namespace_Size":5242880
    },
  ]

}

Known issues

The NVMe-oF host configuration for RHEL 9.1 with ONTAP has the following known issues:

NetApp Bug ID Title Description Bugzilla ID

NetApp Bug ID	Title	Description	Bugzilla ID
1503468	`nvme list-subsys` command returns repeated nvme controller list for a given subsystem	The `nvme list-subsys` command should return a unique list of nvme controllers associated to a given subsystem. In RHEL 9.1, the `nvme list-subsys` command returns nvme controllers with its respective ANA state for all namespaces that belong to a given subsystem. However, the ANA state is a per-namespace attribute therefore, it would be ideal to display unique nvme controller entries with the path state if you list the subsystem command syntax for a given namespace.	2130106

1503468

nvme list-subsys command returns repeated nvme controller list for a given subsystem

The nvme list-subsys command should return a unique list of nvme controllers associated to a given subsystem. In RHEL 9.1, the nvme list-subsys command returns nvme controllers with its respective ANA state for all namespaces that belong to a given subsystem. However, the ANA state is a per-namespace attribute therefore, it would be ideal to display unique nvme controller entries with the path state if you list the subsystem command syntax for a given namespace.

2130106

NVMe-oF host configuration for RHEL 9.1 with ONTAP

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Features

Known limitations

Enable in-kernel NVMe multipath

Configure NVMe/FC

Enable 1MB I/O (Optional)

Configure NVMe/TCP

Validate NVMe-oF

Known issues