When you connect an SAP HANA host to a Unity XT storage array using the FC protocol, you must connect two host bus adapter (HBA) ports supporting 16 Gb/s link speed to the Unity XT array. We recommend using two redundant HBAs for high availability, but you can use a single dual-port HBA as well.

Connect and zone each port over the FC SAN network to two FC FE ports per storage processor on the Unity XT array. This setup produces two active and two standby paths per LUN, as shown in the following figure:

Figure 5.                  Redundant Fibre Channel host connection

After the HBAs have been zoned to the Unity XT FC front-end ports, use the Unisphere UI to create a host entry in the Unity XT system and add LUNs to the host. Follow these steps:

1. From the Unisphere dashboard, select Access > Hosts, click the + icon, and then click Host.

The following page is displayed:

Figure 6.              Adding a host using Unisphere

2. Click Next.

The following page is displayed:

Figure 7.              Unisphere host properties: FC initiators

3. Select the two FC initiators (WWNs) of the SAP HANA host HBAs from the list of automatically discovered initiators, and then click Finish.

You can now create LUNs and add them to the host.

4. From the host list in Unisphere, double-click the host to edit the entry.

To add LUNs, click the LUNs tab and the + icon. You can choose between creating LUNs or adding existing LUNs.

To create LUNs, follow the guidelines in Create LUNs for Fibre Channel. For a host entry for an SAP HANA single host (scale-up), the SAP HANA persistence requires both a data LUN and a log LUN. For a host entry for an SAP HANA host that is part of an SAP HANA scale-out cluster, the host requires access to all SAP HANA persistence LUNs in the cluster.

Scan LUNs on the host and create file systems

To scan the new LUNs on the SAP HANA host, run the following command:

rescan-scsi-bus.sh

After the new LUNs have been rescanned and are visible to the host, add them to multipathing (DM-MPIO). Native Linux multipathing (DM-MPIO) must be enabled on the Linux host. When multipathing is enabled, the host accesses the block LUNs over multiple paths, which provides redundancy in case of a component failure.

Multipathing is controlled by the /etc/multipath.conf file. The file does not exist by default. Create the file by running the following command:

multipath -t > /etc/multipath.conf

The Unity XT devices are controlled under the ^DGC device section. All default settings work for FC devices; however, it might be necessary to change some of the settings based on specific requirements, for example to exclude some block devices, such as the internal server devices from multipathing.

After the block devices are under multipath control, display them by running the following command:

multipath -ll

The following sample output shows two devices:

When the block devices are under multipath control, you can format them by using XFS and mount them as required.

To format the block device, run the following (sample) command:

mkfs.xfs /dev/mapper/3600601604f804a00fc8a775d7498625e

When installing an SAP HANA single-node instance, automate the mounting of the SAP HANA persistent devices by running /etc/fstab. For example:

/dev/mapper/3600601604f804a00079d565d880a5877 /hana/data xfs rw,relatime,noquota 0 0

/dev/mapper/3600601604f804a00fc8a775d7498625e /hana/log xfs rw,relatime,noquota 0 0

When you install an SAP HANA multimode scale-out cluster, the SAP HANA storage connector (fcClient) mounts the devices during SAP HANA startup.