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SAN hosts and cloud clients

Use Oracle Linux 8.8 with ONTAP

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You can use the ONTAP SAN host configuration settings to configure Oracle Linux 8.8 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 64-bit .rpm file.

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 either upgrade it, or remove it and follow these steps to install the latest version.

Steps

  1. Download the 64-bit Linux Unified Host Utilities software package from the NetApp Support Site to your host.

  2. Install the software package:

    rpm -ivh netapp_linux_unified_host_utilities-7-1.x86_64

SAN toolkit

The tool kit is installed automatically when you install the NetApp Host Utilities package. This kit provides the sanlun utility, which helps you manage LUNs and host bus adapters (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 all
Example 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       80.0g  cDOT
data_vserver          /vol/vol1/lun1   /dev/sdc   host15   FCP       80.0g  cDOT
data_vserver          /vol/vol2/lun2   /dev/sdd   host16   FCP       80.0g  cDOT
data_vserver          /vol/vol2/lun2   /dev/sde   host15   FCP       80.0g  cDOT

SAN booting

What you'll need

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.

Steps

  1. Map the SAN boot LUN to the host.

  2. Verify that multiple paths are available.

    Note Multiple paths become available after the host OS is up and running on the paths.

  3. 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.

  4. Reboot the host to verify that the boot was successful.

Multipathing

For Oracle Linux (OL) 8.8 the /etc/multipath.conf file must exist, but you do not need to make specific changes to the file. OL 8.8 is compiled with all the settings required to recognize and correctly manage ONTAP LUNs.

You can use the multipath -ll command to verify the settings for your ONTAP LUNs.

The following sections provide sample multipath outputs for a LUN mapped to ASA and non-ASA configurations.

All SAN Array configurations

In All SAN Array (ASA) configurations, all paths to a given LUN are active and optimized. This improves performance by serving I/O operations through all paths at the same time.

Example

The following example displays the correct output for an ONTAP LUN:

# multipath -ll
3600a098038303634722b4d59646c4436 dm-28 NETAPP,LUN C-Mode
size=10G features='3 queue_if_no_path pg_init_retries 50' hwhandler='1 alua' wp=rw
|-+- policy='service-time 0' prio=50 status=active
  |- 11:0:7:6   sdbz 68:208  active ready running
  |- 11:0:11:6  sddn 71:80   active ready running
  |- 11:0:15:6  sdfb 129:208 active ready running
  |- 12:0:1:6   sdgp 132:80  active ready running
Note 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.

Non-ASA configurations

For non-ASA configurations, there should be two groups of paths with different priorities. The paths with higher priorities are Active/Optimized, meaning they are serviced by the controller where the aggregate is located. The paths with lower priorities are active but are non-optimized because they are served from a different controller. The non-optimized paths are only used when optimized paths are not available.

Example

The following example displays the correct output for an ONTAP LUN with two Active/Optimized paths and two Active/Non-Optimized paths:

# multipath -ll
3600a0980383036347ffb4d59646c4436 dm-28 NETAPP,LUN C-Mode
size=10G features='3 queue_if_no_path pg_init_retries 50' hwhandler='1 alua' wp=rw
|-+- policy='service-time 0' prio=50 status=active
| |- 16:0:6:35 sdwb  69:624  active ready running
| |- 16:0:5:35 sdun  66:752  active ready running
`-+- policy='service-time 0' prio=10 status=enabled
  |- 15:0:0:35 sdaj  66:48   active ready running
  |- 15:0:1:35 sdbx  68:176  active ready running
Note A single LUN shouldn't require more than four paths. More than eight paths might cause path issues during storage failures.

The OL 8.8 OS is compiled to recognize ONTAP LUNs and automatically set all configuration parameters correctly for both ASA and non-ASA configurations. You can further optimize performance for your host configuration with the following recommended settings.

The multipath.conf file must exist for the multipath daemon to start. If this file does not exist, you can create an empty, zero-byte file by using the following command:

touch /etc/multipath.conf

The first time you create the multipath.conf file, you might need to enable and start the multipath services by using the following commands:

# chkconfig multipathd on
# /etc/init.d/multipathd start

There is no requirement to add anything directly to the multipath.conf file unless you have devices that you don't want multipath to manage or you have existing settings that override defaults. To exclude unwanted devices, add the following syntax to the multipath.conf file, replacing <DevId> with the WWID string of the device you want to exclude:

blacklist {
        wwid <DevId>
        devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*"
        devnode "^hd[a-z]"
        devnode "^cciss.*"
}
Example

The following example determines the WWID of a device and adds it to the multipath.conf file.

Steps

  1. Determine the WWID:

    # /lib/udev/scsi_id -gud /dev/sda
360030057024d0730239134810c0cb833

    sda is the local SCSI disk that you want to add to the blacklist.

  2. Add the WWID to 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.*"
}

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 must be corrected by later stanzas in the multipath.conf file that apply specifically to ONTAP LUNs. Without this correction, the ONTAP LUNs might not work as expected. You should only override these defaults in consultation with NetApp, the OS vendor, or both, 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

2 pg_init_retries 50

flush_on_last_del

yes

hardware_handler

0

no_path_retry

queue

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
Example

The following example demonstrates how to correct an overridden default. In this case, the multipath.conf file defines values for path_checker and no_path_retry that are not compatible with ONTAP LUNs. If they cannot be removed because other SAN arrays are still attached to the host, these parameters can be corrected specifically for ONTAP LUNs with a device stanza.

defaults {
 path_checker readsector0
 no_path_retry fail
 }
devices {
 device {
 vendor "NETAPP "
 product "LUN.*"
 no_path_retry queue
 path_checker tur
 }
}
Note To configure Oracle Linux 8.8 Red Hat Enterprise Kernel, use the recommended settings for Red Hat Enterprise Linux (RHEL) 8.8.

KVM settings

You can also use the recommended settings to configure a Kernel-based Virtual Machine (KVM). There are no changes required to configure a KVM as the LUN is mapped to the hypervisor.

Known issues

There are no known issues for the Oracle Linux 8.8 with ONTAP release.