Install SAN host utilities
Use Oracle Linux 7.6 with ONTAP
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You can use the ONTAP SAN host configuration settings to configure Oracle Linux 7.6 with ONTAP as the target.
Install the Linux Unified Host Utilities
The NetApp Linux Unified Host Utilities software package is available on the NetApp Support Site in a 32-bit and 64-bit .rpm file. If you do not know which file is right for your configuration, use the NetApp Interoperability Matrix Tool to verify which one you need.
NetApp strongly recommends installing the Linux Unified Host Utilities, but it is not mandatory. The utilities do not change any settings on your Linux host. The utilities improve management and assist NetApp customer support in gathering information about your configuration.
If you have a version of Linux Unified Host Utilities currently installed you should upgrade it or, you should remove it and use the following steps to install the latest version.
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Download the 32-bit or 64-bit Linux Unified Host Utilities software package from the NetApp Support Site Site to your host.
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Use the following command to install the software package:
rpm -ivh netapp_linux_unified_host_utilities-7-1.x86_64
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You can use the configuration settings provided in this document to configure cloud clients connected to Cloud Volumes ONTAP and Amazon FSx for ONTAP. |
SAN Toolkit
The toolkit is installed automatically when you install the NetApp Host Utilities package. This kit provides the sanlun utility, which helps you manage LUNs and HBAs. The sanlun command returns information about the LUNs mapped to your host, multipathing, and information necessary to create initiator groups.
In the following example, the sanlun lun show command returns LUN information.
# sanlun lun show allExample output:
controller(7mode/E-Series)/ device host lun vserver(cDOT/FlashRay) lun-pathname filename adapter protocol size Product ------------------------------------------------------------------------- data_vserver /vol/vol1/lun1 /dev/sdb host16 FCP 120.0g cDOT data_vserver /vol/vol1/lun1 /dev/sdc host15 FCP 120.0g cDOT data_vserver /vol/vol2/lun2 /dev/sdd host16 FCP 120.0g cDOT data_vserver /vol/vol2/lun2 /dev/sde host15 FCP 120.0g cDOT
SAN Booting
If you decide to use SAN booting, it must be supported by your configuration. You can use the NetApp Interoperability Matrix Tool to verify that your OS, HBA, HBA firmware and the HBA boot BIOS, and ONTAP version are supported.
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Map the SAN boot LUN to the host.
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Verify that multiple paths are available.
Multiple paths become available after the host OS is up and running on the paths. -
Enable SAN booting in the server BIOS for the ports to which the SAN boot LUN is mapped.
For information on how to enable the HBA BIOS, see your vendor-specific documentation.
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Reboot the host to verify that the boot is successful.
Multipathing
For Oracle Linux 7.6 the /etc/multipath.conf file must exist, but you do not need to make specific changes to the file. Oracle Linux 7.6 is compiled with all settings required to recognize and correctly manage ONTAP LUNs.
You can use the multipath -ll command to verify the settings for your ONTAP LUNs.
There should be two groups of paths with different priorities. The paths with the higher priorities are Active/Optimized, which means they are serviced by the controller where the aggregate is located. The paths with the lower priorities are active but are non-optimized because they are served from a different controller. The non-optimized paths are only used when no optimized paths are available.
The following example displays the correct output for an ONTAP LUN with two Active/Optimized paths and two Active/non-Optimized paths:
# multipath -ll 3600a09803831347657244e527766394e dm-5 NETAPP,LUN C-Mode size=80G features='4 queue_if_no_path pg_init_retries 50 retain_attached_hw_handle' hwhandler='1 alua' wp=rw |-+- policy='service-time 0' prio=50 status=active | |- 11:0:1:0 sdj 8:144 active ready running | |- 11:0:2:0 sdr 65:16 active ready running |-+- policy='service-time 0' prio=10 status=enabled |- 11:0:0:0 sdb 8:i6 active ready running |- 12:0:0:0 sdz 65:144 active ready running
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Do not use an excessive number of paths to a single LUN. No more than four paths should be required. More than eight paths might cause path issues during storage failures. |
Recommended Settings
The Oracle Linux 7.6 OS is compiled to recognize ONTAP LUNs and automatically set all configuration parameters correctly.
The multipath.conf file must exist for the multipath daemon to start, but you can create an empty, zero-byte file by using the following command:
touch /etc/multipath.conf
The first time you create this file, you might need to enable and start the multipath services:
# systemctl enable multipathd # systemctl start multipathd
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There is no requirement to add anything directly to the
multipath.conffile, unless you have devices that you do not want to be managed by multipath or you have existing settings that override defaults. -
To exclude unwanted devices, add the following syntax to the
multipath.conffile .blacklist { wwid <DevId> devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*" devnode "^hd[a-z]" devnode "^cciss.*" }Replace the
<DevId>with theWWIDstring of the device you want to exclude.ExampleIn this example, we are going to determine the WWID of a device and add to the
multipath.conffile.Steps-
Run the following command to determine the WWID:
# /lib/udev/scsi_id -gud /dev/sda 360030057024d0730239134810c0cb833
sdais the local SCSI disk that we need to add it to the blacklist. -
Add the
WWIDto the blacklist stanza in/etc/multipath.conf:blacklist { wwid 360030057024d0730239134810c0cb833 devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*" devnode "^hd[a-z]" devnode "^cciss.*" }
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You should always check your /etc/multipath.conf file for legacy settings, especially in the defaults section, that might be overriding the default settings.
The following table demonstrates the critical multipathd parameters for ONTAP LUNs and the required values. If a host is connected to LUNs from other vendors and any of these parameters are overridden, they will need to be corrected by later stanzas in the multipath.conf file that apply specifically to ONTAP LUNs. If this is not done, the ONTAP LUNs might not work as expected. These defaults should only be overridden in consultation with NetApp and/or an OS vendor and only when the impact is fully understood.
| Parameter | Setting |
|---|---|
detect_prio |
yes |
dev_loss_tmo |
"infinity" |
failback |
immediate |
fast_io_fail_tmo |
5 |
features |
"3 queue_if_no_path pg_init_retries 50" |
flush_on_last_del |
"yes" |
hardware_handler |
"0" |
path_checker |
"tur" |
path_grouping_policy |
"group_by_prio" |
path_selector |
"service-time 0" |
polling_interval |
5 |
prio |
"ontap" |
product |
LUN.* |
retain_attached_hw_handler |
yes |
rr_weight |
"uniform" |
user_friendly_names |
no |
vendor |
NETAPP |
The following example shows how to correct an overridden default. In this case, the multipath.conf file defines values for path_checker and detect_prio that are not compatible with ONTAP LUNs. If they cannot be removed because of other SAN arrays still attached to the host, these parameters can be corrected specifically for ONTAP LUNs with a device stanza.
defaults {
path_checker readsector0
detect_prio no
}
devices {
device {
vendor "NETAPP "
product "LUN.*"
path_checker tur
detect_prio yes
}
}
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To configure Oracle Linux 7.6 RedHat Enterprise Kernel (RHCK), use the recommended settings for Red Hat Enterprise Linux (RHEL) 7.6. |
Known issues
The Oracle Linux 7.6 with ONTAP release has the following known issues:
| NetApp Bug ID | Title | Description | Bugzilla ID |
|---|---|---|---|
1440718 |
If you unmap or map a LUN without performing a SCSI rescan, it might lead to data corruption on the host. |
When you set the 'disable_changed_wwids' multipath configuration parameter to YES, it disables access to the path device in the event of a WWID change. Multipath will disable access to the path device until the WWID of the path is restored to the WWID of the multipath device. To learn more, see NetApp Knowledge Base: The filesystem corruption on iSCSI LUN on the Oracle Linux 7. |
N/A |
LUNs might not be available during host discovery due to "Not Present" state of remote ports on a OL7U6 host with QLogic QLE2742 adapter |
During host discovery, the status of Fibre Channel (FC) remote ports on a OL7U6 host with a QLogic QLE2742 adapter might enter into "Not Present" state. Remote ports with a "Not Present" state might cause paths to LUNs to become unavailable. During storage failover, the path redundancy might be reduced and result in an I/O outage. |
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Kernel disruption occurs on Oracle Linux 7.6 running with Qlogic(QLE2672) 16GB FC HBA during storage failover operations |
During storage failover operations on the Oracle Linux 7.6 with a Qlogic QLE2672 Fibre Channel (FC) host bus adapter (HBA), a kernel disruption occurs due to a panic in the kernel. The kernel panic causes Oracle Linux 7.6 to reboot, which leads to an application disruption. If the kdump mechanism is enabled, the kernel panic generates a vmcore file located in the /var/crash/ directory. You can analyze the vmcore file to determine the cause of the panic. After the kernel disruption, you can reboot the host OS and recover the operating system, and then you can restart any applications as required. |
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Kernel disruption might occur on Oracle Linux 7.6 running with Qlogic(QLE2742) 32GB FC HBA during storage failover operations |
During storage failover operations on the Oracle Linux 7.6 with a Qlogic QLE2742 Fibre Channel (FC) host bus adapter (HBA), a kernel disruption might occur due to a panic in the kernel. The kernel panic causes Oracle Linux 7.6 to reboot, which leads to an application disruption. If the kdump mechanism is enabled, the kernel panic generates a vmcore file located in the /var/crash/ directory. You can analyze the vmcore file to determine the cause of the panic. |
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Kernel disruption might occur on Oracle Linux 7.6 running with Emulex (LPe32002-M2)32GB FC HBA during storage failover operations |
During storage failover operations on the Oracle Linux 7.6 with an Emulex LPe32002-M2 Fibre Channel (FC) host bus adapter (HBA), a kernel disruption might occur due to a panic in the kernel. The kernel panic causes Oracle Linux 7.6 to reboot, which leads to an application disruption. |
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No I/O progress on Oracle Linux 7.6 with UEK5U2 kernel, running with an Emulex LPe16002B-M6 16G FC HBA during storage failover operations |
During storage failover operations on the Oracle Linux 7.6 with the UEK5U2 kernel running with an Emulex LPe16002B-M6 16G Fibre Channel (FC) host bus adapter (HBA), I/O progress might stop due to reports getting blocked. The storage failover operation reports change from an "online" state to a "blocked" state, causing a delay in read and write operations. After the operation has completed successfully, the reports fail to move back to an "online" state and continue to remain in a "blocked" state. |
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Remote port status on QLogic QLE2672 16G host blocked during storage failover operations |
Fibre Channel (FC) remote ports might be blocked on Red Hat Enterprise Linux (RHEL) 7.6 with the QLogic QLE2672 16G host during storage failover operations. Because the logical interfaces go down when a storage node is down, the remote ports set the storage node status to blocked. IO progress might stop due to the blocked ports if you are running both a QLogic QLE2672 16G host and a QLE2742 32GB Fibre Channel (FC) host bus adapter (HBA). |