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NVMe-oF host configuration for RHEL 9.0 with ONTAP

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NVMe-oF (including NVMe/FC and NVMe/TCP) is supported with RHEL 9.0 with Asymmetric Namespace Access (ANA) required for surviving storage failovers (SFOs) on the ONTAP array. ANA is the ALUA equivalent in the NVM-oF environment, and is currently implemented with in-kernel NVMe Multipath. Using this procedure, you can enable NVMe-oF with in-kernel NVMe Multipath using ANA on RHEL 9.0 and ONTAP as the target.

For additional details on supported configurations, see the NetApp Interoperability Matrix Tool.

Features

  • Beginning with RHEL 9.0, NVMe/TCP is no longer a technology preview feature (unlike RHEL 8) but a fully supported enterprise feature itself.

  • Beginning with RHEL 9.0, in-kernel NVMe multipath is enabled for NVMe namespaces by default, without the need for explicit settings (unlike RHEL 8).

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

  1. Install RHEL 9.0 on the server.

  2. After the installation is complete, verify that you are running the specified RHEL 9.0 kernel. See NetApp Interoperability Matrix for the most current list of supported versions.

    # uname -r
5.14.0-70.13.1.el9_0.x86_64

  3. Install the nvme-cli package.

    # rpm -qa|grep nvme-cli
nvme-cli-1.16-3.el9.x86_64

  4. 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. For example,

    # cat /etc/nvme/hostnqn
nqn.2014-08.org.nvmexpress:uuid:9ed5b327-b9fc-4cf5-97b3-1b5d986345d1
    ::> vserver nvme subsystem host show -vserver vs_fcnvme_141
Vserver     Subsystem Host     NQN
----------- --------------- ----------------------------------------------------------
vs_fcnvme_14 nvme_141_1 nqn.2014-08.org.nvmexpress:uuid:9ed5b327-b9fc-4cf5-97b3-1b5d986345d1
    Note 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 from /etc/nvme/hostnqn on the host.

  5. Reboot the host.

Configure NVMe/FC

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

Broadcom/Emulex
Steps

  1. Verify that you are using the supported adapter. For additional details on supported adapters, see the NetApp Interoperability Matrix Tool.

    # 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

  2. Verify that you are using the recommended Broadcom lpfc firmware and inbox driver. For the most current list of supported adapter driver and firmware versions, see NetApp Interoperability Matrix.

    # cat /sys/class/scsi_host/host*/fwrev
12.8.351.47, sli-4:2:c
12.8.351.47, sli-4:2:c
    # cat /sys/module/lpfc/version
0:14.0.0.4

  3. Verify that lpfc_enable_fc4_type is set to 3.

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

  4. Verify that the initiator ports are up and running, and you are able to see the target LIFs.

    # cat /sys/class/fc_host/host*/port_name
0x100000109b1c1204
0x100000109b1c1205
    # 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 x100000109b1c1204 WWNN x200000109b1c1204 DID x011d00 ONLINE
NVME RPORT WWPN x203800a098dfdd91 WWNN x203700a098dfdd91 DID x010c07 TARGET DISCSRVC ONLINE
NVME RPORT WWPN x203900a098dfdd91 WWNN x203700a098dfdd91 DID x011507 TARGET DISCSRVC ONLINE

NVME Statistics
LS: Xmt 0000000f78 Cmpl 0000000f78 Abort 00000000
LS XMIT: Err 00000000 CMPL: xb 00000000 Err 00000000
Total FCP Cmpl 000000002fe29bba Issue 000000002fe29bc4 OutIO 000000000000000a
abort 00001bc7 noxri 00000000 nondlp 00000000 qdepth 00000000 wqerr 00000000 err 00000000
FCP CMPL: xb 00001e15 Err 0000d906

NVME Initiator Enabled
XRI Dist lpfc1 Total 6144 IO 5894 ELS 250
NVME LPORT lpfc1 WWPN x100000109b1c1205 WWNN x200000109b1c1205 DID x011900 ONLINE
NVME RPORT WWPN x203d00a098dfdd91 WWNN x203700a098dfdd91 DID x010007 TARGET DISCSRVC ONLINE
NVME RPORT WWPN x203a00a098dfdd91 WWNN x203700a098dfdd91 DID x012a07 TARGET DISCSRVC ONLINE

NVME Statistics
LS: Xmt 0000000fa8 Cmpl 0000000fa8 Abort 00000000
LS XMIT: Err 00000000 CMPL: xb 00000000 Err 00000000
Total FCP Cmpl 000000002e14f170 Issue 000000002e14f17a OutIO 000000000000000a
abort 000016bb noxri 00000000 nondlp 00000000 qdepth 00000000 wqerr 00000000 err 00000000
FCP CMPL: xb 00001f50 Err 0000d9f8
Marvell/QLogic

The native inbox qla2xxx driver included in the RHEL 9.0 kernel has the latest fixes. These fixes are essential for ONTAP support.

Steps

  1. Verify that you are running the supported adapter driver and firmware versions:

# cat /sys/class/fc_host/host*/symbolic_name
QLE2742 FW:v9.06.02 DVR:v10.02.00.200-k
QLE2742 FW:v9.06.02 DVR:v10.02.00.200-k

  1. Verify ql2xnvmeenable is set which enables the Marvell adapter to function as a NVMe/FC initiator:

# 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. This means the maximum I/O request size can be up to 1MB. 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.

Note The following steps don't apply to Qlogic NVMe/FC hosts.
Steps

  1. Set the lpfc_sg_seg_cnt parameter to 256:

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

  2. Run the dracut -f command, and reboot the host:

  3. Verify that lpfc_sg_seg_cnt is 256:

    cat /sys/module/lpfc/parameters/lpfc_sg_seg_cnt

    The expected value is 256.

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

  1. Verify whether the initiator port is able to fetch 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
...

  2. Similarly, verify that the other NVMe/TCP initiator-target LIF combos are able to successfully fetch the 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

  3. Run nvme connect-all command across all the supported NVMe/TCP initiator-target LIFs across the nodes. Ensure you set a longer ctrl_loss_tmo timer retry period (for example, 30 minutes, which can be set through -l 1800) during the connect-all 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

  1. Verify that in-kernel NVMe multipath is indeed enabled by checking:

    # cat /sys/module/nvme_core/parameters/multipath
Y

  2. Verify that the appropriate NVMf settings (for example, 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

  3. Verify that the ONTAP namespaces properly reflect on the host.

    Example (a):

    # nvme list
Node         SN                    Model                   Namespace   Usage
------      ---------------------------------------      ------------------------
/dev/nvme0n1 814vWBNRwf9HAAAAAAAB  NetApp ONTAP Controller  1          85.90 GB / 85.90 GB

Format         FW Rev
---------------------
4 KiB + 0 B   FFFFFFFF

    Example (b):

    # nvme list
Node           SN                   Model                    Namespace   Usage
---------------------------------------------------- ------------------------------------
/dev/nvme0n1   81CZ5BQuUNfGAAAAAAAB NetApp ONTAP Controller   1         85.90 GB / 85.90 GB

Format         FW Rev
-----------------------
4 KiB + 0 B   FFFFFFFF

  4. Verify that the controller state of each path is live and has a proper ANA status.

    Example (a):

    # nvme list-subsys /dev/nvme0n1
nvme-subsys0 - NQN=nqn.1992-08.com.netapp:sn.5f5f2c4aa73b11e9967e00a098df41bd:subsystem.nvme_141_1
\
+- nvme0 fc traddr=nn-0x203700a098dfdd91:pn-0x203800a098dfdd91 host_traddr=nn-0x200000109b1c1204:pn-0x100000109b1c1204 live inaccessible
+- nvme1 fc traddr=nn-0x203700a098dfdd91:pn-0x203900a098dfdd91 host_traddr=nn-0x200000109b1c1204:pn-0x100000109b1c1204 live inaccessible
+- nvme2 fc traddr=nn-0x203700a098dfdd91:pn-0x203a00a098dfdd91 host_traddr=nn-0x200000109b1c1205:pn-0x100000109b1c1205 live optimized
+- nvme3 fc traddr=nn-0x203700a098dfdd91:pn-0x203d00a098dfdd91 host_traddr=nn-0x200000109b1c1205:pn-0x100000109b1c1205 live optimized

    Example (b):

    # nvme list-subsys /dev/nvme0n1
nvme-subsys0 - NQN=nqn.1992-08.com.netapp:sn.56e362e9bb4f11ebbaded039ea165abc:subsystem.nvme_118_tcp_1
\
+- nvme0 tcp traddr=192.168.1.51 trsvcid=4420 host_traddr=192.168.1.8 live optimized
+- nvme10 tcp traddr=192.168.2.56 trsvcid=4420 host_traddr=192.168.2.9 live optimized
+- nvme15 tcp traddr=192.168.2.57 trsvcid=4420 host_traddr=192.168.2.9 live non-optimized
+- nvme5 tcp traddr=192.168.1.52 trsvcid=4420 host_traddr=192.168.1.8 live non-optimized

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

    Example (a):

    # nvme netapp ontapdevices -o column
Device       Vserver        Namespace Path                            NSID
----------------------- ------------------------------ -------------------------
/dev/nvme0n1  vs_fcnvme_141  /vol/fcnvme_141_vol_1_1_0/fcnvme_141_ns   1

UUID                                   Size
--------------------------------------------
72b887b1-5fb6-47b8-be0b-33326e2542e2   85.90GB
    # nvme netapp ontapdevices -o json
{
"ONTAPdevices" : [
    {
        "Device" : "/dev/nvme0n1",
        "Vserver" : "vs_fcnvme_141",
        "Namespace_Path" : "/vol/fcnvme_141_vol_1_1_0/fcnvme_141_ns",
        "NSID" : 1,
        "UUID" : "72b887b1-5fb6-47b8-be0b-33326e2542e2",
        "Size" : "85.90GB",
        "LBA_Data_Size" : 4096,
        "Namespace_Size" : 20971520
    }
  ]
}

    Example (b):

    # nvme netapp ontapdevices -o column
Device               Vserver                   Namespace Path
--------------------- ------------------------- ------------------------------------
/dev/nvme0n1         vs_tcp_118                /vol/tcpnvme_118_1_0_0/tcpnvme_118_ns

NSID   UUID                               Size
-------------------------------------------------
1     4a3e89de-b239-45d8-be0c-b81f6418283c 85.90GB
    # nvme netapp ontapdevices -o json
{
"ONTAPdevices" : [
    {
     "Device" : "/dev/nvme0n1",
      "Vserver" : "vs_tcp_118",
      "Namespace_Path" : "/vol/tcpnvme_118_1_0_0/tcpnvme_118_ns",
      "NSID" : 1,
      "UUID" : "4a3e89de-b239-45d8-be0c-b81f6418283c",
      "Size" : "85.90GB",
      "LBA_Data_Size" : 4096,
      "Namespace_Size" : 20971520
    },
  ]

}

Known issues

The NVMe-oF host configuration for RHEL 9.0 with ONTAP has the following known issues:

NetApp Bug ID Title Description

1479047

RHEL 9.0 NVMe-oF hosts create duplicate Persistent Discovery Controllers

On NVMe over Fabrics (NVMe-oF) hosts, you can use the "nvme discover -p" command to create Persistent Discovery Controllers (PDCs). When this command is used, only one PDC should be created per initiator-target combination. However, if you are running ONTAP 9.10.1 and Red Hat Enterprise Linux (RHEL) 9.0 with an NVMe-oF host, a duplicate PDC is created each time "nvme discover -p" is executed. This leads to unnecessary usage of resources on both the host and the target.